anaerobic bacteria
DESCRIPTION
ÂTRANSCRIPT
![Page 1: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/1.jpg)
Anaerobic BacteriaAnaerobic Bacteria
![Page 2: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/2.jpg)
CategoryCategory
Spore-forming: Spore-forming: rod, Gram (+)--- Clostridiumrod, Gram (+)--- Clostridium Nonspore-forming: Nonspore-forming: see next slides see next slides
![Page 3: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/3.jpg)
Spore-Spore-forming:forming:
rod, Gram (+)--- Clostridiumrod, Gram (+)--- Clostridium
Nonspore-forming:Nonspore-forming:Rod, Gram (+)Rod, Gram (+) PropionibacteriumPropionibacterium 丙酸菌属
Bifidobacterium Bifidobacterium Lactobacillus Lactobacillus
EubacteriumEubacterium ActinomycesActinomyces
Rod, Gram (-)Rod, Gram (-) BacteroidesBacteroides Fusobacterium Fusobacterium 梭菌属 CampylobacterCampylobacter
Cocci, Gram (+)Cocci, Gram (+) Peptococcus Peptococcus Peptostreptococcus Peptostreptococcus
Cocci, Gram (-)Cocci, Gram (-) VeillonellaVeillonella
CategoryCategory
![Page 4: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/4.jpg)
Clostridium SpeciesClostridium Species
The clostridia are opportunistic The clostridia are opportunistic pathogens. Nonetheless, they are pathogens. Nonetheless, they are responsible for some of the deadliest responsible for some of the deadliest diseases including diseases including gas gangrene, gas gangrene, tetanus and botulismtetanus and botulism. Less life-. Less life-threatening diseases include threatening diseases include pseudomembranous colitispseudomembranous colitis (PC) and (PC) and food poisoning. food poisoning.
cause disease primarily through the cause disease primarily through the production of numerous exotoxins.production of numerous exotoxins.
perfringens, tetani, botulinum, difficileperfringens, tetani, botulinum, difficile
![Page 5: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/5.jpg)
Clostridium TetaniClostridium Tetani
Pathogenesis of tetanus caused by C tetani
![Page 6: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/6.jpg)
General introductionGeneral introduction
C tetaniC tetani is found worldwide. is found worldwide. Ubiquitous in Ubiquitous in soilsoil, it is occasionally , it is occasionally found in found in intestinal flora of humans intestinal flora of humans and animalsand animals
C.C.tetanitetani is the cause of is the cause of tetanustetanus,or ,or lockjawlockjaw. When spores are introduced . When spores are introduced into wounds by contaminated soil or into wounds by contaminated soil or foreign objects such as nails or glass foreign objects such as nails or glass splinterssplinters
![Page 7: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/7.jpg)
BIOCHEMICAL CHARACTERISTICSBIOCHEMICAL CHARACTERISTICS
MorphologyMorphology: long and slender; : long and slender; peritrichous flagella,no capsule, peritrichous flagella,no capsule, terminal located round terminal located round spore(drum-stick apperance), spore(drum-stick apperance), its diameter greater than its diameter greater than vegetative cellvegetative cell..
CultureCulture:obligate anaerobic; :obligate anaerobic; Gram(+); swarming occures on Gram(+); swarming occures on blood agar, faint hemolysis.blood agar, faint hemolysis.
Biochemical activities:Biochemical activities:does not does not ferment any carbohydrate and ferment any carbohydrate and proteins.proteins.
ResistanceResistance: tolerate boiling for : tolerate boiling for 60 min.alive several ten years in 60 min.alive several ten years in soil.soil.
