bacillus cereus, a volatile human pathogenbacillus cereus is a gram-positive,...

CLINICAL MICROBIOLOGY REVIEWS, Apr. 2010, p. 382–398 Vol. 23, No. 20893-8512/10/$12.00 doi:10.1128/CMR.00073-09Copyright © 2010, American Society for Microbiology. All Rights Reserved.

Bacillus cereus, a Volatile Human PathogenEdward J. Bottone*

Division of Infectious Diseases, Mount Sinai School of Medicine, New York, New York, and Division ofInfectious Diseases, New York Medical College, Valhalla, New York

INTRODUCTION .......................................................................................................................................................382EPIDEMIOLOGY.......................................................................................................................................................383MICROBIOLOGY ......................................................................................................................................................383

Bacterial Morphology.............................................................................................................................................383Colony Morphology.................................................................................................................................................384

PATHOGENESIS........................................................................................................................................................384NONGASTROINTESTINAL INFECTIONS ...........................................................................................................385

Respiratory Tract Infections .................................................................................................................................385Nosocomial Infections ............................................................................................................................................385

ENDOPHTHALMITIS ...............................................................................................................................................386Case Vignette ...........................................................................................................................................................386Endophthalmitis Pathogenesis..............................................................................................................................388Blood-Ocular Barrier .............................................................................................................................................389

CENTRAL NERVOUS SYSTEM INFECTIONS....................................................................................................389Case Vignette ...........................................................................................................................................................389

GAS GANGRENE-LIKE INFECTIONS..................................................................................................................390DIFFERENTIATION OF B. CEREUS FROM C. PERFRINGENS ......................................................................391

Case Vignette ...........................................................................................................................................................391CUTANEOUS INFECTIONS DUE TO TRAUMA.................................................................................................391PRIMARY CUTANEOUS INFECTIONS ................................................................................................................392ENDOCARDITIS ........................................................................................................................................................393OSTEOMYELITIS......................................................................................................................................................393URINARY TRACT INFECTIONS............................................................................................................................393ANTIBIOTIC SUSCEPTIBILITY.............................................................................................................................394CONCLUSIONS .........................................................................................................................................................394ACKNOWLEDGMENTS ...........................................................................................................................................395REFERENCES ............................................................................................................................................................395

INTRODUCTION

In 1993, Drobniewski (40) published a major review in thisjournal, entitled Bacillus cereus and Other Related Species,which followed “Farrar’s landmark review” published 30 yearsearlier (45). Continuing on the “shoulders of these giants” andreviewing and dissecting the expanding horizon of publicationson B. cereus non-gastrointestinal-tract infection, one becomestruly fascinated by the diligence of the author’s depiction of theevolving spectrum of human infections associated with thisbacterium, which has heretofore been regarded as a “contam-inant” when isolated from a clinical specimen. Furthermore,immersion into the details of the infectious process and un-covering potential routes of pathogenesis even when not spe-cifically elucidated by the authors afforded a wonderful oppor-tunity to integrate concepts derived in part from the numerouspublications reviewed in a Sherlock Holmes manner to arriveat a rationale for the infectious process described. In thoseinstances scenarios were interjected based upon new-foundknowledge and personal experiences where relevant. In the

end, it is hoped that the reader would become enlightened andintrigued with the kaleidoscopic nature of this volatile bacterialspecies.

The joy in the undertaking of this topic resides in reviewingand appreciating the insights of early investigators who recog-nized the pathogenic potential of “Bacillus species” other thanB. anthracis. Their determined endeavors sought to alert themedical community to the biphasic contaminant-pathogen dif-ferentiation of B. cereus. Such a distinction is critical in orderto embark on the correct therapeutic approach prior to havingto backtrack because of misconceptions regarding the signifi-cance of a B. cereus isolate from a patient specimen. To thisend, this review, which focuses mainly on non-food-borne in-fections, will reemphasize the plea of past authors who soughtto give B. cereus a well-earned pathogenic status worthy ofserious clinical evaluation when encountered. The reader isreferred to a comprehensive review of B. cereus food poisoningby Arnesen et al. (7).

Bacillus cereus is a Gram-positive, aerobic-to-facultative,spore-forming rod widely distributed environmentally andbearing a close phenotypic and genetic (16S rRNA) rela-tionships to several other Bacillus species, especially B. an-thracis (8).

The bacterium exists as a spore former and vegetative cell innature and as a vegetative cell when colonizing the human

* Mailing address: Division of Infectious Diseases, Box 1090, MountSinai School of Medicine, One Gustave L. Levy Place, New York, NY10029. Phone: (212) 241-6741. Fax: (212) 534-3249. E-mail: [email protected].

382

on May 23, 2020 by guest

http://cmr.asm

.org/D

ownloaded from

https://crossmark.crossref.org/dialog/?doi=10.1128/CMR.00073-09&domain=pdf&date_stamp=2010-04-01

http://cmr.asm.org/

body (see Epidemiology below). Transmission electron micros-copy of the vegetative cell reveals a cytoplasmic membranesurrounding the cellular content (79, 80). In addition, somestrains contain an outermost crystalline surface protein (Slayer) (79, 80). The core of the spore is surrounded by theinner membrane, cortex, and inner and outer coats. Whiledevoid of metabolic activity, the B. cereus spore is refractory toextreme environmental conditions inclusive of heat, freezing,drying, and radiation and may be regarded as the infectiveagent for this bacterium.

In keeping with its close relationship to B. anthracis, thesurface antigens of the spore share epitopes with B. anthracisspores as determined serologically by cross-agglutination (17).In the food industry the spores of B. cereus are particularlytroublesome because spores can be refractory to pasteurizationand gamma radiation, and their hydrophobic nature allowsthem to adhere to surfaces (5, 79, 111).

EPIDEMIOLOGY

The natural environmental reservoir for B. cereus consists ofdecaying organic matter, fresh and marine waters, vegetablesand fomites, and the intestinal tract of invertebrates (71), fromwhich soil and food products may become contaminated, lead-ing to the transient colonization of the human intestine (53).Spores germinate when they come into contact with organicmatter or within an insect or animal host (7). A multicellularfilamentous growth pattern containing refractile inclusions,termed arthromitus (rooted), has been observed in the guts ofcertain arthropods, which is regarded as the normal intestinalstage in soil-dwelling insects (95). In this setting, as long rod-shaped bacteria, the bacilli lose their flagella, attach to thearthropod intestinal epithelium, and sporulate (95). B. cereusalso has a saprophytic life cycle in which spores germinate insoil, with the production of a vegetative bacillus, which couldthen sporulate, maintaining the life cycle (7). Defecation by ordeath of the host releases cells and spores into the soil, wherevegetative cells may sporulate and survive until their uptake byanother host (71, 135). Furthermore, when B. cereus grows insoil, it undergoes a switching from a single-cell to a multicel-lular phenotype, which allows it to translocate through the soil

(135). This morphogenic phase is analogous to B. cereusswarming on agar media (118).

B. cereus may be the most common aerobic spore bearer inmany types of soil and in sediments, dust, and plants (107). B.cereus is also frequently present in food production environ-ments due to the adhesive nature of its endospores (7). Thischaracteristic enables the bacterium to spread to all kinds offood.

Because of the ubiquitous distribution of B. cereus in foodproducts, the bacterium is ingested in small numbers and be-comes part of the transitory human intestinal flora (71, 130). Itis unclear, however, if the recovery of B. cereus in cultures ofstool specimens is a function of germinating spores or thegrowth of vegetative cells.

MICROBIOLOGY

Bacterial Morphology

Microbiologically, members of the B. cereus group exclu-sive of B. anthracis display a range of morphological formsdepending upon the milieu in which they are observed. InGram-stained smears of body fluids such as anterior-cham-ber aspirates or broth cultures, B. cereus presents as straightor slightly curved slender bacilli with square ends singly or inshort chains (Fig. 1). Clear-cut junctions separating mem-bers of the chain are distinctly displayed. Gram-stainedsmears prepared from agar growth will show more uniformbacillary morphology with oval, centrally situated spores,which do not distort the bacillary form. In tissue sectionssuch as those shown in Fig. 2, long, slender, bacillary formsmay predominate, with some clearly displaying polyhydroxy-butyrate vacuoles, which may be confused with spores. Longfilamentous forms characterized as filamentation may alsoshow beading, which may preclude identification as a Bacil-lus species (Fig. 3). In wet preparations of body fluids orbroth cultures, the peritrichous bacilli are motile, displayinga leisurely gait rather than darting motility.

FIG. 1. Gram stain of blood culture showing Gram-positive slenderbacilli with rounded ends singly, in pairs, and in short chains.

FIG. 2. Gram stain of hemorrhagic brain biopsy specimen withhistological sections showing clusters of elongated bacillary forms.

VOL. 23, 2010 BACILLUS CEREUS, A VOLATILE HUMAN PATHOGEN 383


http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

Colony Morphology

When grown under aerobic conditions on 5% sheep bloodagar at 37°C, B. cereus colonies are dull gray and opaque witha rough matted surface (Fig. 4). Colony perimeters are irreg-ular and represent the configuration of swarming from the siteof initial inoculation, perhaps due to B. cereus swarming mo-tility (118). Zones of beta-hemolysis surround and conform tothe colony morphology (131). In some instances smooth colo-nies develop either alone or in the midst of rough colonies(Fig. 4). When grown apart from the initial inoculum, smoothcolonies are surrounded by a uniform zone of beta-hemolysisframing the centrally situated colony (Fig. 5). Interestingly,smears prepared from the distal and frontal (spreading) ad-vancing perimeters of a mature colony may reveal two distinctmorphological presentations. Smears prepared from the distaledge show uniform bacillary forms with prominent centrallysituated spores admixed with chains of Gram-positive bacilli,while smears from the advancing edge are comprised predom-inately of masses of entangled bacillary chains traversing the

microscopic field and a remarkable absence of spore-contain-ing bacilli. Perhaps, as the colony spreads forward from theinitial inoculum site, it leaves behind a trail of metabolic endproducts, which alters the pH and oxygen content of thegrowth environment, thereby inducing spore formation. B.cereus grows anaerobically and at 45°C. Biochemical charac-terization can be achieved through the use of the API 20Enterobacteriaceae (API 20 E) and API 50 Carbohydrate (50CH) kits (bioMerieux, France), used together (88).

PATHOGENESIS

The pathogenicity of B. cereus, whether intestinal or nonin-testinal, is intimately associated with tissue-destructive/reactiveexoenzyme production. Among these secreted toxins are fourhemolysins (56), three distinct phospholipases, an emesis-in-ducing toxin, and three pore-forming enterotoxins: hemolysinBL (HBL), nonhemolytic enterotoxin (NHE), and cytotoxin K(91, 92, 114). In the gastrointestinal tract (small intestine),vegetative cells, ingested as viable cells or spores, produce andsecrete a protein enterotoxin and induce a diarrheal syndrome,whereas emetic toxin, a plasmid-encoded cyclic peptide (cereu-lide), is produced in food products and ingested preformed. Inrabbit ligated ileal-loop assays, culture filtrates of enterotoxi-genic strains induce fluid accumulation and hemolytic, cyto-toxic, dermonecrotic, and vascular permeability activities inrabbit skin (13).

This tripartite enterotoxin is composed of a binding compo-nent (B) and two hemolytic components, designated HBL (13).Also diarrheagenic in the gastrointestinal tract is a nonhemo-lytic three-component enterotoxin, designated NHE (91). Theemetic toxin, which induces a vomiting syndrome, is synthe-sized in the contaminated food product, e.g., milk, rice, andpasta, in which B. cereus is growing and may represent a met-abolic product of growth.

FIG. 3. Filamentation phenomenon consisting of intertwined beadedbacilli as shown in Gram stains of agar cultures.

FIG. 4. Gray, opaque, granular, spreading colonies with irregularperimeters growing on 5% sheep blood agar. Note the smaller smoothcolonies admixed among spreading growth.

FIG. 5. Smooth colonies on 5% sheep blood agar surrounded by auniform zone of beta-hemolysis.

384 BOTTONE CLIN. MICROBIOL. REV.


http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

NONGASTROINTESTINAL INFECTIONS

In addition to food poisoning, B. cereus causes a number ofsystemic and local infections in both immunologically compro-mised and immunocompetent individuals. Among those mostcommonly infected are neonates, intravenous drug abusers,patients sustaining traumatic or surgical wounds, and thosewith indwelling catheters. The spectrum of infections includefulminant bacteremia, central nervous system (CNS) involve-ment (meningitis and brain abscesses), endophthalmitis, pneu-monia, and gas gangrene-like cutaneous infections, to namea few.

Respiratory Tract Infections

Bacillus anthracis possesses two plasmids, pX01 and pX02,which encode the lethal toxin and the poly-D-glutamic acidcapsule, respectively, which would normally distinguish thisbacterium from the closely related B. cereus. Although thesetwo species differ in phenotypes and disease spectra produced,reports of pulmonary infections mimicking anthrax have beenattributed to B. cereus strains harboring B. anthracis toxingenes (67).

