listeriosis - vet.chula.ac.th · listeriosis outbreaks!in 1981, 41 cases of listeriosis including...

ListeriosisListeriosisListeriosisListeriosisListeriosisListeriosisListeriosisListeriosis

Listeria monocytogenesListeria monocytogenes

!Gram positive

!Motile by flagella

!Non spore forming bacteria

!Facultative anaerobic bacteria

!Psychrotroph: grow at 0 °C to 5 °C

!Causes foodborne infections: High risk group

! Infants

!Pregnant women

! Immunocompromised persons

! Estimated 2,000 cases of listeriosis occurs annually


!1-10% of humans may be carriers ofL. monocytogenes.

! I t has been found!at least 37 mammalian species, both domestic and feral

!at least 17 species of birds

!possibly some species of fish and shellfish.

! I t can be isolated from soil, silage, and otherenvironmental sources.

!L. monocytogenes is quite hardy and resists thedeleterious effects of freezing, drying, and heat

!Most L. monocytogenes are pathogenic to somedegree


!Unique characteristic

!Psychrophilic bacteria

!Salt tolerant: NaCl 5-10%

!Acid tolerant: pH 4-5

!Infective dose: Unknown

!Vary with strain and susceptibility of host

!Susceptible person < 1,000 organism

!Normal may need 108-109

ListeriosisListeriosis

!Foodborne infection! Incubation period:

!Gastrointestinal form: > 12 hrs!Serious form of listeriosis: Unknown (range from 2 day-3

weeks)

!Duration of illness: 7 days!Clinical signs

!3 major clinical manifestation!Septicemia

!Meningitis (Meningo-encepphalitis)!Abortion

!Usually preceded by influenza-like symptomsincluding persistent fever

!Gastrointestinal symptoms!nausea, vomiting, and diarrhea


! Susceptible persons, fewer than 1,000 total organisms may

cause disease

! L. monocytogenes

! invades the gastrointestinal epithelium.

! enters the host's monocyte, macrophages, or polymorphonuclear

leukocytes

! Septicemia

! I ts presence intracellularly in phagocytic cells also permits

access to the brain and probably transplacental migration to the

fetus in pregnant women

! The pathogenesis of L. monocytogenes centers on its ability to

survive and multiply in phagocytic host cells.


!Mortality rate 25-30%!Listeric meningitis, the overall mortality may be as high as

70%;

!Septicemia 50%,

!Perinatal/neonatal infections greater than 80%.

! In infections during pregnancy, the mother usually survives

!Target Populations: The main target populations forlisteriosis are:!pregnant women/fetus - perinatal and neonatal infections;

!persons immunocompromised by corticosteroids, anticancerdrugs, graft suppression therapy, AIDS, cancer patients -leukemic patients

!Less frequently reported - diabetic, cirrhotic, and asthmaticpatients

!The elderly

Listeriosis Listeriosis outbreakoutbreak

!L. monocytogenes has been associated with!Raw milk

!Pasteurized fluid milk

!Cheeses (particularly soft-ripened varieties)

!Ice cream

!Fermented raw-meat sausages

!Raw and cooked poultry, raw meats (all types),and raw and smoked fish

!I ts ability to grow at temperatures as low as 3 °Cpermits multiplication in refrigerated foods

ListeriosisListeriosis outbreaks outbreaks

! In 1981, 41 cases of listeriosis including 18 deaths!83% of the cases were perinatal (near the time of birth)

!Outbreak traced to L. monocytogenes on coleslaw

!Cabbage grown in field fertilized with manure from Listeria-infected sheep

!49 cases of listeriosis including 14 deaths!14% perinatal

!Other immunocompromised adults

!Pasteurized milk from Listeria-infected dairy cows

ListeriosisListeriosis outbreaks outbreaks

! In 1985, 142 cases of listeriosis including 46 deaths

!85% of the cases were perinatal

!Outbreak traced to L. monocytogenes on soft, Mexican-style

cheese

!Cheese were manufactured with contaminated milk

!32 cases of listeriosis including 11 deaths

!The cause was never identified

ListeriosisListeriosis case study case study

!Multistate outbreak of Listeriosis

!Since early August 1998, 40 illnesses caused by a singlestrain of Listeria monocytogenes 4b (LM) have beenidentified in 10 states

!Six adults have died

!Two pregnant women have had spontaneous abortions

!All LM isolates from these cases are serotype 4b and sharean unusual pattern when subtyped either by pulsed-field gelelectrophoresis or by ribotyping methods