ClassificationClassification and Antigenic and Antigenic Types: Types: C tetani C tetani is the only is the only species. There are no serotypesspecies. There are no serotypes
2-5 x 0.3-0.5um2-5 x 0.3-0.5um
![Page 8: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/8.jpg)
PathogenicityPathogenicity No invasiveness; toxemia No invasiveness; toxemia
(exogenous infection(exogenous infection )) produces two exotoxins: produces two exotoxins:
tetanolysin, and tetanolysin, and tetanospasmintetanospasmin(a kind of (a kind of neurotoxin, toxicity strong)neurotoxin, toxicity strong)
The actions of The actions of tetanospasmintetanospasmin are are complex and involve three complex and involve three components of the components of the nervous system: nervous system: central central motor controlmotor control, , autonomic autonomic functionfunction, and the , and the neuromuscular junctionneuromuscular junction..
retrograde transport retrograde transport to (CNS)to (CNS)
delitescencedelitescence :: a few a few days to several days to several weeksweeks
The two animal The two animal species most species most susceptible to this susceptible to this toxemia are horses toxemia are horses and and humanshumans..
![Page 9: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/9.jpg)
Clostridium tetaniClostridium tetani --TetanospasminTetanospasmin
disseminates systemically disseminates systemically binds to ganglioside receptors binds to ganglioside receptors
• inhibitory neurones in CNSinhibitory neurones in CNS glycine glycine
• neurotransmitterneurotransmitter stops nerve impulse to muscles stops nerve impulse to muscles spastic paralysisspastic paralysis 痉挛性麻痹 severe muscle contractions and severe muscle contractions and
spasms spasms can be fatalcan be fatal
![Page 10: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/10.jpg)
TetanospasminTetanospasmin
![Page 11: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/11.jpg)
Clinical ManifestationsClinical Manifestations The initial symptom is cramping and The initial symptom is cramping and
twitching of muscles around a wound. The twitching of muscles around a wound. The patient usually has patient usually has no feverno fever but sweats but sweats profusely and begins to experience pain, profusely and begins to experience pain, especially in the area of the wound and especially in the area of the wound and around the neck and jaw muscles around the neck and jaw muscles (trismus)(trismus)..
Portions of the body may become extremely Portions of the body may become extremely rigid, and rigid, and opisthotonosopisthotonos 角弓反张 (a spasm (a spasm in which the head and heels are bent in which the head and heels are bent backward and the body bowed forward) is backward and the body bowed forward) is common.common.
Complications include fractures, bowel Complications include fractures, bowel impaction, intramuscular hematoma, muscle impaction, intramuscular hematoma, muscle ruptures, and pulmonary, renal, and cardiac ruptures, and pulmonary, renal, and cardiac problemsproblems
![Page 12: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/12.jpg)
Clinical ManifestationsClinical ManifestationsDISEASEDISEASE CLINCAL MANIFESTATIONSACLINCAL MANIFESTATIONSAGeneralizedGeneralized Involvement of bulbar and paraspinal Involvement of bulbar and paraspinal
muscles(trismus or lockjaw, risus sardonicus, muscles(trismus or lockjaw, risus sardonicus, difficulty swallowing, irritability, difficulty swallowing, irritability, opisthotonos);involvement of autonomic opisthotonos);involvement of autonomic nervous system(sweating, hyper thermia, nervous system(sweating, hyper thermia, cardiac arrhythmias, fluctuations in blood cardiac arrhythmias, fluctuations in blood pressure)pressure)
CephalicCephalic Primary infection in head,particularly Primary infection in head,particularly ear;isolated or combined involvement of cranial ear;isolated or combined involvement of cranial nerves, particularly seventh cranial nerve; very nerves, particularly seventh cranial nerve; very poor prognosispoor prognosis
LocalizedLocalized Involvement of muscles in area of primary Involvement of muscles in area of primary injury; infection may precede generalized injury; infection may precede generalized disease; favorable prognosisdisease; favorable prognosis
NeonatalNeonatal Generalized disease in neonates; infection Generalized disease in neonates; infection typically originates from umbilicaltypically originates from umbilical 脐带stump;very poor prognosis in infants whose stump;very poor prognosis in infants whose mothers are nonimmunemothers are nonimmune
![Page 13: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/13.jpg)
![Page 14: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/14.jpg)
EpidemiologyEpidemiology 1 1 million cases of tetanus occur annually in the million cases of tetanus occur annually in the
world,with a mortality rate ranging from20% to world,with a mortality rate ranging from20% to 50%. But rare in most developed countries. 50%. But rare in most developed countries.