In 1997, Miller et al. (99) described rapidly progressivepneumonia and bacteremia in two previously healthy weldersaged 46 and 41 years, respectively, without any enjoining epi-demiological link. Patient 1 was a resident of central Louisianawho was healthy 5 days prior to hospital admission, whilepatient 2 lived in South Louisiana and was healthy until 3 daysprior to hospitalization. According to these authors, the over-whelming sepsis and pulmonary infiltrates in the two patientsresembled those produced by Bacillus anthracis respiratory dis-ease. It was postulated that welders acquired their infection bythe inhalation of B. cereus spores from contaminated dust.While these two case presentations paralleled pulmonary in-fection by B. anthracis, the two isolates were not initially testedfor the presence of B. anthracis toxin genes. However, a laterpublication by Hoffmaster et al. (67) stated that the Millerisolates did not contain the B. anthracis pagA-like genes carriedon the pXO1 phage. Seven years later, Hoffmaster and col-leagues (68), working with B. cereus strain G9241, isolatedfrom the sputum and blood of a nonimmunosuppressed pa-tient with an illness resembling pulmonary anthrax, showedthat the B. cereus isolate harbored a plasmid homologue of theB. anthracis pXO1-carried PA toxin gene pagA but not thepXO2 glutamic acid capsule gene. The patient was well until 2days before the onset of symptoms and, analogous to the twopatients reported by Miller et al. (99), did not abuse drugs oralcohol and was a nonsmoker without underlying disease. Hereceived intensive care, including a partial lobectomy, and wasdischarged 44 days postadmission.

More recently, in 2007, Avashia et al. (10) reported twometal workers with fatal B. cereus pneumonia and sepsis. Nei-ther patient, aged 39 and 56 years, respectively, had any sig-nificant predisposing comorbidities, both worked as metalworkers grinding metal for polishing, and, while both wereresidents of Texas, they were substantially separated geograph-ically. Both patient isolates tested positive for the pXO1-spe-cific virulence plasmid but not the pXO2 plasmid by PCR.

Interestingly, while the B. cereus isolates reported by Miller

et al. (99) were lacking B. anthracis genes (67), the clinicalpresentation and occupation of the two patients who suc-cumbed to the infection remarkably resembled the clinicalpresentation and occupation of patients subsequently reportedby Avashia et al. (10) and Hoffmaster et al. (68). Perhaps, theMiller isolate lost the B. anthracis genes during the 7-yearinterval between initial isolation and testing by Hoffmaster etal. (68). Alternatively, plasmids carrying B. anthracis genes maynot be required for severe pulmonary infections, as other iso-lates from severe cases have been negative for plasmids (A.Hoffmaster, personal communication).

Regarding the upper respiratory tract, invasion of the oralcavity in immunosuppressed patients may be more prevalentthan previously documented, as the oral cavity may becomecolonized with B. cereus either through the inhalation ofspores or by vegetative bacteria passing through in B. cereus-contaminated food (31, 44). Foci can be established by theentrapment of bacteria in furrows in the oral cavity in whichthe bacterium may develop locally and elaborate toxins,which can spread to adjacent tissues, or the bacterium candisseminate to other body sites. A report by Strauss et al.(124) of the development of pseudomembranous tracheo-bronchitis in a 52-year-old female patient with aplastic ane-mia suggests that treatment-mediated damage to the buccalmucosa may expedite spore/vegetative cell adherence andcolonization. Fiber-optic bronchoscopy of the patient re-vealed a severely inflamed tracheal and bronchial mucosaaccompanied by white diphtheria-like membranes obstruct-ing the lower lobe bronchi on the left side. Over an 8-hperiod, the membranes spread and obstructed the entirevisible bronchial system. B. cereus was recovered from bloodand bronchoalveolar lavage cultures and the membranebiopsy specimen. As this patient’s initial symptoms includedchest pain, yellowish sputum, and a rapid progression of theinfection, the authors likened her infection to pulmonaryanthrax. B. cereus colonization of the oral cavity, as notedhere and elsewhere (31, 44), may well be an underappreci-ated first stage in the pathogenesis of pulmonary as well assystemic infections in immunocompromised individuals.

Bacillus cereus spores, which are hydrophobic and have pro-jecting appendages, adhere to Caco-2 and small-intestine epi-thelial cells (5) and HeLa cells (110). In these studies, sporesadhered in aggregates, which, when germinating, released highconcentrations of tissue-destructive toxins. Contact adherenceof spores in aggregates to epithelial cells triggers the germina-tion of spores, enterotoxin production, and disintegration ofthe Caco-2 tissue monolayer. Interestingly, bacteria continueto adhere to membrane debris (110). While these studies em-phasized the adherence of B. cereus spores mainly to colonicepithelia, the ingestion of spores with binding capability in thesetting of potentially disrupted respiratory mucosa could leadto cytotoxicity in the respiratory tract, as exemplified by thedevelopment of diphtheria-like membranes in addition to pul-monary infection and systemic dissemination.

Nosocomial Infections

Due to the widespread distribution of Bacillus spores in soil,dust, water, and the hospital environment, B. cereus is usuallyconsidered a contaminant when isolated from clinical speci-



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

mens of various origins (blood, wounds, and sputum, etc.).Bacillus species, however, are gaining notoriety as causing de-finitive nosocomial outbreaks among immunosuppressed hos-pitalized patients (106, 108; reviewed in Table 1). Environmen-tal reservoirs identified for this species include contaminatedair filtration and ventilation equipment (23), fiber-optic bron-choscopy equipment (55, 109), linen (12), gloves (139), handsof staff (101), intravenous catheters (64), alcohol-based handwash solutions (69), specimen collection tubes, balloons usedin manual ventilation (134), linens (10, 11), and reused towelsin Japan (38). Furthermore, a 17-year-old neutropenic patientwith acute lymphoblastic leukemia developed B. cereus bacte-remia traced to drinking lukewarm tea prior to her bacteremicepisode (44). A thorough investigation by those authorsshowed a high prevalence (17 of 19 tea bags) of contaminationby B. cereus.

As noted previously, outbreaks of B. cereus pseudoinfectionsamong hospitalized patients have been well documented, es-pecially with regard to pseudobacteremias (16, 69, 139). Apseudo-outbreak has been defined as a situation in which anorganism is recovered in culture at a rate that is greater thanexpected and that cannot be correlated clinically with the sup-posed infection implied by the culture results (94). There is noquestion that spores of B. cereus (as with other Bacillus species)permeate hospital environments and contribute to nosocomialand pseudonosocomial infections. Pseudo-outbreaks of bacte-remia and respiratory tract infections have been traced tocontaminated ethyl alcohol (69) and fiber-optic bronchoscopyequipment (55, 109), respectively.

Because most Bacillus species (except B. anthracis) isolatedfrom blood cultures and even from open wounds are oftenregarded as contaminants, it becomes critical for the clinicalmicrobiology laboratory to alert infection control practitionersif a sudden increase in the isolation of this bacterial species isnoted. If such a scenario arises, B. cereus isolates should be

forwarded to a reference center for serotyping and/or sub-jected to genotypic fingerprinting (86) to determine if isolatesare clonal, which could lead to a point source of contamina-tion.

Catheter-related B. cereus bloodstream infections have beenwell documented, especially among immunosuppressed pa-tients and those with hematological malignancies (82, 106). Itwas previously shown that B. cereus can produce biofilms (9,82), which can play a major role in attachment to catheters.When examined by scanning electron microscopy after growthon inoculated coverslips, B. cereus isolates associated with nos-ocomial bacteremia formed aggregates of bacilli, which couldeasily attach to the surface of catheters, resulting in persistentinfection until catheter removal. Biofilm formation can resultfrom cell-to-cell and cell-surface contact, which leads to theformation of microcolonies. The release of planktonic bacteriafrom the biofilm can result in the formation of additionalbiofilms, thereby maintaining persistence (33). While antibiotictherapy may arrest planktonic invasion, sessile bacteria in thebiofilm are spared, resulting in recurrent or protracted bacte-remia. Biofilm formation, because of their protected mode ofgrowth on inert surfaces, may also contribute to B. cereuspersistence in the hospital environment in settings whereinreplication can take place, in addition to the survival of spores.

ENDOPHTHALMITIS

Case Vignette

A 45-year-old patient with a history of insulin-dependentdiabetes mellitus presented with redness and worsening painin his left eye 3 days post-cataract surgery. A rapid diagnosisof endophthalmitis was made by Gram staining of vitreousfluid, which showed numerous Gram-positive bacilli (Fig. 6).Wet preparation of the vitreous fluid showed motile bacilli.

TABLE 1. Reported nosocomial Bacillus cereus infections, 1993 to 2009a

Yr Reference(s) No. of patients Infection risk factor(s) Source(s) of infection Outcome

1993 23 16 ventilated patients inmedical/surgical ICU

Ventilation/ICU,bacteremia, pneumonia

Ventilation equipment 1 died

1994 10, 11 2 Meningitis postneurosurgery Contaminated hospital linenin OR

Expired

2000 134 3 neonates Bacteremia, meningitis,preterm (neonatesimmunosuppressed)

Balloons used in manualventilation, hands ofnursing staff

1 died

2000–2005 38 16, 5 studied in detail Bacteremia, cecal cancer,esophageal cancer,chronic kidney failure,cholangitis, ALL

Catheters, reused dried andsteamed towels, washingmachines in hospital linenrooms

5 case vignettes presented;antibiotics administered,outcomes not given

2003 64 1 Bacteremia cholecystectomy Nutrition via central catheter Survived2004 44 1 (ALL) Bacteremia (ALL) Contaminated tea bags Not given, survived(?)2006 106 3 (AML) Bacteremia (AML),

pneumonia (AML),bacteremia (AML),pneumonia (AML),septicemia (AML)

Nonsterile cotton wool usedfor skin disinfection

Died (ventilation-associated pneumonia)

2009 82 18 Bacteremia, malignancy,COPD, CVA

Gauze, catheter tip, hospitalenvironment, steamed towel,and alcoholic cotton pot

Not given

a ICU, intensive care unit; ALL, acute lymphocytic leukemia; AML, acute myelogenous leukemia; CVA, cardiovascular accident; COPD, chronic obstructivepulmonary disease.



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

Despite the administration of intravitreal and systemic van-comycin and ceftazidime on the day of admission, the infec-tion progressed, requiring the enucleation of the eye on thesame day. Cultures of vitreous fluid and blood grew B.cereus.

Endophthalmitis is a vision-threatening eye infection result-ing from traumatic or systemic microbial infection of the inte-rior of the eye (24). The outcome of the infection varies withthe microbial agent involved and the rapidity of and responseto treatment. The hallmark of the ophthalmic lesion is a cor-neal ring abscess accompanied by rapid progression of pain,chemosis, proptosis, retinal hemorrhage, and perivasculitis.Systemic manifestations include fever, leukocytosis, and gen-eral malaise (97).

With regard to B. cereus, as exemplified in the case describedabove, endophthalmitis caused by this bacterium is a devastat-ing malignant eye infection because of the rapidity with whichthe infection progresses and the bacterium’s elaboration of amultitude of extracellular tissue-destructive virulence factors(14). In his exceptional review of B. cereus infections, Drob-niewski (40) detailed the results of 35 cases of B. cereus en-dophthalmitis “reported during this century,” of which 20 eyeswere lost to enucleation and 1 was lost to blindness. In theirreview of B. cereus endophthalmitis, Callegan et al. (28) noteda 70% loss of total vision resulting from enucleation or evis-ceration. It is noteworthy that during the first half of the 20thcentury, bacilli isolated from cases of endophthalmitis were notidentified to the species level and subsequently were allgrouped as Bacillus subtilis (36). In 1952, Davenport and Smith(36) described a patient with B. cereus endophthalmitis basedon identification criteria of their isolate published 4 years ear-lier in Bergey’s Manual of Determinative Bacteriology (68a). Astheir patient’s clinical presentation closely mimicked those ofearlier reports of endophthalmitis attributed to B. subtilis, Dav-enport and Smith raised the thought that those earlier reportsof endophthalmitis attributed to B. subtilis were actually “anerror of taxonomy.”

B. cereus endophthalmitis can be divided into two categories:exogenous, attributable to globe-penetrating eye trauma, andendogenous, originating through the hematogenous seeding of

the posterior segment of the eye from a distant site or throughdirect intravenous acquisition through blood transfusion (75),indwelling devices, or contaminated needles or injection par-aphernalia or illicit drugs (59, 98, 119, 127) or by iatrogenicadministration of medications such as B vitamins (21) andinsulin (101). Bouza et al. (21) reported a case of severe sup-purative endogenous panophthalmitis caused by B. cereus in a43-year-old man, which resulted from the intravenous admin-istration of B vitamins obtained from three multidose vitamin-and mineral-containing vials, which, when cultured, grew purecultures of B. cereus. The patient received twice-weekly intra-venous injections by his private physician for several weeks.The last injection was administered less than 24 h prior to theonset of the patient’s ocular symptoms, which consisted of a12-h history of pain, swelling, and severe loss of vision in theright eye.