! Historically, this pattern is rare among LM isolates fromhumans


!Outbreak investigation

!Conducted a multistate case-control study

!Comparing 4-week food histories of 20 patients infected withthe outbreak strain with those of 20 control patients infectedwith other LM strains

!Sixteen (89%) of 18 cases but only six (32%) of 19 controlsconsumed cooked hot dogs during the month before illnessonset

!Odds ratio= 17.3; 95% confidence interval= 2.4-160.0; P<than 0.01

!On December 19, the outbreak strain of LM was isolatedfrom an open package of hot dogs

!These hot dogs had been eaten by a patient 4 weeks beforeonset of listeriosis caused by the outbreak strain


!Recall products

!The manufacturer, Bil Mar Foods, voluntarily recalled specificproduction lots of hot dogs and other meat products thatmight be contaminated

!The affected products bear the establishment numbers ESTP261 or EST 6911 and include the Ball Park, Bil Mar, BryanBunsize and Bryan 3-lb Club Pack, Grillmaster, Hygrade, Mr.Turkey, Sara Lee Deli Meat, and Sara Lee Home Roastbrands

!The establishment number appears on the outer edge of allpackages

!What is the source of contamination?


!L. monocytogenes prevention and control

!Education!Consumer

!High risk group

!Food of concerns

!People at risk should avoid high risk food

!Control of food!Washing, Chlorinate water

!Adding lactic acid during chess production

!Good sampling plan!Class 10-15

Isolation ofIsolation of Listeria monocytogenes Listeria monocytogenes

!Enrichment

!Selective plating

!Biochemical confirmation

!Enrichment

!Cold enrichment media and incubate at 4 °C for several days

!TSB+ acriflavin+ nalidixic acid+ cycloheximide

!Small number of L. monocytogenes

!Allow L. monocytogenes to grow and inhibit competition


!Selective plating

!MMA (Modified MacBride Agar)

!LPM (Lithium chloride Phenylethanol Moxalactam agar)

!PALCAM!Polymicin B

!Acriflavin

!LiCl

!Esculin (positive)

!Manitol (negative)

!Oxford agar!Antibiotic agar: more selective


!Biochemical confirmation

!TSB: motility

!Beta hemolysis

!Ferment rhamnose, xylose, and glucose

!Catalase positive

!Oxidase negative

!Specific DNA probes allow a simpler and fasterconfirmation of suspected isolates

VibriosisVibriosisVibriosisVibriosisVibriosisVibriosisVibriosisVibriosis

Vibrio Vibrio sppspp..

!Gram negative, straight, curved, comma shape

!Non spore forming bacteria

!Mesophilic bacteria

!Vibrio parahaemolyticus

!Halophilic group

!Vibrio cholerae! Non-halophilic group

!V. cholerae serogroup O1

!V. cholerae serogroup Non-O1

!Vibrio vulnificus

Vibrio parahaemolyticusVibrio parahaemolyticus

!Vibrio parahaemolyticus is frequently isolated fromthe marine animals and environment

!Both pathogenic and non-pathogenic forms of theorganism can be isolated from marine environmentsand from fish and shellfish dwelling in theseenvironments.

!V. parahaemolyticus-associated gastroenteritis

!Foodborne infection associated with the consumptionof seafood

Vibrio parahemolyticusVibrio parahemolyticus

!Unique characteristic

!Require NaCl to grow (Halophilic bacterium)

!V. Cholerae (Non-halophilic)

!Temperature 6 °C to 10 °C

!V. parahaemolyticus grow at 6 °C (Use to differentiate Vibrio

Spp.)

!Ferment sugar

!V. cholerae ferment sugar

! Infective dose: high infective dose (>105 CFU/g)

VibriosisVibriosis

!Foodborne infection (V. parahaemolyticus-associatedgastroenteritis )

! Incubation period: 12-18 hrs!Duration of illness: 2-5 days!Clinical signs

!Fever, chills!Nausea, Vomit!Abdominal cramps!Profuse diarrhea often leading to severe dehydration! Usually self-limiting

!The illness is usually mild or moderate, althoughsome cases may require hospitalization

!Disease is caused when the organism attaches itselfto small intestine and excretes an as yet unidentifiedtoxin

Vibrio parahaemolyticusVibrio parahaemolyticus outbreaks outbreaks

!Most common: Seafood (Fish, shellfish)

! Infections with this organism have been associated

with the consumption of raw, improperly cooked, or

cooked, recontaminated fish and shellfish

!A correlation exists between the probability of

infection and warmer months of the year

!All year in warmer climates

! Improper refrigeration of seafood contaminated with

this organism will allow its proliferation, which

increases the possibility of infection

Vibrio parahaemolyticusVibrio parahaemolyticus outbreak outbreak

!Before 1997, foodborne outbreaks caused byV. parahaemolyticus had been infrequently reportedin the United States