In some In some developing countriesdeveloping countries, tetanus is still , tetanus is still one of the ten leading causes of death, and one of the ten leading causes of death, and neonatal tetanus accounts for approximately neonatal tetanus accounts for approximately one-half of the cases worldwide.one-half of the cases worldwide.
In less developed countries, approximate In less developed countries, approximate mortality rates remain 85% for neonatal mortality rates remain 85% for neonatal tetanus and 50% for nonneonatal tetanus. tetanus and 50% for nonneonatal tetanus.
In the United States, intravenous drug abusers In the United States, intravenous drug abusers have become another population with an have become another population with an increasing incidence of clinical tetanusincreasing incidence of clinical tetanus
In untreated tetanus, the fatality rate is In untreated tetanus, the fatality rate is 90%90% for the newborn and for the newborn and 40%40% for adults. for adults.
![Page 15: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/15.jpg)
ImmunityImmunity
Humoral immunityHumoral immunity(antitoxin)(antitoxin) There is little, if any, inate immunity There is little, if any, inate immunity
and the disease does not produce and the disease does not produce immunity in the patient. immunity in the patient.
Active immunity follows vaccination Active immunity follows vaccination with tetanus with tetanus toxoidtoxoid
![Page 16: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/16.jpg)
DiagnosisDiagnosis Diagnosis is primarily by Diagnosis is primarily by the clinical the clinical
symptoms (above).symptoms (above). The wound may not The wound may not be obvious. be obvious.
C tetani can be recovered from the C tetani can be recovered from the wound in only about one-third of the wound in only about one-third of the cases.cases.
It is important for the clinician to be It is important for the clinician to be aware that toxigenic strains of C tetani aware that toxigenic strains of C tetani can grow actively in the wound of an can grow actively in the wound of an immunized person.immunized person.
Numerous syndromes, including Numerous syndromes, including rabies rabies and meningitis,and meningitis, have symptoms similar have symptoms similar to those of tetanus and must be to those of tetanus and must be considered in the differential diagnosis.considered in the differential diagnosis.
![Page 17: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/17.jpg)
• infantinfant• DPT (diptheria, pertussis, tetanus)DPT (diptheria, pertussis, tetanus)• tetanus toxoid tetanus toxoid
– antigenicantigenic– no exotoxic activityno exotoxic activity
VaccinationVaccination
![Page 18: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/18.jpg)
ControlControl The offending organism must be The offending organism must be
removed by local removed by local debridemendebridemen 清创术 toxoid toxoid TATTAT; Metronidazole (For more ; Metronidazole (For more
serious wounds)serious wounds) AIDSAIDS patients may not respond patients may not respond
to prophylactic injections of to prophylactic injections of tetanus toxoidtetanus toxoid
![Page 19: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/19.jpg)
C. perfringensC. perfringens• soil, fecal contaminationsoil, fecal contamination• gas gangrenegas gangrene
– swelling of tissues swelling of tissues – gas releasegas release
* fermentation productsfermentation products• wound contaminationwound contamination
![Page 20: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/20.jpg)
ToxinsToxinstoxintoxin Biological Biological
FeatureFeatureTypes of ToxinsTypes of Toxins
AA BB CC DD EE lecithinaselecithinase; increase the ; increase the
vascular permeability; vascular permeability; hemolytic; produces hemolytic; produces necrotizing activitynecrotizing activity
++ ++ ++ ++ ++ Necrotizing activity, Necrotizing activity,
induces hypertension induces hypertension by causing release of by causing release of catecholamines.catecholamines.
-- ++ ++ -- --
increase the increase the permeability of permeability of gastrointestinal wallgastrointestinal wall
-- -- -- ++ -- Necrotizing activity; Necrotizing activity;
increase the vascular increase the vascular permeability permeability
-- -- -- -- ++
![Page 21: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/21.jpg)
ToxinsToxins Many of these toxins have lethal, Many of these toxins have lethal,
necrotizing, and hemolytic properties;necrotizing, and hemolytic properties; The alpha toxin produced by all types of The alpha toxin produced by all types of C. C.
perfringens,perfringens, is a lecithinase that lyses is a lecithinase that lyses erythrocytes, platelets, leukocytes, and erythrocytes, platelets, leukocytes, and endothelial cells. And its lethal action is endothelial cells. And its lethal action is proportionate to the rate at which it splits proportionate to the rate at which it splits lecithin to phosphorylcholine and lecithin to phosphorylcholine and diglyceride.diglyceride.