In 1953, Kerkenezov (75) described a patient who had de-veloped B. cereus endogenous panophthalmitis following ablood transfusion, although the blood was not cultured. In thisinstance, it is conceivable that other items, e.g., alcoholsponges and gloves, etc., could have been contaminated withB. cereus spores, which ultimately led to bacteremia and en-dophthalmitis.

Hematogenous invasion of the eye among intravenous drugabusers, attributable to contaminated heroin (138), cocaine(98), and injection equipment (128) has been documented.Shamsuddin et al. (119) cultured 59 samples of heroin andinjection paraphernalia, of which 20 cultures were positive.Bacillus species were recovered from 13 of the 20 samples, 5(38%) of which were B. cereus. In their earlier study (127),these investigators recovered Bacillus species from 47 of 89paraphernalia cultures and 32 of 68 heroin cultures. B. cereuswas the species most commonly isolated. Furthermore, B.cereus keratitis or more significant eye infections in contactlens wearers has been associated with acquiring the microor-ganism from contaminated contact lens care systems (39).Donzis et al. (39) pointed out that Bacillus spores can survivemultiple heat disinfection treatments as well as chemical dis-infection systems used for the minimum recommended lenscare techniques.

Suspicion of the presence of B. cereus in a penetrating eyeinfection may be related to occupation, e.g., metal workers (97),and if the injury occurred in a rural area or agricultural setting(37) or following cataract extraction surgery (case history). Re-garding the latter, Simini (120) reported an outbreak of B. cereusnecrotizing endophthalmitis secondary to surgery for senile cata-ract. Within a day of surgery, all four patients lost vision in theaffected eye. Although a single ophthalmologist was a member onall of the surgical teams operating on the four patients in the sameoperating room (OR) on the same day, no source of infectioncould be identified, as a bacteriological investigation was notundertaken until 3 days postsurgery. Based upon previous reportsof B. cereus nosocomial infections, as outlined in Table 1, con-taminated fomites such as gauze, linens, and ventilators, etc., inaddition to health care workers’ hands, may have served as thesource of the B. cereus outbreak.

Diagnosis of endogenous and exogenous B. cereus endoph-thalmitis should be attempted by immediate anterior-chamberparacentesis. If microorganisms are not detected, this should

FIG. 6. Numerous Gram-positive bacilli in a smear of an anterior-chamber aspiration sample from a patient with post-cataract surgeryendophthalmitis.



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

be followed by a second vitreous aspiration after a short inter-val (98), along with blood culture collection (57).

Because of the rapidity with which B. cereus can destroy aninfected eye, especially in cases of penetrating trauma with asoil-contaminated foreign body, rapid therapeutic interventionis mandatory irrespective of results of immediate diagnostictesting (37). Early studies suggested the efficacy of intravitrealantibiotics, namely, 1,000 �g of vancomycin in combinationwith 400 �g of amikacin (133). Factors contributing to theoutcome of B. cereus endophthalmitis include duration be-tween injury and treatment therapy chosen and condition ofthe eye upon presentation (26, 49). Systemic antibiotics havebeen used in concert with intravitreal antibiotics, but it isnoteworthy that vancomycin and aminoglycosides do notreadily penetrate into the vitreous fluid (46) due to the pro-tective effect of the blood-ocular fluid barrier (26).

Using B. cereus to induce endophthalmitis in a rabbitmodel, Liu and Kwok (87) injected 20 rabbit eyes intravit-really with 0.1 ml of an isotonic sodium chloride solutioncontaining 1 � 106 CFU of B. cereus. After 24 h, 1 mg ofvancomycin alone in 0.1 ml of saline was administered in-travitreally, and in a second group of rabbit eyes infectedwith B. cereus, 1 mg of vancomycin and 0.4 mg of dexameth-asone were simultaneously administered intravitreally. Eyestreated with vancomycin and dexamethasone examined at 7and 14 days expressed significantly less inflammation overthe conjunctiva and vitreous fluid at 7 days and over the irisand vitreous fluid than did eyes treated with vancomycintreatment alone. In reviewing reports of naturally acquiredB. cereus as well as experimentally induced endophthalmitis,ocular entrance of the bacterium results in a massive de-struction of the eye within 12 to 18 h (26), and in manyinstances, vision loss occurs regardless of the therapeuticand surgical intervention, largely because of the delayedadministration of antibiotics, toxin production of the infect-ing strain, and migration and sequestration of the motilebacillus out of antibiotic reach (27). For instance, in exper-imental rabbit studies conducted by Callegan et al. (24), 100CFU of B. cereus was inoculated into rabbit eyes. Inflam-mation was observed at as early as 3 h, and from 12 to 18 h,inflammatory symptoms were severe, with anterior-chamberhyphema, severe iritis, and peripheral ring abscessespresent. The B. cereus strain used in their experiments wasrecovered from a pediatric posttraumatic endophthalmitiscase that progressed to enucleation. In contrast, no infor-mation was given regarding the source of the B. cereus strainused by Liu and Kwok (87) in their studies. This raises thepossibility that the strain used was of potentially reducedvirulence, since one would expect substantial damage to theeye during the 24-h interval from the inoculation and ad-ministration of vancomycin and dexamethasone. Perhaps,further studies with a clinically isolated, fully toxigenic B.cereus strain will confirm or temper the results obtained byLiu and Kwok (87).

Endophthalmitis Pathogenesis

It is well established that B. cereus elaborates a host oftissue-destructive exotoxins that contribute to the devastatingoutcomes in endophthalmitis (14). However, recent investiga-

tions into the pathogenesis of B. cereus-induced endophthalmi-tis have identified several other factors that also contribute tothe poor outcome of B. cereus endophthalmitis.

Initially, Beecher et al. (14) suggested that the poor out-come of antibiotic treatment of B. cereus endophthalmitiswas actually a consequence of continued tissue-destructiveactivity independent of antibiotic bacterial killing. Amongthe elaborated exotoxins incriminated in an experimentalrabbit model of destructive endophthalmitis conducted byBeecher et al. (14, 15) were hemolysin BL (a tripartitedermonecrotic vascular permeability factor), a crude exotoxin(CET) derived from cell-free B. cereus culture filtrates, phosphati-dylcholine-preferring phospholipase C (PC-PLC), and collage-nase. The contribution of these factors individually or in concertcould account for retinal toxicity, necrosis, and blindness inexperimentally infected rabbit eyes. The toxicity of PC-PLCwas a direct result of the propensity of the secreted enzyme forthe phospholipids in retinal tissue, which may also act similarlyin human eye retinal tissue, which also contains a significantamount of phospholipids (18). In a separate study, Callegan etal. (25) showed that the role of BL toxin in intraocular B. cereusinfection was minimal, “making a detectable contribution onlyvery early in experimental B. cereus endophthalmitis but didnot effect the overall course of infection.” Intraocular inflam-mation and retinal toxicity occurred irrespective of the pres-ence of hemolysin BL, implying the contribution of other fac-tors to pathogenesis.

In an experimental rabbit eye study of the pathogenesis ofbacterial endophthalmitis caused by the Gram-positive ocularpathogens Staphylococcus aureus, Enterococcus faecalis, andBacillus cereus, Callegan et al. (24) concluded that B. cereusendophthalmitis followed a more rapid and virulent coursethan the other two bacterial species. Additionally, B. cereusintraocular growth was significantly greater than those of S.aureus and E. faecalis. Analysis of bacterial location within theeye showed that the motile B. cereus rapidly migrates fromposterior to anterior segments during infection. This phenom-enon was confirmed in a subsequent study (27) using wild-typemotile and nonmotile B. cereus strains, which confirmed thatwhile both strains grew to a similar number in the vitreousfluid, the motile swarming strain migrated to the anterior seg-ment during infection, causing more severe anterior segmentdisease than the nonswarming strain.

Bacterial swarming is a specialized form of surface translo-cation undertaken by flagellated bacterial species. Swarm cellsin a population undergo a morphological differentiation fromshort bacillary forms to filamentous, multinucleate, and hyper-flagellated swarm cells with nucleoids evenly distributed alongthe lengths of the filaments (43, 52, 118). The differentiatedcells do not replicate but rapidly migrate away from the colonyin organized groups, which comprise the advancing rim ofgrowing colonies (43, 61, 118).

Swarming motility collectively stops, and swarm cells differ-entiate back into the short bacillary forms. Swarming isthought to be a mechanism by which flagellated microorgan-isms traverse environmental niches or colonize host mucosalsurfaces (4). Moreover, swarming can play a role in host-pathogen interactions by leading to an increase in the produc-tion of specific virulence factors (4, 52).

Regarding B. cereus, Ghelardi et al. (52) showed a correla-



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

tion between swarming and hemolysin BL secretion in a col-lection of 42 B. cereus isolates. The highest levels of toxin weredetected in swarmers, which suggested that swarming B. cereusstrains may have a higher virulence potential than nonswarm-ing strains.

Blood-Ocular Barrier

The eye is protected from inflammatory cells and bloodconstituents by the blood-ocular barrier systems (102). Thebarrier system separates the interior portion of the eye fromblood entering the eye and maintains the transparency andfunction of the interior portion of the eye. There are two mainblood-ocular barriers, the blood aqueous barrier and the bloodretinal barrier, a barrier to the free diffusion of moleculesformed by tight junctions (18, 30). During experimental B.cereus endophthalmitis, Moyer et al. (102) showed that thebacterium causes a permeability of the blood-retinal barrier asearly as 4 h postinfection by the disruption of tight junctionsbetween endothelial cells and the basement membrane of ret-inal capillaries and retinal pericytes. Such changes in theblood-ocular barrier during endophthalmitis contribute to theloss of retinal structure and function (78, 102). These authorsspeculated that a group of B. cereus toxins might have contrib-uted to the loss of barrier function in experimental B. cereusendophthalmitis.

CENTRAL NERVOUS SYSTEM INFECTIONS

Case Vignette

A 28-year-old male presented with a complaint of bruisingand bleeding of the gums and nose and a 2-week history ofwatery nonbloody diarrhea. Through the examination of abone marrow biopsy specimen, the patient was diagnosed withT-cell acute lymphocytic leukemia, for which induction chemo-therapy was administered. Seven days later, the patient devel-oped chills, which was followed by a febrile episode 2 dayslater. Blood cultures were obtained, which grew B. cereus bac-teria. That night, the patient expired. Autopsy revealed bilat-eral hemorrhagic necrosis of the brain (Fig. 7), with numerousGram-positive bacilli embedded in the necrotic areas (Fig. 2).

Central nervous system (CNS) invasion by B. cereus includes

meningitis (83, 129), meningoencephalitis (96), subarachnoidhemorrhage (3, 50, 74), and brain abscesses (70, 114, 125)occurring in pediatric (51, 102a) and adult (114) patients gen-erally in the setting of immunosuppression due to leukemiaand other malignancies. In reviewing these various reports,CNS infections occur secondarily to B. cereus bacteremia orfollowing induction chemotherapy (6, 51, 72, 74, 96). In a verydramatic presentation, two patients developed fulminant sepsisand massive intravascular hemolysis subsequent to inductionchemotherapy. Both patients had abdominal symptoms priorto bacteremia (6).

The pathogenesis of B. cereus CNS infection in most cases isobscure, although several risk factors are worthy of consider-ation. A substantial number of patients developed necrotizingbrain lesions following intrathecal induction chemotherapy(51, 72, 74, 96). Presumably, in addition to promoting neutro-penia, this procedure could introduce ubiquitous B. cereusspores from a multitude of environmental sources and fomites(see “Nosocomial Infections”). Other routes of acquisition in-clude bacteremia from a distal site and infected central venouscatheters (51) and other catheters used for the periodic ad-ministration of remission induction chemotherapy.

In a series of 12 patients described by Gaur et al. (51) fromwhom B. cereus was isolated from blood cultures, 4 had leuke-mia and underwent a lumbar puncture with the intrathecaladministration of chemotherapy in the week preceding CNSinfection. The introduction of B. cereus into the CNS duringthis procedure is conceivable. Further support for the intra-thecal route of acquisition of B. cereus is the absence of posi-tive blood cultures for some patients who developed CNSinfection following the intrathecal administration of chemo-therapy.