!During 1997-1998, multistate outbreaks ofV. parahemolyticus were associated withconsumption of raw or undercooked oystersharvested from the Pacific Northwest and Texas

! In Japan, high prevalence of V. parahemolyticusgastroenteritis: consumption of raw seafood

Vibrio parahaemolyticusVibrio parahaemolyticus case study case study

V. parahaemolyticus foodborne infection

!July-September 1998, an outbreak of Vibrio

parahaemolyticus infections associated with

consumption of oysters and clams

! Profuse diarrhea were reported among residents of Connecticut,

New Jersey, and New York.

! 23 culture-confirmed cases of V. parahaemolyticus

! Dates of illness onset ranged from July 21 through September 17

Vibrio parahemolyticusVibrio parahemolyticus case study case study

!Outbreak investigation!22 of 23 ill persons had eaten or handled oysters, clams, or

crustaceans

!16 ate raw oysters or clams, two ate steamed crabs, one atecrab cakes, one ate boiled crabs and lobsters, one atelobster roll, and one handled live crabs

!The median onset of illness following consumption ofshellfish was 19 hours (range: 12-52 hours)

! Clinical histories were available for 19 of the 23 ill persons;17 (89%) had gastroenteritis and two (11%) hadbloodstream infections with lower extremity edema

! Among patients with gastroenteritis, reported clinicalsymptoms included diarrhea (100%), abdominal cramps(94%), nausea (94%), vomiting (82%), fever (47%), bloodystools (29%), headache (24%), and myalgia (24%)

! Median duration of gastrointestinal illness was 5 days


!Traceback investigation

! Identified the site of harvest for oysters or clams eaten by11 of the 16 patients

!Oysters or clams eaten by eight patients were harvestedfrom Oyster Bay, off New York's Long Island Sound

!During the outbreak period, mean surface watertemperature measurements from 15 Oyster Bay stations was77.2 F (25.1 C)

!Recall products

!Closed Oyster Bay for harvesting of shellfish and recalledshellfish harvested from that area after August 10


!Laboratory testing of 12 V. parahaemolyticus clinicalisolates,

!Pulsed-field gel electrophoresis (PFGE) performed onfour clinical isolates! three isolates epidemiologically linked to Oyster Bay had

indistinguishable PFGE patterns,

! the other isolate not linked to Oyster Bay had a distinctlydifferent pattern

!Oysters harvested on five occasions from Oyster Baycontained V. parahaemolyticus at less than or equalto 120 colony forming units (CFU) per gram of oystermeat.! None of these environmental isolates matched the outbreak

strain or other clinical isolates by PFGE

Vibrio parahemolyticusVibrio parahemolyticus

!V. parahemolyticus prevention and control

!Education

!Proper cooking

!Cooking temperature

!Prevent cross contamination

!Separated cooking area

!National shellfish sanitation program (NSSP)

!Water quality of harvesting area


!V. cholerae serogroup O1

!Asiatic or epidemic cholera

!Disease spread by poor sanitation, resulting incontaminated water supplies

!Sporadic outbreaks cause by consumption ofshellfish and other seafood

!I llness causes by the ingestion of viable bacteria,

!Attach to the small intestine

!Produce cholera toxin

!Watery diarrhea


!V. cholerae serogroup Non-O1

!Related to V. cholerae O, but cause disease lesssevere than cholera

!Pathogenic and non-pathogenic strains are normalhabitants of marine environment

!Sporadic outbreaks cause by consumption ofoyster

!I t is not known how the organism cause theillness, although an enterotoxin is suspected


!V. vulnificus

!V. vulnificus has been isolated from a wide rangeof environmental sources (water, sediment,plankton, shellfish)

!Mostly cause wound infections and gastroenteritis

!Wound infections result from contaminating openwound

!The ingestion of V. vulnificus can result ingastroenteritis

!Septicemia form: Chronic disease, especially liverdisease

Isolation ofIsolation of Vibrio Vibrio sppspp..

!Because many food isolates are nonpathogenic,pathogenicity of all food isolates must bedemonstrated

!Bacterial culture

!Selective media

!KANAGAWA Phenomenon (K): K+ pathogenic strain

!Test in blood agar and Wagatsuma agar (contain special saltand crystal violet)

!Hemolysis of human red blood cells

!V. cholerae: test for the production of cholera toxin

listeriosis - vet.chula.ac.th · listeriosis outbreaks!in 1981, 41 cases of listeriosis including...

Documents