The theta toxin has similar hemolytic and The theta toxin has similar hemolytic and necrotizing effects.necrotizing effects.
DNAase, hyaluronidase, a collagenase are DNAase, hyaluronidase, a collagenase are also producedalso produced
![Page 22: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/22.jpg)
EnterotoxinEnterotoxin Many strains of type A produce Many strains of type A produce
enterotoxin, which is a heat-labile protein enterotoxin, which is a heat-labile protein and destroyed immediately at 100 ℃.and destroyed immediately at 100 ℃.
Trypsin treatment enhances the toxin Trypsin treatment enhances the toxin activity threefold.activity threefold.
The toxin is produced primarily by type A The toxin is produced primarily by type A strains but also by a few type C and D strains but also by a few type C and D strains.strains.
It disrupts ion transport in the It disrupts ion transport in the ileum(primarily) and jejunum by inserting ileum(primarily) and jejunum by inserting into the cell membrane and altering into the cell membrane and altering membrane permeability.membrane permeability.
As superantigen. As superantigen.
![Page 23: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/23.jpg)
![Page 24: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/24.jpg)
•Tissue degrading enzymes Tissue degrading enzymes – lecithinase [lecithinase [ toxin] toxin]– proteolytic enzymesproteolytic enzymes– saccharolytic enzymessaccharolytic enzymes
• Destruction of blood vessels Destruction of blood vessels • Tissue necrosisTissue necrosis• Anaerobic environment created Anaerobic environment created • Organism spreadsOrganism spreads
PathogenesisPathogenesis
![Page 25: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/25.jpg)
Without treatment death Without treatment death occurs within 2 daysoccurs within 2 days effective antibiotic therapyeffective antibiotic therapy debridement debridement anti-toxinanti-toxin amputation & death is rareamputation & death is rare
![Page 26: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/26.jpg)
Gas gangreneGas gangrene Gas gangreneGas gangrene is a life-threatening disease with is a life-threatening disease with
a poor prognosis and often fatal outcome. a poor prognosis and often fatal outcome. Initial trauma to host tissue damages muscle and Initial trauma to host tissue damages muscle and
impairs blood supply----lack of oxygenation impairs blood supply----lack of oxygenation Initial symptomsInitial symptoms : : fever fever and pain in the infected and pain in the infected
tissue.; more local tissue necrosis and systemic tissue.; more local tissue necrosis and systemic toxemia. Infected muscle is discolored (purple toxemia. Infected muscle is discolored (purple mottling) and edematous and produces a mottling) and edematous and produces a foulfoul--smelling exudate; gas smelling exudate; gas bubblesbubbles form from the form from the products of anaerobic fermentation. products of anaerobic fermentation.
![Page 27: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/27.jpg)
Gas gangreneGas gangrene As capillary permeability increases, As capillary permeability increases,
the accumulation of fluid increases, the accumulation of fluid increases, and venous return eventually is and venous return eventually is curtailed. curtailed.
As more tissue becomes involved, the As more tissue becomes involved, the clostridia multiply within the clostridia multiply within the increasing area of dead tissue, increasing area of dead tissue, releasing more toxins into the local releasing more toxins into the local tissue and the systemic circulation. tissue and the systemic circulation.
![Page 28: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/28.jpg)
Food poisoningFood poisoning
Enterotoxin producing strainsEnterotoxin producing strains.. These bacteria are found in These bacteria are found in
mammalian mammalian faeces and soilfaeces and soil. . Small numbers of the bacteria may Small numbers of the bacteria may
also be found in foods and they may also be found in foods and they may propagate rapidly to dangerous propagate rapidly to dangerous concentrations if the food is concentrations if the food is improperly stored and handled. improperly stored and handled.