Several authors have advanced the possibility of the gastro-intestinal tract as a potential source of the B. cereus straininvolved in CNS infections, as patients either presented withgastrointestinal symptoms (nausea, vomiting, epigastric pain,or diarrhea) suggestive of food poisoning prior to CNS involve-ment (3, 50, 51, 101) or developed gastrointestinal symptomsconcomitant with CNS involvement (3, 96). The concept un-derscores the acquisition of B. cereus from an exogenoussource, e.g., food and water, etc., with gastric invasion, mucosalnecrosis, and spread to the liver and CNS via blood circulation(3, 50). Support for this premise can be acquired at autopsy,which may reveal liver involvement (abscesses and infarcts) (3,50, 51, 96, 140). Furthermore, Gaur et al. (51) reported therecovery of B. cereus from rectal swabs of three of four patientswith B. cereus bacteremia and meningitis within 72 h of hospi-tal presentation. Similarly, Funada et al. (50) isolated B. cereusin surveillance stool cultures of a leukemic patient who devel-oped fatal bacteremia with a clinical syndrome of acute gas-troenteritis, meningoencephalitis with subarachnoid hemor-rhage, and multiple liver abscesses and liver infarcts repletewith B. cereus infiltration. In an unrelated survey, Ghosh (53)isolated B. cereus from 14% of healthy adults in the generalpopulation and from a similar percentage of laboratory work-ers. Excretion rates persisted for 2 weeks. Ghosh concludedthat the colonization represented the intake of B. cereus in anindividual’s diet.

While the above-described speculations on B. cereus originsfrom the gastrointestinal tract are indeed intriguing, two sep-

FIG. 7. Hemorrhagic necrosis of brain due to B. cereus invasion ina patient with lymphocytic leukemia.



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

arate reports by Girsch and colleagues (54) and Le Scanff et al.(85) may well have advanced these concepts. Girsch et al. (54)described a premature, cesarean-section-delivered infant whodeveloped multiple small-bowel necrotic perforations and ab-dominal peritonitis 3 days postbirth. Culture of the abdominalcavity grew only B. cereus. These authors attributed the ne-crotic areas of the small intestine to B. cereus enterotoxins (91,129). One may draw a parallel between the infant’s gastroin-testinal pathology and that of leukemic patients whose immunesystem is markedly compromised by chemotherapy and whomay have acquired B. cereus intestinal colonization/infectiondue to chemotherapy-induced mucosal insult (85).

Le Scanff et al. (85) described a 37-year-old woman withacute myeloblastic anemia who developed sudden severe non-radiating epigastric pain accompanied by massive hematemesis2 months after induction chemotherapy. Upper gastrointesti-nal endoscopy showed a narrowed gastric lumen with severelyinflamed gastric mucosa with hemorrhagic, erosive, and ne-crotic areas extending from the corpus to the antral region.Gastric mucosa and blood culture grew only B. cereus. Histo-logical examination of biopsy specimens revealed extensivenecrosis and a large number of bacteria (bacilli) in the gastricmucosa. Those authors hypothesized that neutropenia, immu-nosuppressive treatment, and gastric mucosal injury due tochemotherapy may have facilitated B. cereus colonization ofthe gastric mucosa, leading to the onset of acute necrotizinggastritis. The source of B. cereus could have been food, swal-lowing respiratory secretions containing B. cereus colonizingthe throat (31), or hematological spread, although in this case,it was not clear if bacteremia preceded gastric invasion or wasa consequence of erosive gastric disease.

Two unusual cases of B. cereus meningitis were describedby overlapping authors at the University Hospital of Leiden,in which 19-year-old and, 4 years later, 18-year-old leukemiapatients developed B. cereus bacteremia and meningitis sub-sequent to chemotherapy-induced neutropenia. In the firstinstance (31), the 19-year-old patient who was being treatedfor active myelomonocytic leukemia under gnotobiotic con-ditions in a laminar-airflow isolation room was noted bythroat culture to be colonized with B. cereus a week prior tothe spread of the bacterium to the meninges, which resultedin the death of the patient within 48 h. Those authors statedthat B. cereus contamination of the isolated decontaminatedpatient was not surprising since food fed to the patient “isallowed to contain a small quantity of it” (B. cereus). Theauthors’ comment suggests that food for patients under gno-tobiotic isolation is treated to reduce bacterial concentra-tions and is cultured prior to feeding of the patient. In thisregard, the recovery of even a few colonies of B. cereus wasregarded as harmless until the bacterium was “cultured fromother than routine sites.”

The second case (60), involving the 18-year-old leukemicpatient, was indeed tragic, as the patient, on his last day oftreatment prior to being placed in protective isolation, wasallowed to take a short walk on the hospital grounds. By acci-dent, he fell, which resulted in a minor abrasion on his fore-arm, which was washed and cleansed and regarded as unim-portant. Over a 2-day period, the patient became febrile andcomplained of malaise, and his arm was not swollen but tender,with a demarcated erythematous area above the wound. Gram

staining of a serous exudate revealed “large Gram-positiverods thought to be Clostridium species because of his ‘streetinjury,’” and the patient was treated with penicillin. Concom-itantly, but unrelated to his infection, his leukocyte countdropped. Despite additional broad-spectrum antibiotic ther-apy, blood and wound cultures grew B. cereus, and a computed-tomography scan revealed signs of a damaged blood-brainbarrier potentially compatible with toxic encephalitis. Threedays after the initial injury, the patient died due to respiratoryarrest. In the first case, the isolation of B. cereus from a throatculture was not considered serious, while in the second case,the visualization of “large Gram-positive rods on smear of thewound exudate” was interpreted as a Clostridium species, andpenicillin was administered to the patient, which the authorslater realized was ineffective against the prodigious �-lacta-mase-producing B. cereus. In a scenario somewhat reminiscentof the case described above, Groschel et al. (58) reported acase of a 35-year-old patient with a histocytic lymphoma inremission receiving chemotherapy who developed a fulminantgas gangrene-like infection of the hand. The hand infectiondeveloped a few hours after the patient hit his right hand witha wrench while working on his car. His white blood cell (WBC)count was 1,200 cells/mm3 at the time of the injury. Uponadmission to the hospital, he was febrile, and his right hand wasdiffusely swollen with purplish discoloration of the fingers andthe dorsal and palmar surfaces. On the dorsum, there wereseveral bullae with serosanguinous drainage. Gram staining ofthe exudate showed Gram-positive rods (which later proved tobe B. cereus) with no leukocytes. The patient was initiallytreated with penicillin for suspected Clostridium perfringensinfection. Incision and drainage were undertaken, and when B.cereus was identified, penicillin was discontinued and lincomy-cin treatment was started, which resulted in clinical improve-ment. Nevertheless, because of extensive necrosis, the third,fourth, and fifth fingers were removed.

GAS GANGRENE-LIKE INFECTIONS

The second meningitis case described above introduces thecapacity of B. cereus to produce a clinical syndrome resemblingclostridial myonecrosis.

Johnson et al. (73) also presented a case of presumedclostridial myonecrosis in a 20-year-old marine who endureda crush injury to his left arm when he caught it between twotrain cars and sustained an incomplete amputation and acommuted fracture of the radius and ulna. Three days post-surgery, the patient appeared septic, and his left arm wasnotably increased in size, with slight crepitance and a brownwatery fluid oozing from the wound. Gram staining of su-perficial tissue revealed numerous Gram-positive andGram-variable rods without spores and a few WBCs, sug-gesting C. perfringens myonecrosis. The patient was taken tosurgery, where an above-the-elbow open amputation wasperformed because of a deteriorating clinical condition.Penicillin was administered, and the patient was begun on ahyperbaric-oxygen protocol for presumed C. perfringens-induced gangrene. When cultures grew B. cereus, antimicro-bial therapy was changed, and the hyperbaric protocol wasdiscontinued. An analogous case was described by Sada etal. (113), that of a diabetic patient with alcoholic hepatop-



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

athy who developed B. cereus fasciitis and myonecrosis. Thepatient was initially treated with penicillin on the basis ofthe presence of Gram-positive bacilli in smears of the lesion.After extensive debridement twice, on the third hospitalday, a culture of the lesion grew B. cereus (“despite theinitial expectation”), which prompted an immediate switchfrom penicillin to vancomycin, with gradual improvement.The patient was discharged on the 94th hospital day afterseveral debridement and skin graft operations. Perhaps, thetakeaway lesson here is that one should render antibioticcoverage that would include activity against B. cereus (e.g.,vancomycin, clindamycin, and gentamicin) as well as againstClostridium species until the identification of the Gram-positive bacillus is achieved. To further stress the necessityfor an early differentiation of the two bacillary species, Dar-bar et al. (35) described a gas gangrene-like necrotizinginfection due to B. cereus in an 8-year-old boy after a smalltree branch pierced the child’s left leg. Blistering developedabove the wound, and crepitus was detected. The potentialfor B. cereus to mimic clostridial myonecrosis or even strep-tococcal necrotizing fasciitis should be considered when apatient presents with either of these suspected soft-tissueinfections. The mimicry of B. cereus myonecrosis comparedto that caused by C. perfringens may in part be attributed tophospholipase activity, which in C. perfringens accounts forincreased capillary permeability, platelet aggregation, he-molysis, and myonecrosis (48), all attributes described for B.cereus-induced myonecrosis (58).

In reviewing B. cereus gas gangrene-like infections, I wastroubled by the fact that B. cereus, in contrast to C. perfringens(which ferments carbohydrates in muscle tissue and producesgases, CO2 and H2 [93]), is anaerogenic with regard to fer-mentable carbohydrates (89; my unpublished data). This trou-bling dilemma, however, may have been solved by an intensiveliterature search, which uncovered a reported Fitzpatrick et al.(47), which also included P. C. B. Turnbull, a renowned experton microorganisms of the family Bacillaceae, especially B.cereus, as an author (129, 130, 131, 132). In this report of twogas gangrene-like infections due to B. cereus from 1979, thoseauthors also recognized that B. cereus “does not produce gas toany obvious extent in routine laboratory tests.” The authorsoffered, however, “that the production of gas during anaerobicreduction of nitrate is a characteristic of B. cereus.” It wassuspected that the gas was nitrogen, and I undertook anothersearch under the definition of denitrification, which renderedthe following finding: the formation of the gases nitrogenand/or other oxides of nitrogen from nitrate to nitrite by cer-tain bacteria during anaerobic respiration. Denitrification oc-curs only under anaerobic or microaerophilic conditions, whenthere is a sufficient amount of organic carbons to support thereaction. From personal experience, this concept may be rel-evant, as mixed B. cereus and C. perfringens infection may occurfollowing traumatic accidents involving soil and water contami-nation. A review by Bessman and Wagner (19) described 48 casesof nonclostridial “gas infection” in diabetic patients with or with-out gangrene caused by members of the family Enterobacteriaceaealone or in combination with anaerobes (Bacteroides fragilis) andEnterococcus species. There again, those authors stressed thatrapid diagnosis is critical since appropriate antibiotic therapy andsurgery can result in low mortality rates.

DIFFERENTIATION OF B. CEREUS FROMC. PERFRINGENS

Case Vignette

Several years ago a 21-year-old patient was transferred tothe Mount Sinai Hospital (New York, NY) with a diagnosisof gas gangrene subsequent to an automobile accident inwhich he was trapped under his vehicle in a body of muddywater. Gram-stained smears of the involved leg revealedGram-positive rods (Fig. 8), which grew beta-hemolytic col-onies aerobically and anaerobically upon culture and whenisolated and identified proved to be those of B. cereus and C.perfringens. As the patient’s course did not improve despitehyperbaric therapy and antibiotic treatment, he was taken tothe operating room for disarticulation of the infected leg.Prior to surgery, however, the surgeons submitted a piece ofnecrotic tissue to determine if “Clostridium perfringens wasstill present in the wound.” A Gram stain smear of a touchimprint of the tissue specimen showed Gram-positive bacilli.In view of the presence of two morphologically similar ba-cilli in the original smears and cultures, the issue of answer-ing the surgeon’s question was daunting. To differentiatebetween the two bacillary forms, an India ink preparation(as outlined in the legend of Fig. 9) was performed, whichrevealed the presence of encapsulated bacilli consistent withC. perfringens. This information was relayed to the surgeonsawaiting a response in the operating room, who then under-took their surgical procedure. The following day, a cultureof the necrotic tissue grew only C. perfringens. A rapid dif-ferentiation between B. cereus gangrene-like myonecrosisfrom C. perfringens myonecrosis can be achieved initially byperforming an India ink test directly with a tissue samplefrom the wound. The absence of capsules suggests infectionwith B. cereus or perhaps a non-C. perfringens clostridialspecies, which nevertheless should indicate antibiotic cover-age for B. cereus while awaiting culture results.

CUTANEOUS INFECTIONS DUE TO TRAUMA

For patients who suffer bodily trauma, whether by penetrat-ing objects or as a consequence of burns or motor vehicle-

FIG. 8. Gram-positive uniform bacilli in a smear of a myonecrosislesion that grew B. cereus and C. perfringens.



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

related trauma, infection remains a leading cause of death.Depending upon the environment in which the trauma takesplace, e.g., fresh or salt water or soil, recognized microbialspecies such as Pseudomonas aeruginosa or Aeromonas orVibrio species predominate (107), whereas Bacillus species iso-lated from trauma-induced wounds, whether water related ornot, are usually regarded as contaminants and basically ignoreduntil a more dramatic complication such as, for example, sepsisor necrotizing fasciitis occurs and is attributed to the bacillaryspecies. In recent years, however, the recognition of B. cereusas a major pathogen infecting individuals who sustain trau-matic injuries is being well documented (2, 22, 42, 81, 107).Because of the wide environmental distribution of B. cereusspores, especially in soil, they can easily disseminate throughdust, water, and food. A consequence of this widespread dis-persion is open-wound infections, whether postsurgical (2) orposttraumatic, e.g., gun shot wounds (81), injection drug abuse(22), ground-contracted open-wound fractures (138), and se-vere war wounds (65), which may occur in both immunocom-petent and immunosuppressed individuals, while infections re-sulting from hematogenous dissemination are more likely tooccur in the setting of immunosuppression. Risk factors forthese cases include mainly articulation with soil and water inaddition to contaminated medicinals such as insulin (100) andheroin (22) in the setting of drug abuse among other injection-administered medicinals. Wound contamination with B. cereuscan take place at the time of initial trauma due to the ubiqui-tous presence of B. cereus spores in the environment. Alterna-tively, the capacity of B. cereus spores to persist in plaster-impregnated gauze (112), incontinence pads, and hospitallinen (11, 12) as well as in many antiseptics such as chlorhexi-dine, povodone iodine, and alcohol (42, 69) facilitates thisbacterium’s capacity to function as a secondary nosocomialinvader of sites of traumatic injury (Table 1).

PRIMARY CUTANEOUS INFECTIONS

From the data reviewed above, it is apparent that B. cereusinfections predominate in immunosuppressed patients, whileprimary cutaneous infections may occur in both immunosup-pressed (58, 63, 76) and nonimmunosuppressed individuals,with the latter usually being associated with traumatic incidents(2, 22, 42, 65).

In a review of culture reports for children with neutropeniccancer treated at St. Jude Children’s Research Hospital from1983 to 1988, Henrickson et al. (62) reported 10 cases of B.cereus primary cutaneous infections in the absence of positiveblood culture results. The lesions, which developed mainly onthe extremities, e.g., finger, toe, and limb, were initially vesic-ular and then became purulent with rapidly spreading cellulitis.In no instance did the affected patients have signs of or historyof injury to the skin. The review revealed that all 10 infectionsoccurred during the spring and summer months, drawing ananalogy to B. anthracis cutaneous infections of children in theGambia (West Africa), which have a predominance in the dry(November to May) season and persist through the rainymonths of June, July, and August (66). B. anthracis sporessurvive in uncultivated soil and at ambient temperatures above15°C, similar to conditions of the lower Mississippi valley.Those authors then speculated that B. cereus spores, which arewidespread in soil, may be common in the hospital (Memphis,TN) environment. Spores of B. cereus may enter the skin ofhands and feet, which are often in contact with the environ-ment through microscopic skin abrasions (Fig. 10), as dospores of B. anthracis (63, 66). Clinically, the evolving skinlesions of B. anthracis infection start with a papule, whichbecomes serous or serosanguinous and develops a black escharthat is similar to some of the B. cereus skin lesions described byHenrickson et al. (62). The elaboration of the various B. cereusexotoxins, including dermonecrotic toxin, may well account foreschar production in B. cereus cutaneous infections (13).

On the heels of the publication by Henrickson was a reportby Dryden and Kramer (41), who described primary cutaneousinfections among 21 healthy individuals, 18 to 27 years of age,undertaking an expedition in a remote rain forest in Costa

FIG. 9. India ink preparation of exudate from a gangrenous lesionshowing encapsulated bacilli, which allowed the differentiation of C.perfringens from B. cereus. The smear was prepared by emulsifyingfragments of necrotic tissue in India ink and smearing contents withanother glass slide across the prepared slide. After drying, crystal violetwas applied to the slide, and the slide was rinsed gently, air dried, andexamined under oil immersion.

FIG. 10. Rapidly spreading erythematous cellulitis in a 17-year-oldpatient following a puncture wound to sole of the foot while walkingbarefoot in a garden. Aspiration of spreading erythema grew B. cereus.Note the site of puncture on the heel of the foot.



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

Rica, Central America. Infections developed almost exclu-sively on the extremities following multiple lacerations frominjury by rocks, thorns, machetes, and mosquito and tick bitesand one following an attack by a wild peccary (pugnacioushog-like ungulate). Of 36 wound specimens cultured, B. cereuswas isolated from 30 cultures, 24 of which resulted in heavygrowth. Altogether, 14 of 18 expedition members developed B.cereus infections, while the remaining 3 patients developedStreptococcus pyogenes cutaneous infections. B. cereus was alsorecovered from 15 nose swabs and five throat swabs, which ismost likely due to the fact that “expedition members werecontinuously covered in dust and dirt throughout the 6 weeksin the jungle.” Sixteen of the strains were prodigious producersof one or more exotoxins having necrotic activity, a findingcorrelating with the clinical presentation of pyoderma withsurrounding cellulitis.

ENDOCARDITIS

The rarity of a B. cereus infection of the heart of a drugaddict was documented in an almost obscure letter by Craig etal. (34), who vividly penned the course of endocarditis in an18-year-old girl who was a heroin addict and had an atrialseptal defect. Upon admission, numerous needle tracks werepresent, but no petechiae or retinal hemorrhage was apparent.Because of abnormal cardiac sounds and elevated leukocytecounts, blood cultures were drawn upon admission, and duringthe next 4 days, all of them grew B. cereus. Those authorssuspected that tricuspid-valve endocarditis was induced duringself-administration of drugs. Despite some early setbacks withinappropriate antibiotic treatment, e.g., penicillin, the patientresponded well to intravenous clindamycin. Later studies ofbacteremia in drug addicts incriminated heroin and contami-nated injection paraphernalia (84, 127, 137) as risk factors inaddition to cardiac anomalies.

Since that early description, B. cereus endocarditis in drugaddicts and in patients with an intravascular device has beenwell recognized. In a review of B. cereus by Steen et al. (123),they noted that the rates of morbidity and mortality associatedwith B. cereus endocarditis were high among patients withvalvular heart disease (20, 29, 105, 121). In the course of theirreview, those authors noted that 10 cases of endocarditis hadbeen previously reported: 6 were drug addicts (including thatreported by Craig et al.), 1 had a pacemaker, and the remain-ing cases had valvular disease. Since that review was published,several more case reports of B. cereus endocarditis in the set-ting of patients with pacemakers (1, 121), two cases of infectionof a prosthetic mitral valve (20, 29), and two cases underremarkable circumstances (32, 126) have surfaced. The firstcase (126) was that of a 12-month-old girl with no past medicalhistory who presented with bloody diarrhea attributable toulcerative colitis that was later complicated by B. cereus endo-carditis and cerebral infarctions (not necessarily related toendocarditis). In this instance, there were two factors that mayhave contributed to B. cereus sepsis and endocarditis. Initially,colonic endoscopy and biopsy specimens showed a swollenreddened mucosa with multiple erosions and a prodigious in-filtration of inflammatory cells and microabscesses in thecrypts. Although the presence of microorganisms was not com-mented upon in that report, invasion of B. cereus through the

disrupted mucosa could have taken place, with food as thesource of the bacterium. The second risk factor was the ad-ministration of betamethasone suppositories, which was fol-lowed by high fever and marked leukocytosis.

The second case, reported by Cone et al. (32), is noteworthyin that it possessed many of the above-described issues asso-ciated with B. cereus infections in immunosuppressed individ-uals. The patient was a 38-year-old male farm worker (risk 1)with relapsing acute lymphoblastic leukemia (risk 2) who de-veloped spontaneously an ulcerating ulcer on his anteriorthigh, which was surrounded by a nontender area of erythemafrom which B. cereus was isolated concomitant with a positiveblood culture. After 2 weeks of intravenous therapy (penicillinand vancomycin) and, later, therapy with gatifloxacin orally,the patient received chemotherapy (risk 3), which a day laterled to neutropenic B. cereus bacteremia. The patient expired 3days later. At autopsy, the patient was found to have acute mitral-valve endocarditis and bilateral brain abscesses. Because the de-velopment of his cutaneous lesion was followed by sepsis, thoseauthors likened his infection to that of B. anthracis.

With the exception of intravenous drug abuse-associated B.cereus endocarditis, the source of the microorganism in manycases is somewhat occult. In patients with an inserted pace-maker or prosthetic valve in place, one may speculate thatasymptomatic B. cereus bacteremia could induce endocarditis.Alternatively, the repeated use of a venipuncture site for hep-arin injections could be the venue for introducing B. cereus intothe bloodstream. In one instance the site was reported to beswollen and tender, which was attributable to the developmentof thrombophlebitis (29). Other possibilities include B. cereusinvasion of the gastrointestinal tract under appropriate condi-tions, as outlined above, and, through hematological spread,colonization of a susceptible cardiac valve.

OSTEOMYELITIS

Bone infections by B. cereus are somewhat rare, and as of1994, only nine cases were uncovered by Schricker et al. (117)in their review of this topic. Most of the cases were not re-ported individually but, rather, were included as part of reviewsof the spectrum of B. cereus infections (45, 121, 128). B. cereusosteomyelitis in these patients was associated with intravenousdrug addiction and surgical trauma, in addition to two individ-uals not included in the review who had sustained motor ve-hicle trauma prior to developing B. cereus osteomyelitis (138).Infections were either monobacterial or mixed with anothercopathogen, e.g., Staphylococcus aureus (117). In no instancewas a case of B. cereus osteomyelitis documented in the ab-sence of one or more of the above-described risk factors, e.g.,in addition to alcohol abuse or sickle cell-thalassemia disease(122).

URINARY TRACT INFECTIONS

A PubMed search of the literature revealed one docu-mented case of B. cereus urinary tract infection in a 71-year-oldwoman with invasive bladder cancer (115). The patient under-went radical cystectomy and percutaneous left ureterostomy,after which an indwelling urethral catheter was placed, alongwith treatment with cephalosporin and other antibiotics. Five



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

weeks postoperatively, she presented with fever, shaking chills,and pyuria and was diagnosed with pyelonephritis of the leftkidney. A urine culture grew B. cereus, which those authorssuspected colonized the catheter and ascended into the urinarysystem through ureterostomy irrigation, which was performedseveral times daily. Among the virulence mechanisms of B.cereus pathogenesis, adherence to catheters via biofilm forma-tion and motility could have easily accounted for the ascensionof the bacterium into the urinary tract. Occult listings of B.cereus urinary tract infections have also cited instrumentationas a prelude to infection (128).

ANTIBIOTIC SUSCEPTIBILITY

The clinical spectrum of B. cereus infections is multifaceted,and therapeutic options usually revolve around the antibioticsusceptibility pattern of the isolated strain. In general, most B.cereus isolates are resistant to penicillins and cephalosporins asa consequence of �-lactamase production. In the setting of asuspected B. cereus infection, empirical therapy may be neces-sary while awaiting the antibiotic susceptibility testing profile.Resistance of B. cereus to erythromycin, tetracycline, and car-bapenem has been reported (77, 116), which may complicatethe selection of an empirical treatment choice. To address thisissue, several investigators have undertaken in vitro suscepti-bility studies utilizing various methodologies to provide someguidance while awaiting isolate-specific susceptibility data.

An early study of 54 B. cereus strains isolated from bloodcultures (15 judged significant [23 possibly significant]) con-ducted in 1988 by Weber et al. (136) showed that all strainstested by microdilution were susceptible to imipenem, vanco-mycin, chloramphenicol, gentamicin, and ciprofloxacin. Moststrains were resistant to clindamycin, cefazolin, and cefo-taxime. Many strains were susceptible to erythromycin andtetracycline. Using National Committee for Clinical Labora-tory Standards (NCCLS) breakpoints for aerobic bacteria (103,104), microdilution and disk diffusion susceptibility testingshowed that data collected by disk diffusion correlated withmicrodilution results showing that all B. cereus isolates wereresistant to penicillins (except mezlocillin), oxacillin, and ceph-alosporins. Clavulanic acid combined with ticarcillin did notlead to increased activity. Based on their data, those authorsstated that “the drug of choice for B. cereus infections appearsto be vancomycin” and that broad-spectrum cephalosporinsand ticarcillin-clavulanate should be avoided in the empiricaltreatment of patients with suspected B. cereus infection.

With the advent of the Etest, in 2004, Turnbull et al. (132)reported their results for MICs of selected antibiotics against67 B. cereus strains implicated in nongastrointestinal infections(21) and food poisoning (15) and from the environment (31).With this selection of isolates, those authors thought the re-sults would give the greatest guidance for initial empiricaltherapy of B. cereus infections. For comparison, 15 of the B.cereus strains were also tested by using an agar dilutionmethod. An analysis of the results for the different categoriesof B. cereus isolates did not reveal any group trends. From theauthors’ data, and quoting many case reports of B. cereusinfections, they concluded that resistance to penicillin, ampi-cillin, cephalosporins, and trimethoprim is constant, while sus-ceptibility to clindamycin, erythromycin, chloramphenicol, van-

comycin, the aminoglycosides, and tetracycline is usuallyobserved. Susceptibility to ciprofloxacin was uniform, and ithas been shown to be highly effective in the treatment of B.cereus wound infections (132).