![Page 29: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/29.jpg)
Food poisoningFood poisoning
more than 10more than 1088 vegetative cells are vegetative cells are ingested and sporulate in the gut, the ingested and sporulate in the gut, the toxins can act rapidly in the body, toxins can act rapidly in the body, causing severe diarrhea in 6-18 hours, causing severe diarrhea in 6-18 hours, dysentery, gangrene, muscle infections dysentery, gangrene, muscle infections
The action of The action of C. perfringensC. perfringens enterotoxin enterotoxin involves marked hypersecretion in the involves marked hypersecretion in the jejunum and ileum, with loss of fluids jejunum and ileum, with loss of fluids and electrolytes in diarrhea.and electrolytes in diarrhea.
![Page 30: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/30.jpg)
Cellulitis, FasciitisCellulitis, Fasciitis
Cellulitis, FasciitisCellulitis, Fasciitis Fasciitis : a rapidly progressive, Fasciitis : a rapidly progressive,
destructive process in which the destructive process in which the organisms spread through fascial plan es.organisms spread through fascial plan es.
Fasciitis causes suppuration and the Fasciitis causes suppuration and the formation of gasformation of gas
Absense of muscle involvementAbsense of muscle involvement rapidityrapidity
![Page 31: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/31.jpg)
Necrotizing EnteritisNecrotizing Enteritis Rare, acute necrotizing process in the Rare, acute necrotizing process in the
jejunumjejunum Abdominal pain, bloody diarrhea, shock, and Abdominal pain, bloody diarrhea, shock, and
peritonitisperitonitis Mortality: 50%Mortality: 50% Beta-toxin-producing Beta-toxin-producing C. perfringensC. perfringens type C type C SepticemiaSepticemia
![Page 32: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/32.jpg)
Who is at risk?Who is at risk? Surgical patientsSurgical patients; patient after ; patient after
trauma with soil contamination.trauma with soil contamination. People who ingest contaminated People who ingest contaminated
meat productsmeat products (without proper (without proper refrigeration or reheating to refrigeration or reheating to inactivate endotoxin)inactivate endotoxin)
![Page 33: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/33.jpg)
EpidemiologyEpidemiology C. perfringensC. perfringens type A: type A: the intestinal the intestinal
tract of humans and animals, soil and tract of humans and animals, soil and water contaminated with feces. forms water contaminated with feces. forms spores under adverse environmental spores under adverse environmental conditions and can survive for conditions and can survive for prolonged periods.prolonged periods.
Type B to E strainsType B to E strains colonize the colonize the intestinal tract of animals and intestinal tract of animals and occasionally humans.occasionally humans.
![Page 34: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/34.jpg)
EpidemiologyEpidemiology Type AType A: gas gangrene, soft tissue : gas gangrene, soft tissue
infections and food poisoninginfections and food poisoning Type CType C: enteritis; necroticans: enteritis; necroticans
![Page 35: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/35.jpg)
• lecithinase productionlecithinase production
Laboratory identification
Double Hemolysis CirclesDouble Hemolysis Circles
![Page 36: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/36.jpg)
C. botulinumC. botulinum
![Page 37: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/37.jpg)
Biological FeaturesBiological Features
AnaerobicAnaerobic Gram-positiveGram-positive rod-shapedrod-shaped sporeformersporeformer produces a protein neurotoxic.produces a protein neurotoxic. soil, sediments of lakes, ponds, soil, sediments of lakes, ponds,
decaying vegetation.decaying vegetation. intestinal tracts of birds, mammals intestinal tracts of birds, mammals
and fish.and fish.
![Page 38: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/38.jpg)
---A, B, C1, D, E, F, and G.---type A. 62% ---Not all produce toxin.---C and D not ---G plasmid encoded.
DivisionDivision
![Page 39: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/39.jpg)
---spores heat resistant. canning. anaerobic environment ---Botulism eating uncooked foods spores---GI, duodenum, blood stream, neuromuscular synapses.