Luna et al. (90) tested 42 B. cereus isolates by Sensititre andEtest methods and reported results similar to those reportedabove (132, 136). In the final analysis in each of the reportedstudies, small populations of B. cereus isolates showed resis-tance to clindamycin, erythromycin, and trimethoprim-sulfa-methoxazole. Regarding newer antibiotics, Luna et al. (90)extended their spectrum of therapeutic/prophylactic antimicro-bials, which included gatifloxacin, levofloxacin, moxifloxacin,rifampin, daptomycin, and linezolid, to which all 42 isolateswere 100% susceptible.

CONCLUSIONS

There is no conclusion to the saga of human infections dueto B. cereus. Despite their supposed “rare occurrence,” therecognition of this seemingly stealth, environmentally perva-sive bacterium coexisting with human flora is indeed a “Tale ofTwo Cities.” On the one hand, the bacterium has evolved apanoply of virulence-related attributes such as adhesins andtoxins that enable its entry and survival within the human hostand, under appropriate circumstances, enable it to breach bar-riers to produce disease in various anatomical compartments.

The major hurdle in evaluating its presence when isolatedfrom a clinical specimen is overcoming its nagging stigmata asan “insignificant contaminant,” which is still in vogue despite aglobally ongoing documentation of extraintestinal infections.

Indeed, outside the notoriety of B. cereus in association withfood poisoning and eye infection, recognition and appreciationfor the multitude of other serious infections such as fulminantsepsis and devastating central nervous system infections arelacking. The suspicion of the association of B. cereus with thesemounting infectious complications moves with a fatal lethargyin its recognition as a bona fide human pathogen. Cliniciansand clinical microbiologists must both give serious consider-ation to the significance of a B. cereus isolate from a clinicalspecimen, especially if the patient is immunosuppressed.

B. cereus, by virtue of its extensive exoenzyme armamentar-ium, is centrally situated between B. anthracis and, althoughanaerobic, C. perfringens, forming a formidable link enjoiningthese spore-forming bacterial species. B. cereus can acquireand harbor B. anthracis genes producing anthrax-like pulmo-nary infections and, through its exoenzyme profile, some ofwhich overlaps with that of C. perfringens, causing gas gan-grene-like cutaneous infections.

While B. cereus engenders clinical presentations that coin-cide with those of its close bacterial relatives, its extraintestinalspectrum of human infections, as noted herein, exceeds thoseattributed to the two more-renowned bacterial species. Onecan envision B. cereus as a biblical Sampson, arms spreadbetween two pillars, embracing rather than undoing a commonbond! Perhaps, by the time a new review of B. cereus is penned,the bacterium would have acquired its acceptance as a volatilehuman pathogen, quiescent in nature yet a formidable humanadversary!



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

ACKNOWLEDGMENTS

I extend my sincere gratitude to Dipankar Jyoti Dutta, James Vis-kochil, and Christopher Marro for their computer expertise in assistingme with the formatting of the manuscript.

REFERENCES

1. Abusin, S., A. Bhimaraj, and S. Khadra. 2008. Bacillus cereus endocarditisin a permanent pacemaker: a case report. Cases J. 1:95.

2. Akesson, A., S. A. Hedstrom, and T. E. Ripa. 1991. Bacillus cereus: asignificant pathogen in postoperative and post-traumatic wounds in ortho-paedic wards. Scand. J. Infect. Dis. 23:22–30.

3. Akiyama, N., K. Mitani, Y. Tanaka, Y. Hanazono, N. Motoi, M. Zarkovic,Y. Tange, H. Hirai, and Y. Yazaki. 1997. Fulminant septicemic syndrome ofBacillus cereus in a leukemic patient. Int. Med. 36:221–226.

4. Allison, C., N. Coleman, P. L. Jones, and C. Hughes. 1992. Ability of Proteusmirabilis to invade human uroepithelial cells is coupled to motility andswarming differentiation. Infect. Immun. 60:4740–4746.

5. Anderson, A., P. E. Granum, and U. Ronner. 1998. The adhesion of Bacilluscereus spores to epithelial cells might be an additional virulence mechanism.Int. J. Food Microbiol. 39:93–99.

6. Arnaout, M. K., R. T. Tamburro, S. M. Bodner, J. T. Sandlund, G. K.Rivera, C. H. Pui, and R. C. Ribeiro. 1999. Bacillus cereus fuliminant sepsisand hemolysis in two patients with acute leukemia. J. Pediatr. Hematol.Oncol. 21:431–435.

7. Arnesen, L. P. S., A. Fogerlund, and P. E. Granum. 2008. From soil to gut:Bacillus cereus and its food poisoning toxins. FEMS Microbiol. Rev. 32:579–606.

8. Ash, C., J. A. Farrow, M. Dorsch, E. Stackenbrandt, and M. D. Collins.1991. Comparative analysis of Bacillus anthracis, Bacillus cereus, and relatedspecies on the basis of reverse transriptase of 16S rRNA. Int. J. Syst.Bacteriol. 41:343–346.

9. Auger, S., N. Ramarao, C. Faille, A. Fouet, S. Aymerich, and M. Gohar. 31July 2009. Biofilm formation and cell surface properties among pathogenicand nonpathogenic strains of the Bacillus cereus group. Appl. Environ.Microbiol. doi:10.1128/AEM.00155-09.

10. Avashia, S. B., W. S. Wiggens, C. Lindley, A. H. Hoffmaster, R. Drumgoole,T. Nekomoto, P. J. Jackson, K. K. Hill, K. Williams, L. Lehman, M. C.Libal, P. P. Wilkins, J. Alexander, A. Tvaryanas, and T. Betz. 2007. Fatalpneumonia among metalworkers due to inhalation exposure to Bacilluscereus containing Bacillus anthracis toxin genes. Clin. Infect. Dis. 44:414–416.

11. Barrie, D., J. A. Wilson, P. N. Hoffman, and J. M. Kramer. 1992. Bacilluscereus meningitis in two neurological patients: an investigation into thesource of the organism. J. Infect. 25:291–297.

12. Barrie, D., P. N. Hoffman, J. A. Wilson, and J. M. Kramer. 1994. Contam-ination of hospital linen by Bacillus cereus. Epidemiol. Infect. 113:297–306.

13. Beecher, D. J., J. L. Schoeni, and A. C. L. Wong. 1995. Enterotoxic activityof hemolysin BL from Bacillus cereus. Infect. Immun. 63:4423–4428.

14. Beecher, D. J., J. S. Pulido, N. P. Barney, and A. C. L. Wong. 1995.Extracellular virulence factors in Bacillus cereus endophthalmitis: methodsand implication of involvement of hemolysin BL. Infect. Immun. 63:632–639.

15. Beecher, D. J., T. W. Olsen, E. B. Somers, and A. C. L. Wong. 2000.Evidence for contribution of tripartite hemolysin BL, phosphatidylcholine-preferring phospholipase C, and collegenase to virulence of Bacillus cereusendophthalmitis. Infect. Immun. 68:5269–5276.

16. Berger, S. A. 1983. Pseudobacteremia due to contaminated alcohol swabs.J. Clin. Microbiol. 18:974–975.

17. Berkeley, R. C. W., N. A. Logan, L. A Shute, and A. G. Capey. 1984.Identification of Bacillus species, p. 291–328. In T. Bergen (ed.), Methodsin microbiology, vol. 16. Academic Press, London, United Kingdom.

18. Berman, E. R. 1991. Biochemistry of the eye. Plenum Press, New York, NY.19. Bessman, A. N., and W. Wagner. 1975. Nonclostridial gas gangrene. Report

of 48 cases and review of the literature. JAMA 42:958–963.20. Block, C. S., M. L. Levy, and V. U. Fritz. 1978. Bacillus cereus endocarditis.

S. Afr. Med. J. 53:556–557.21. Bouza, E., S. Grant, M. C. Jordan, R. W. Yook, and H. L. Sulit. 1979.

Bacillus cereus endogenous panophthalmitis. Arch. Ophthalmol. 97:498–499.

22. Brett, M. M., J. Hood, J. S. Brazier, B. I. Duerden, and J. M. Hahne. 2005.Soft tissue infections by spore-forming bacteria in injecting drug users in theUnited Kingdom. Epidemiol. Infect. 133:575–582.

23. Bryce, E. A., J. A. Smith, M. Tweeddale, B. J. Andruschak, and M. R.Maxwell. 1993. Dissemination of Bacillus cereus in an intensive care unit.Infect. Control Hosp. Epidemiol. 14:459–462.

24. Callegan, M. C., M. C. Booth, B. D. Jett, and M. S. Gilmore. 1999. Patho-genesis of Gram-positive bacterial endophthalmitis. Infect. Immun. 67:3348–3356.

25. Callegan, M. C., B. D. Jett, L. E. Hancock, and M. S. Gilmore. 1999. Roleof hemolysin BL in the pathogenesis of extraintestinal Bacillus cereus in-

fections as assessed in an endophthalmitis model. Infect. Immun. 67:3357–3366.

26. Callegan, M. C., M. Engelbert, D. W. Parke II, B. D. Jett, and M. S.Gilmore. 2002. Bacterial endophthalmitis: epidemiology, therapeutics, andbacterium-host interactions. Clin. Microbiol. Rev. 15:111–124.

27. Callegan, M. C., B. D. Novasad, R. Ramirez, G. Ghelardi, and S. Senesi.2006. Role of swarming migration in the pathogenesis of Bacillus endoph-thalmitis. Invest. Ophthalmol. Vis. Sci. 47:4461–4467.

28. Callegan, M. C., D. C. Cochran, R. T. Ramadan, J. Chodosh, C. McLean,and D. W. Stroman. 2006. Virulence factor profiles and antimicrobial sus-ceptibilities of ocular Bacillus isolates. Curr. Eye Res. 31:693–702.

29. Castedo, E., A. Castro, P. Martin, J. Roda, and C. G. Montero. 1999.Bacillus cereus prosthetic valve endocarditis. Ann. Thorac. Surg. 68:2351–2352.

30. Chen, M., P. K. Hou. T. U. Tai, and B. J. Lin. 2008. Blood-ocular barriers.Tzuchi Med. J. 20:25–34.

31. Colpin, G. G. D., H. F. L. Guiot, R. F. A. Simonis, and E. E. Zwann. 1981.Bacillus cereus meningitis in a patient under gnotobiotic care. Lancet ii:694–695.

32. Cone, L. A., L. Dreisbach, B. E. Potts, B. E. Comess, and W. A. Burleigh.2005. Fatal Bacillus cereus endocarditis masquerading as an anthrax-likeinfection in a patient with acute lymphoblastic leukemia: case report.J. Heart Valve Dis. 14:37–39.

33. Costerton, J. W., P. S. Stewart, and E. P. Greenberg. 1999. Bacterialbiofilms: a common cause of persistent infection. Science 284:1318–1322.

34. Craig, C. P., W.-S. Lee, and M. Ho. 1974. Bacillus cereus endocarditis in anaddict. Ann. Intern. Med. 80:418–419.

35. Darbar, A., I. A. Harris, and I. B. Gosbell. 2005. Necrotizing infection dueto Bacillus cereus mimicking gas gangrene following penetrating trauma.J. Orthop. Trauma 19:353–355.

36. Davenport, R., and C. Smith. 1952. Panophthalmitis due to an organism ofthe Bacillus subtilis group. Br. J. Ophthalmol. 36:389–392.

37. David, R. B., G. R. Kkirkby, and B. A. Noble. 1994. Bacillus cereus endoph-thalmitis. Br. J. Ophthalmol. 78:577–580.

38. Dohmae, S., T. Okubo, W. Higuchi, T. Takano, H. Isobe, T. Baranovich, S.Kobayashi, M. Uchiyama, T. Tanabe, M. Itoh, and T. Yamamoto. 2008.Bacillus cereus nosocomial infection from reused towels in Japan. J. Hosp.Infect. 69:361–367.

39. Donzis, P. B., B. J. Mondino, and B. A. Weisman. 1988. Bacillus keratitiswith contaminated contact lens case system. Am. J. Ophthalmol. 105:195–197.

40. Drobniewski, F. A. 1993. Bacillus cereus and related species. Clin. Micro-biol. Rev. 6:324–338.

41. Dryden, M. S., and J. M. Kramer. 1987. Toxigenic Bacillus cereus as a causeof wound infections in the tropics. J. Infect. 15:207–212.

42. Dubouix, A., E. Bonnet, M. H. Bensafi, M. Archambaud, B. Chaminade, G.Echabanon, and N. Marty. 2005. Bacillus cereus infections in traumatologyorthopedics department: retrospective investigation and improvement ofhealth practices. J. Infect. 50:22–30.

43. Eberl, L., G. Christiansen, S. Molin, and M. Givskov. 1996. Differentiationof Serratia liquefaciens into swarm cells is controlled by expression of theflhD master operon. J. Bacteriol. 178:554–559.

44. El Saleeby, C. M., S. C. Howard, R. T. Hayden, and J. A. McCullers. 2004.Association between tea ingestion and invasive Bacillus cereus infectionamong children with cancer. Clin. Infect. Dis. 39:1536–1539.

45. Farrar, W. E. 1963. Serious infections due to “non-pathogenic” organismsof the genus Bacillus. Am. J. Med. 34:134–141.

46. Ferencz, J. R., E. I. Assia, L. Diamantstein, and E. Rubinstein. 1999.Vancomycin concentration in the vitreous after intravitreal administrationfor post operative endophthalmitis. Arch. Ophthalmol. 117:1023–1027.

47. Fitzpatrick, D. J., P. C. Turnbull, C. T. Keane, and L. F. English. 1979. Twogas-gangrene-like infections due to Bacillus cereus. Br. J. Surg. 66:577–579.

48. Flores-Diaz, M., and A. Alape-Giron. 2008. Role of Clostridium perfringensphospholipase C in the pathogenesis of gas gangrene. Toxicon 42:979–986.

49. Foster, J. R., J. A. Martinez, T. G. Murray, P. E. Rubsamen, H. W. Flynn,and R. K. Foster. 1996. Useful visual outcomes after treatment of Bacilluscereus endophthalmitis. Ophthalmology 103:390–397.

50. Funada, H., C. Votani, T. Machi, T. Matsuda, and A. Nonomura. 1988.Bacillus cereus bacteremia in an adult with acute leukemia. Jpn. J. Clin.Oncol. 18:69–74.

51. Gaur, A. H., C. C. Patrick, J. A. McCullers, P. A. Flynn, T. A. Pearsons, B. I.Razzouk, S. J. Thompson, and J. L. Shenep. 2001. Bacillus cereus bactere-mia and meningitis in immunocompromised children. Clin. Infect. Dis.32:1456–1462.

52. Ghelardi, E., F. Celandroni, S. Salvetti, M. Ceragoli, D. J. Beecher, S.Senesi, and A. C. L. Wong. 2007. Swarming behavior of and hemolysinsecretion by Bacillus cereus. Appl. Environ. Microbiol. 73:4089–4093.

53. Ghosh, A. C. 1978. Prevalence of Bacillus cereus in the faeces of healthyadults. J. Hyg. (Lond.) 80:233–236.

54. Girsch, M., M. Ries, M. Zenker, R. Carbon, A. Rauch, and M. Hofbeck.2003. Intestinal perforation in a premature infant caused by Bacillus cereus.Infection 31:192–193.



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

55. Goldstein, B., and E. Abrutyn. 1985. Pseudo-outbreak of Bacillus speciesrelated to fiberoptic bronchoscopy. J. Hosp. Infect. 6:194–200.

56. Granum, P. E. 1994. Bacillus cereus and its toxins. J. Appl. Bacteriol. Symp.Suppl. 76:615–665.

57. Greenwald, M. J., L. G. Wohl, and C. H. Sell. 1986. Metastatic bacterialendophthalmitis: a contempory reappraisal. Surv. Ophthalmol. 31:81–101.

58. Groschel, M., A. Burges, and G. P. Bodey. 1976. Gas gangrene-like infectionwith Bacillus cereus in a lymphoma patient. Cancer 37:988–991.

59. Grossniklaus, H., H. Bruner, W. E. Frank, and E. W. Purnell. 1985. Bacilluscereus panophthalmitis appearing as an acute glaucoma in a drug addict.Am. J. Ophthalmol. 100:334.

60. Guiot, H. F. L., M. M. de Planque, D. J. Richel, and J. W. Van’t Wout. 1986.Bacillus cereus: a snake in the grass for granulocytopenic patients. J. Infect.Dis. 153:1186.

61. Henrichsen, J. 1972. Bacterial surface translocation: a survey and classifi-cation. Bacteriol. Rev. 36:478–503.

62. Henrickson, K. J., P. M. Flynn, J. L. Shenep, and C. H. Pui. 1989. Primarycutaneous Bacillus cereus infections in neutropenic children. Lancet i:601–603.

63. Henrickson, K. J. 1990. A second species of Bacillus causing primarycutaneous disease. Int. J. Dermatol. 29:19–20.

64. Hernaiz, C., A. Picardo, J. I. Alos, and J. L. Gomez-Garces. 2003. Noso-comial bacteremia and catheter infection by Bacillus cereus in an immuno-competent patient. Clin. Microbiol. Infect. 9:973–975.

65. Hernandez, E., P. Dubrous, B. Deloynes, and J. D. Cavallo. 1996. Infectionsand superinfections due to Bacillus cereus following severe war injuries ofFrench soldiers in former Yugoslavia and the Gulf War, abstr. K-110.Abstr. 36th Intersci. Conf. Antimicrob. Agents Chemother. American So-ciety for Microbiology, Washington, DC.

66. Heyworth, B., M. E. Ropp, N. G. Voss, H. I. Meinel, and H. M. Darlow.1975. Anthrax in the Gambia: an epidemiological study. Br. Med. J.iv:79–82.

67. Hoffmaster, A. R., J. Ravel, D. A. Rasko, G. D. Chapman, M. D. Chute,C. K. Mariston, B. K. De, C. T. Sacchi, C. Fitzgerald, L. W. Mayer, M. C.Maiden, F. G. Priest, M. Barker, L. Jiang, R. Z. Cer, J. Rilstone, T. D. Reed,T. Popovic, and C. M. Fraiser. 2004. Identification of anthrax toxin genes inBacillus cereus associated with an illness resembling inhalation anthrax.Proc. Natl. Acad. Sci. U. S. A. 101:8449–8454.

68. Hoffmaster, A. R., K. H. Hill, D. J. E. Gee, C. H. Marston, B. K. De, T.Popovic, D. Sue, P. W. Wilkins, S. B. Avashia, R. Drumgoole, C. H. Helma,L. O. E. Ticknor, R. T. Okinaka, and P. J. Jackson. 2006. Characterizationof Bacillus cereus isolates associated with fatal pneumonias: strains areclosely related to Bacillus anthracis and harbor B. anthracis virulence genes.J. Clin. Microbiol. 44:3352–3360.

68a.Holt, J. G. 1994. Bergey’s manual of determinative biology. LippincottWilliams & Wilkins, Baltimore, MD.

69. Hsueh, P.-R., L.-J. Teng, P.-C. Yang, H.-L. Pan, S.-W. Ho, and K.-T. Luh.1999. Nosocomial pseudobacteremia caused by Bacillus cereus traced tocontaminated ethyl alcohol from a liquor factory. J. Clin. Microbiol. 37:2280–2284.

70. Ihde, D. C., and D. Armstrong. 1973. Clinical spectrum of infection due toBacillus species. Am. J. Med. 55:839–845.

71. Jensen, G. B., B. M. Hansen, J. Ellenberg, and J. Mahillon. 2003. Thehidden lifestyles of Bacillus cereus and relatives. Environ. Microbiol. 5:631–640.

72. Jenson, H. B., S. R. Levy, C. Duncan, and S. McIntosh. 1989. Treatment ofmultiple brain abscesses caused by Bacillus cereus. Pediatr. Infect. Dis. J.8:795–798.

73. Johnson, D. A., P. L. Aulicino, and J. G. Newby. 1984. Bacillus cereus-induced myonecrosis. J. Trauma 24:267–270.

74. Kawatani, E., Y. Kishikawa, C. Sankoda, N. Kuwahara, D. Mori, K. Osoe-gawa, E. Matsuishi, and H. Gondo. 2009. Bacillus cereus sepsis and sub-arachnoid hemorrhage following consolidation chemotherapy for acutemyelogenous leukemia. Rinsho Ketsueki 50:300–303. (In Japanese.)

75. Kerkenezov, N. 1953. Panophthalmitis after a blood transfusion. Br. J.Ophthalmol. 37:632–636.

76. Khavari, P. A., J. L. Bolognia, R. Eisen, S. C. Edberg, S. C. Grimshaw, andP. E. Shapiro. 1991. Periodic acid-Schiff-positive organisms in primarycutaneous Bacillus cereus infections. Arch. Dermatol. 127:543–546.

77. Kiyomizu, K., T. Yagi, H. Yoshida, R. Minami, A. Tanimura, T. Karasuno,and A. Hiraoka. 2008. Fuliminant septicemia of Bacillus cereus resistant tocarbapenem in a patient with biphenotypic acute leukemia. J. Infect. Che-mother. 14:361–367.

78. Kopel, A. C., P. E. Carvounis, and E. R. Holz. 2008. Bacillus cereus endoph-thalmitis following invitreous bevacizumab injection. Ophthalmic Surg. La-sers Imaging 39:153–154.

79. Kotiranta, A., M. Haapasalo, K. Kari, E. Kerosuo, I. Olsen, T. Sorsa, J. H.Meurman, and K. Lounatmaa. 1998. Surface structure, hydrophobicity,phagocytosis, and adherence to matrix proteins of Bacillus cereus cells withand without the crystalline surface protein layer. Infect. Immun. 66:4895–4902.

80. Kotiranta, A., K. Lounatmaa, and M. Haapasalo. 2000. Epidemiology andpathogenesis of Bacillus cereus infections. Microbes Infect. 2:189–198.

81. Krause, A., A. Freeman, P. A. Sisson, and O. M. Murphy. 1996. Infectionwith Bacillus cereus after close-range gunshot injuries. J. Trauma InjuryInfect. Crit. Care 41:546–547.

82. Kuroki, R., K. Kawakami, L. Qin, C. Kaji, K. Watanabe, Y. Kimura, C.Ishiguro, S. Tanimura, Y. Tsuchiya, I. Hamaguchi, M. Sakakura, S. Sak-abe, K. Tsuji, M. Inoue, and H. Watanabe. 2009. Nosocomial bacteremiacaused by biofilm-forming Bacillus cereus and Bacillus thuringiensis. Intern.Med. 48:791–796.

83. Lebessi, E., H. D. Dellagrammaticas, G. Antonaki, M. Foustoukou, and N.Iacovidou. 2009. Bacillus cereus meningitis in a term neonate. J. Matern.Fetal Neonatal Med. 22:458–461.

84. Lee, W., and M. Ho. 1974. Bacillus cereus endocarditis in an addict. Ann.Intern. Med. 80:418.

85. Le Scanff, J., J. I. Mohammedi, A. Thiebaut, O. Martin, L. Argaud, and D.Robert. 2006. Necrotizing gastroenteritis due to Bacillus cereus in an im-munocompromised patient. Infection 34:98–99.

86. Liu, P. Y., O. Ke, and S. Chen. 1997. Use of pulsed-field gel electrophoresisto investigate a pseudo-outbreak of Bacillus cereus in a pediatric unit.J. Clin. Microbiol. 35:1533–1535.

87. Liu, F., and A. K. H. Kwok. 2008. The efficacy of intravitreal vancomycinand dexamethasone in treatment of experimental Bacillus cereus endoph-thalmitis. Curr. Eye Res. 33:761–768.

88. Logan, N. A., and R. C. W. Berkeley. 1984. Identification of Bacillus strainsusing the API system. J. Gen. Microbiol. 130:1871–1882.

89. Logan, N. A., T. Popovic, and A. Hoffmaster. 2000. Bacillus and otheraerobic endospore-forming bacteria, p. 455–483. In P. R. Murray, E. J.Baron, J. H. Jorgensen, M. L. Landry, and M. A. Pfaller (ed.), Manual ofclinical microbiology, 9th ed. ASM Press, Washington, DC.

90. Luna, V. A., D. S. King, J. G. Gulledge, A. C. Cannons, P. T. Amuso, andJ. Cattani. 2007. Susceptibility of Bacillus anthracis, Bacillus cereus, Bacillusmycoides, Bacillus pseudomycoides and Bacillus thuringiensis to 24 antimi-crobials using Sensititre automated microbial dilution and Etest agar gra-dient diffusion methods. J. Antimicrob. Chemother. 60:555–567.

91. Lund, T., and P. E. Granum. 1997. Comparison of biological effect of twodifferent enterotoxin complexes isolated from three different strains ofBacillus cereus. Microbiology 143:3329–3336.

92. Lund, T., M.-L. DeBuyser, and P. E. Granum. 2000. A new cytotoxin fromBacillus cereus that may cause necrotic enteritis. Mol. Microbiol. 38:254–261.

93. MacLennan, J. D. 1962. The histotoxic clostridial infections of man. Bac-teriol. Rev. 26:177–276.

94. Maki, D. G. 1980. Through a glass darkly: nosocomial pseudoepidemics andpseudobacteremias. Arch. Intern. Med. 140:26–28.

95. Margulis, L., J. Z. Jorgensen, S. Dolan, R. Kolchinsky, F. A. Rainey, andS. C. Lo. 1998. The arthromitus stage of B. cereus: intestinal symbionts ofanimals. Proc. Natl. Acad. Sci. U. S. A. 95:1236–1241.

96. Marley, E. F., N. K. Saini, C. Venkatraman, and J. M. Orenstein. 1995.Fatal Bacillus cereus meningoencephalitis in an adult with myelogenousleukemia. South. Med. J. 88:969–972.