TransmissionTransmission
![Page 40: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/40.jpg)
---bacterial protease ---light chain,A,50 kDa; heavy chain,100kDa.---disulfide bond. ---A potent toxin
Virulence factorsVirulence factors
![Page 41: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/41.jpg)
Botulinum toxinBotulinum toxin
binds peripheral nerve receptorsbinds peripheral nerve receptors• acetylcholine neurotransmitteracetylcholine neurotransmitter
inhibits nerve impulses inhibits nerve impulses flaccid paralysisflaccid paralysis death death
• respiratory respiratory • cardiac failurecardiac failure
![Page 42: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/42.jpg)
Botulinum toxinBotulinum toxin BioterrorismBioterrorism
• not an infectionnot an infection• resembles a chemical attack resembles a chemical attack • 10 ng can kill a normal adult10 ng can kill a normal adult
![Page 43: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/43.jpg)
---4: foodborne, infant, wound, undetermined. ---Certain foods; wound not.---Foodborne botulism, consumption.---Infant botulism, 1976, under 12m. ---ingestion, colonize and produce toxin in the intestinal tract of infants. honey. ---increased.---internationally recognized.
EpidemiologyEpidemiology
![Page 44: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/44.jpg)
---18-36 hours: ---weakness, dizziness,dryness of the mouth. ---Nausea,vomiting. ---Neurologic features: blurred vision, inability to swallow, difficulty in speech, descending weakness of skeletal muscles, respiratory paralysis.
Clinical syndromesClinical syndromes
![Page 45: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/45.jpg)
BotulismBotulism(( 肉毒中毒肉毒中毒 ))
food poisoningfood poisoning • rarerare• fatalfatal
germination of spore germination of spore inadequately sterilized canned inadequately sterilized canned
food food • homehome
not an infectionnot an infection
![Page 46: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/46.jpg)
Infection with Infection with C. botulinumC. botulinum
Neonatal botulismNeonatal botulism• uncommonuncommon• the predominant form of the predominant form of
botulismbotulism• colonization occurscolonization occurs
no normal flora to competeno normal flora to compete unlike adultunlike adult
![Page 47: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/47.jpg)
WoundsWounds
•extremely rareextremely rare•an infectionan infection
![Page 48: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/48.jpg)
ImmunityImmunity ------specifically neutralized, specifically neutralized, antitoxinantitoxin. . ---toxoided, make good antigens.---toxoided, make good antigens.---does not develop, amount toxic. ---does not develop, amount toxic. ---Repeated occurrence. ---Repeated occurrence. ---Once bound, unaffected by antitoxin.---Once bound, unaffected by antitoxin.---circulating toxin ,neutralized , injection ---circulating toxin ,neutralized , injection
of antitoxin.of antitoxin.---treated immediately with antiserum. ---treated immediately with antiserum. ------multivalent multivalent
toxoid,unjustified,infrequency. toxoid,unjustified,infrequency. experimental vaccine. experimental vaccine.
![Page 49: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/49.jpg)
DiagnosisDiagnosis
---by clinical symptoms alone---differentiation difficult. --- most direct and effective: serum or feces. ---most sensitive and widely used: mouse neutralization test. 48h. Culturing of specimens 5-7d.
![Page 50: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/50.jpg)
TreatmentTreatment
Individuals known to have ingested food Individuals known to have ingested food with botulism should be treated with botulism should be treated immediately with antiserum. immediately with antiserum.
antibiotic therapy (if infectionantibiotic therapy (if infection))• Vaccination will not protect hosts Vaccination will not protect hosts
from botulism, however passive from botulism, however passive immunisation with antibody is the immunisation with antibody is the treatment of choice for cases of treatment of choice for cases of botulism. botulism.
![Page 51: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/51.jpg)
Prevention Prevention
------proper food handling and preparation. proper food handling and preparation. --- spores survive boiling (100 degrees at --- spores survive boiling (100 degrees at
1 atm) 1h. 1 atm) 1h. ---toxin heat-labile, boiling or intense ---toxin heat-labile, boiling or intense
heating, inactivate the toxin. heating, inactivate the toxin. ------bulge, gas, spoiledbulge, gas, spoiled..