97. Martinez, M. F., T. Haines, M. Waller, D. Tingey, and W. Gomez. 2007.Probable occupational endophthalmitis. Arch. Environ. Occup. Health 62:157–160.

98. Masi, R. J. 1978. Endogenous endophthalmitis associated with Bacilluscereus bacteremia in a cocaine addict. Ann. Ophthalmol. 10:1367–1370.

99. Miller, J. M., J. G. Hair, M. Hebert, L. Hebert, and F. J. Roberts, Jr. 1997.Fulminating bacteremia and pneumonia due to Bacillus cereus. J. Clin.Microbiol. 35:504–507.

100. Montecalvo, M. A., C. J. Karmen, S. K. Alampur, D. J. H. Kauffman, andG. W. Wormser. 1993. Contaminated medicinal solutions associated withendophthalmitis. Infect. Dis. Clin. Pract. 2:199–202.

101. Motoi, N., T. Ishida, I. Nakano, N. Akiyama, K. Mitani, H. Hirai, Y. Yazaki,and R. Machinami. 1997. Necrotizing Bacillus cereus infection of the me-ninges without inflammatory reaction in a patient with acute myelogenousleukemia: a case report. Acta Neuropathol. 93:301–305.

102. Moyer, A. L., R. T. Ramadan, B. D. Novosad, R. Astley, and M. C. Collagen.2009. Bacillus cereus-induced permeability of the blood ocular barrier dur-ing experimental endophthalmitis. Invest. Ophthalmol. Vis. Sci. 50:3783–3793.

102a.Nanickam, N., A. Knorr, and K. L. Muldrew. 2008. Neonatal meningoen-cephalitis caused by Bacillus cereus. Pediatr. Infect. Dis. J. 27:843–845.

103. National Committee for Clinical Laboratory Standards. 1984. Performancestandards for antimicrobial disc susceptibility tests, 3rd ed. National Com-mittee for Clinical Laboratory Standards, Villanova, PA.

104. National Committee for Clinical Laboratory Standards. 1985. Methods fordilution antimicrobial susceptibility tests for bacteria that grow aerobically.National Committee for Clinical Laboratory Standards, Villanova, PA.

105. Oster, H. A., and T. Q. Kong. 1982. Bacillus cereus endocarditis involving aprosthetic valve. South. Med. J. 75:508–509.

106. Ozkocaman, V., T. Ozcelik, R. Ali, F. Ozkalemkas, A. Ozkan, C. Ozakin, H.Akalin, A. Ursavaws, F. Coskun, B. Ener, and A. Tunali. 2006. Bacillus spp.



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

among hospitalized patients with haematological malignancies: clinical fea-tures, epidemics and outcomes. J. Hosp. Infect. 64:169–176.

107. Ribeiro, N. F. F., C. H. Heath, J. Kierath, S. Rea, M. Duncan-Smith, andF. M. Wood. 6 June 2009, posting date. Burn wounds infected by contam-inated water: case reports, review of the literature, and recommendationsfor treatment. Burns [Epub ahead of print.] doi:10.1016/j.burns.2009.03.02.

108. Richards, V., P. van der Auwera, R. Snoeck, D. Daneau, and F. Meunier.1988. Nosocomial bacteremias caused by Bacillus species. Eur. J. Clin.Microbiol. Infect. Dis. 7:783–785.

109. Richardson, A. J., M. M. Rothburn, and C. Roberts. 1986. Pseudo-outbreakof Bacillus species: related to fibreoptic bronchoscopy. J. Hosp. Infect.7:208–210.

110. Romarao, N., and D. Lereclus. 2006. Adhesion and cytotoxicity of Bacilluscereus and Bacillus thuringiensis to epithelial cells are FlhA and PlcR de-pendent respectively. Microbes Infect. 8:1483–1491.

111. Ronner, U., U. Husmark, and A. Henrikson. 1990. Adhesion of Bacillusspores in relation to hydrophobicity. J. Appl. Bacteriol. 69:550–556.

112. Rutala, W. A., S. M. Saviteer, C. A. Thomann, and M. B. Wilson. 1986.Plaster-associated Bacillus cereus wound infection. A case report. Orthope-dics 9:575–577.

113. Sada, A., N. Misago, T. Okawa, Y. Narisawa, S. Ide, M. Nagata, and S.Mitsumizo. 2009. Necrotizing fasciitis and myonecrosis “synergistic necro-tizing cellulitis” caused by Bacillus cereus. J. Dermatol. 36:423–426.

114. Saki, C., T. Iuchi, A. Ishii, K. Kumagai, and T. Takagi. 2001. Bacillus cereusbrain abssesses occurring in severely neutropenic patients: successful treat-ment with antimicrobial agents, granulocyte colony-stimulating factor, andsurgical drainage. Int. Med. 40:654–657.

115. Sato, K., S. Ichiyama, M. Ohmura, M. Takashi, N. Agata, M. Ohta, and N.Nakashima. 1998. A case of urinary tract infection caused by Bacilluscereus. J. Infect. 36:247–248.

116. Savini, V., M. Favaro, C. Fontana, C. Catavitello, A. Balbinot, M. Talia, F.Febbo, and D. D’Antonio. 2009. Bacillus cereus heteroresistant to carbap-enems in a cancer patient. J. Hosp. Infect. 71:288–290.

117. Schricker, M. E., G. H. Thompson, and J. R. Schreiber. 1994. Osteomyelitisdue to Bacillus cereus in an adolescent: case report and review. Clin. Infect.Dis. 18:863–867.

118. Senesi, S., F. Celandroni, S. Scher, A. C. L. Wong, and E. Ghelardi. 2002.Swarming motility in Bacillus cereus and characterization of a fliY mutantimpaired in swarm cell differentiation. Microbiology 148:1785–1794.

119. Shamsuddin, D., C. V. Tuazon, C. Levy, and J. Curtin. 1982. Bacillus cereuspanophthalmitis: source of the organism. Rev. Infect. Dis. 4:97–103.

120. Simini, B. 1998. Outbreak of Bacillus cereus endophthalmitis in Rome.Lancet 351:1258.

121. Sliman, R., S. Rehm, and D. Shlaes. 1987. Serious infections caused byBacillus species. Medicine (Baltimore) 66:218–223.

122. Solny, M. N., G. R. Failing, and J. S. Borges. 1977. Bacillus cereus osteo-myelitis. Arch. Intern. Med. 137:401–402.

123. Steen, M. K., L. A. Bruno-Murtha, G. Chaux, H. Lazar, S. Bernard, and C.Sulis. 1992. Bacillus cereus endocarditis: report of a case and review. Clin.Infect. Dis. 14:945–946.

124. Strauss, R., A. Mueller, M. Wehlrt, D. Neureiter, E. Fischer, M. Gramatzki,and E. G. Hahn. 2001. Pseudomembranous tracheobronchitis due toBacillus cereus. Clin. Infect. Dis. 33:e39–e41.

125. Tanabe, T., Y. Kodama, T. Nisaikawa, Y. Okamoto, and Y. Kawano. 2005.Critical illness polyneuropathy after Bacillus cereus sepsis in acute lympho-blastic leukemia. Int. Med. 48:1175–1177.

126. Tomomasa, T., K. Itoh, A. Matsui, T. Kobayashi, N. Suzuki, S. Matsuyama,and T. Kurome. 1993. An infant with ulcerative colitis complicated byendocarditis and cerebral infarction. J. Pediatr. Gasterenterol. Nutr. 17:323–325.

127. Tuazon, C. V., R. Hill, and J. N. Sheagren. 1974. Microbiologic study ofstreet heroin and injection paraphernalia. J. Infect. Dis. 129:327–329.

128. Tuazon, C. V., H. W. Murray, C. Levy, M. N. Solny, J. A. Curtin, and J. N.Sheagren. 1979. Serious infections from Bacillus species. JAMA 241:1137–1140.

129. Turnbull, P. C. B., K. Jorgensen, J. M. Kramer, R. J. Gilbert, and J. M.Perry. 1979. Severe clinical conditions associated with Bacillus cereus andthe apparent involvements of exotoxins. J. Clin. Pathol. 32:289–293.

130. Turnbull, P. C. B., and J. M. Kramer. 1985. Intestinal carriage of Bacilluscereus: fecal isolation studies in three population groups. J. Hyg. (Lond.)95:629–638.

131. Turnbull, P. C. B., J. Kramer, and J. Melling. 1990. Bacillus, p. 188–210. InW. W. C. Topley and G. S. Wilson (ed.), Topley and Wilson’s principles ofbacteriology, virology and immunity, 8th ed., vol. 2. Edward Arnold, Lon-don, United Kingdom.

132. Turnbull, P. C. B., N. M. Sirianni, C. L. LeBron, M. N. Samaan, F. N.Sutton, A. E. Reyes, and L. F. Peruski, Jr. 2004. MICs of selected antibioticsfor Bacillus anthracis, Bacillus cereus, Bacillus thuringiensis, and Bacillusmycoides from a range of clinical and environmental sources as determinedby Etest. J. Clin. Microbiol. 42:3626–3634.

133. Vahey, J. B., and H. W. Flynn. 1991. Results in the management of Bacillusendophthalmitis. Ophthalmic Surg. 22:681–686.

134. Van Der Zwet, W. C., G. A. Parlevliet, P. H. Savelkoul, J. Stoof, P. M.Kaiser, A. M. Van Furth, and C. M. Vanderbroucke-Grauls. 2000. Out-break of Bacillus cereus infections in a neonatal intensive care unit traced toballoons used in manual ventilation. J. Clin. Microbiol. 38:431–4136.

135. Vilain, S., Y. Luo, M. B. Hildreth, and V. S. Brozel. 2006. Analysis of the lifecycle of the soil saprophyte Bacillus cereus in liquid soil extract and in soil.Appl. Environ. Microbiol. 72:4970–4977.

136. Weber, D. J., S. M. Saviteer, W. A. Rutala, and C. A. Tomann. 1988. In vitrosusceptibility of Bacillus spp. to selected antimicrobial agents. Antimicrob.Agents Chemother. 32:642–645.

137. Weller, P., P. Nicholson, and M. Braslow. 1979. The spectrum of Bacillusbacteremia in heroin addicts. Arch. Intern. Med. 139:293–294.

138. Wong, M. T., and M. J. Dolan. 1992. Significant infections due to Bacillusspecies following abrasions associated with motor vehicle-related trauma.Clin. Infect. Dis. 15:855–857.

139. York, M. K. 1990. Bacillus species pseudobacteremia traced to contami-nated gloves used in collection of blood from patients with acquired im-munodeficiency syndrome. J. Clin. Microbiol. 28:2114–2116.

140. Yoshida, H., Y. Moriyama, T. Tatekawa, T. Tominaga, H. Teshima, H.Hiraoka, T. Masooka, and T. Yoshinaga. 1993. Two cases of acute myelog-enous leukemia with Bacillus cereus bacteremia resulting in fatal intracra-nial hemorrhage. Rinsho Ketsueki 34:1568–1572. (In Japanese.)

Continued next page



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

Edward J. Bottone, Ph.D., was born andraised in East Harlem in New York City. Hereceived his B.S. degree in biology from theCity College of New York, his master’s de-gree in public health and bacteriology fromWagner College, Staten Island, NY, and hisPh.D. from St. John’s University, Queens,NY. Dr. Bottone’s career in microbiologybegan when he was drafted into the U.S.Army in 1957 and was sent to Fort SamHouston in San Antonio, TX, where he wasselected to attend the Army Medical Service School course in MedicalTechnology. Upon completion of his training as a medical technolo-gist, Dr. Bottone was assigned to the 34th General Hospital in LaChapelle, France, where he was assigned to the Bacteriology Section ofthe laboratory. Upon completion of his Army tour in 1959, he joinedthe microbiology staff of the Mount Sinai Hospital in New York City,where, over a course of 16 years, he rose from the status of a JuniorTechnician to Director of the Microbiology Department en route toearning his bachelor’s, master’s, and doctoral degrees as a part-timeevening student. Dr. Bottone’s career has been highlighted by receiv-ing several of Mount Sinai’s most prestigious awards in addition toearning his American Board of Medical Microbiology (ABMM) cer-tification and diplomate status of the ABMM. He was honored forDistinguished Achievements in Clinical Microbiology by the AmericanSociety for Microbiology, New York City Branch (1995), and was therecipient of the bioMerieux-Vitek Sonnenwirth Memorial Award by theAmerican Society for Microbiology (1996) and the Professional Recog-nition Award by the American Academy of Microbiology (2002). Pres-ently, Dr. Bottone is Professor Emeritus of Medicine/Infectious Disease,Mount Sinai School of Medicine, and Professor of Medicine (InfectiousDiseases), New York Medical College, Valhalla, NY.



http://cmr.asm

.org/D

ownloaded from

http://cmr.asm.org/

bacillus cereus, a volatile human pathogenbacillus cereus is a gram-positive,...

Documents