![Page 52: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/52.jpg)
C. difficileC. difficile
• After antibiotic use After antibiotic use • Intestinal normal flora --greatly decreasedIntestinal normal flora --greatly decreased• Colonization occurs Colonization occurs • Enterotoxin secreted Enterotoxin secreted • Pseudomembanous colitis Pseudomembanous colitis
![Page 53: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/53.jpg)
Pseudomembranous ColitisPseudomembranous Colitis
Pseudomembranous colitis (PC) results Pseudomembranous colitis (PC) results predominantly as a consequence of the predominantly as a consequence of the elimination of normal intestinal flora elimination of normal intestinal flora through antibiotic therapy. through antibiotic therapy.
Symptoms include Symptoms include abdominal abdominal pain with pain with a a watery diarrheawatery diarrhea and leukocytosis. and leukocytosis. ""PseudomembranesPseudomembranes" consisting of " consisting of fibrin, mucus and leukocytes can be fibrin, mucus and leukocytes can be observed by colonoscopy. observed by colonoscopy.
Untreated pseudomembranous colitis Untreated pseudomembranous colitis can be fatal in about can be fatal in about 27-44%.27-44%.
![Page 54: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/54.jpg)
TherapyTherapy
Discontinuation of initial antibiotic Discontinuation of initial antibiotic (e.g. ampicillin)(e.g. ampicillin)
Specific antibiotic therapy (e.g. Specific antibiotic therapy (e.g. vancomycin)vancomycin)
![Page 55: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/55.jpg)
• no oxidative phosphorylationno oxidative phosphorylation• fermentationfermentation• killed by oxygenkilled by oxygen• lack certain enzymeslack certain enzymes
– superoxide dismutase superoxide dismutase * OO22
--+2H+2H++ H H22OO2 2
– catalase catalase * HH22OO2 2 H H220 + O0 + O22
– peroxidase peroxidase * HH22OO22 H H2200 /NAD to NADH/NAD to NADH
Obligate Obligate (strict)(strict) anaerobes anaerobes
![Page 56: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/56.jpg)
Strict anaerobe infectious Strict anaerobe infectious diseasedisease
Sites throughout body Sites throughout body Muscle, cutaneous/sub-cutaneous Muscle, cutaneous/sub-cutaneous
necrosisnecrosis AbscessesAbscesses
![Page 57: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/57.jpg)
![Page 58: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/58.jpg)
Bacterial Flora of the BodyBacterial Flora of the BodySiteSite Total BacteriaTotal Bacteria RatioRatio
(per/ml or gm)(per/ml or gm) Anaerobes:Aerobes Anaerobes:Aerobes
Upper AirwayUpper AirwayNasal WashingsNasal Washings 101033-10-1044 3-5:13-5:1SalivaSaliva 101088-10-1099 1:11:1Tooth SurfaceTooth Surface 10101010-10-101111 1:11:1Gingival CreviceGingival Crevice 10101111-10-101212 1000:1 1000:1
Gastrointestinal TractGastrointestinal Tract
Stomach Stomach 101022-10-1055 1:11:1Small BowelSmall Bowel 101022-10-1044 1:11:1IleumIleum 101044-10-1077 1:11:1ColonColon 10101111-10-101212 1000:11000:1
Female Genital TractFemale Genital Tract
EndocervixEndocervix 101088-10-1099 3-5:13-5:1VaginaVagina 101088-10-1099 3-5:13-5:1
![Page 59: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/59.jpg)
Problems in identification of Problems in identification of anaerobic infectionsanaerobic infections
• air in sample (sampling, transportation)air in sample (sampling, transportation)– no growthno growth
• identification takes several days or longeridentification takes several days or longer– limiting usefulnesslimiting usefulness
• often derived from normal flora often derived from normal flora – sample contamination can confuse sample contamination can confuse
![Page 60: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/60.jpg)
Virulence FactorsVirulence Factors
1.1. Anti-phagocytic capsuleAnti-phagocytic capsule• Also promote abscess formationAlso promote abscess formation
2.2. Tissue destructive enzymesTissue destructive enzymes• B. fragilisB. fragilis produces variety of enzymes produces variety of enzymes
(lipases, proteases, collagenases) that (lipases, proteases, collagenases) that destroy tissue destroy tissue Abscess Formation Abscess Formation
3.3. Beta-lactamase productionBeta-lactamase production• B. fragilis B. fragilis – protect themselves and other – protect themselves and other
species in mixed infectionsspecies in mixed infections4.4. Superoxide dismutase productionSuperoxide dismutase production
• Protects bacteria from toxic OProtects bacteria from toxic O22 radicals as radicals as they move out of usual nichethey move out of usual niche
![Page 61: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/61.jpg)
Characteristics of Anaerobic InfectionsCharacteristics of Anaerobic Infections
1.1. Most pathogenic anaerobes are Most pathogenic anaerobes are usually commensalsusually commensals• Originate from our Originate from our own floraown flora
2.2. Predisposing ConditionsPredisposing Conditions• Breeches in the mucocutaneous barrier Breeches in the mucocutaneous barrier
displace normal floradisplace normal flora• Compromised vascular supplyCompromised vascular supply• Trauma with tissue destructionTrauma with tissue destruction• Antecedent infectionAntecedent infection
![Page 62: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/62.jpg)
Characteristics of Anaerobic Characteristics of Anaerobic InfectionsInfections
3. 3. Complex FloraComplex Flora Multiple speciesMultiple species
• Abdominal Infection Abdominal Infection Avg Avg of 5 speciesof 5 species
3 anaerobic3 anaerobic 2 aerobic2 aerobic
• Less complex then nl floraLess complex then nl flora• Fecal flora 400 different Fecal flora 400 different
species species Those predominant in stool Those predominant in stool
are not infecting species are not infecting species • Veillonella, Veillonella,
Bifidobacterium Bifidobacterium rarely rarely pathogenicpathogenic
• Species uniquely suited to Species uniquely suited to cause infection cause infection predominatepredominate
4.4. Synergistic Mixture Synergistic Mixture of Aerobesof Aerobes & & AnaerobesAnaerobes
E. coliE. coli Consume O Consume O22
• Allow growth Allow growth of of anaerobesanaerobes
Anaerobes Anaerobes promote promote growth of other growth of other bacteria by being bacteria by being antiphagocytic and antiphagocytic and producing B-producing B-lactamaseslactamases
![Page 63: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/63.jpg)
Clues to Anaerobic InfectionClues to Anaerobic Infection1.1. Infections in continuity to mucosal Infections in continuity to mucosal
surfacessurfaces2.2. Infections with tissue necrosis and Infections with tissue necrosis and
abscess formation abscess formation 3.3. Putrid odorPutrid odor4.4. Gas in tissuesGas in tissues5.5. Polymicrobial floraPolymicrobial flora6.6. Failure to grow in the lab Failure to grow in the lab
BIOCHEMICAL KITS BIOCHEMICAL KITS • e.g. API SYSTEMe.g. API SYSTEM
GAS CHROMATOGRAPHYGAS CHROMATOGRAPHY• volatile fermentation productsvolatile fermentation products
![Page 64: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/64.jpg)
Bacteroides fragilisBacteroides fragilis• Major disease causing strict anaerobic Major disease causing strict anaerobic after abdominal surgeryafter abdominal surgery non-spore-formernon-spore-former
• Prominent capsuleProminent capsule– anti-phagocyticanti-phagocytic– abscess formationabscess formation
• Endotoxin Endotoxin – low toxicitylow toxicity– structure different than other structure different than other lipolysaccharide lipolysaccharide
![Page 65: Anaerobic Bacteria](https://reader036.vdocuments.net/reader036/viewer/2022062305/568bf3a81a28ab89339b1ee8/html5/thumbnails/65.jpg)
• EnterobacteriaceaeEnterobacteriaceae (facultative anaerobes) (facultative anaerobes) – commonly cause diseasecommonly cause disease– low numbers gut floralow numbers gut flora
• Strict anaerobesStrict anaerobes – much less commonly cause disease much less commonly cause disease – high numbers gut florahigh numbers gut flora .