Enterobacteriaceae, Vibrio, Campylobacter And Helicobacter (2) Faculty: Dr. Alvin Fox

ENTEROBACTERIACEAE, VIBRIO, CAMPYLOBACTER AND HELICOBACTER (2) Faculty: Dr. Alvin Fox 1

Typhoid • • • • •

enteric fever severest salmonella disease Salmonella typhi rare in US epidemics – third world – Europe * historical

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Salmonella typhi • human reservoir – carrier state common

• contaminated food • water supply • poor sanitary conditions 3

Typhoid macrophage

septicemia - occurs 10-14 days – lasts 7 days

gall bladder –shedding, weeks acute phase, gastroenteritis

gastroenteritis

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S. typhi • Vi (capsular) antigen – protective

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Typhoid -Therapy • Antibiotics – essential • Vaccines – ineffective

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Yersiniosis • Yersinia entercolitica – gastroenteritis – Scandinavia common – US * colder regions

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Yersiniosis • transmission – fecal contamination, domestic animals • water • milk

– meat

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Yersinia

Gut lumen

Diarrhea fever abdominal pain antibiotic therapy recommended occassional bacteremia 9

Yersinia -isolation cold enrichment

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Y. pseudotuberculosis • similar • less severe disease

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Vibrio cholerae

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Vibrios • • • • • •

Gram negative rods comma shaped facultative anaerobes oxidase positive simple nutritional requirements readily cultivated 13

Occurrence -cholera • third world • US – uncommon * traveler * ingestion of sea-food

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Transmission - V. cholerae feces

water – fresh – salt

food

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Cholera - attachment

Gut lumen

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Cholera toxin- Choleragen • • •

B binds to gangliosides provides channel for A A catalyses ADP-ribosylation – regulator complex – activates adenylate cyclase

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Cholera -therapy • massive secretion of ions/water into gut lumen • dehydration and death • therapy – fluid replacement – antibiotic therapy • vaccination – partially effective – not generally used – international travelers 18

Vibrio parahemolyticus • raw sea-food • grows best in high salt • not common in US • diarrhea

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CAMPYLOBACTER & HELICOBACTER • Gram negative rods • curved or spiral • genetically related

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Campylobacter jejuni pleomorphic 21

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Transmission • infects the intestinal tract of animals • chickens, cattle, sheep

• Transmitted – milk – meat products 23

Campylobacter

Gut lumen

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Isolation - Campylobacter • microaerophilic • grows best 42oC

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Campylobacter - symptoms • diarrhea • malaise • fever • abdominal pain • usually self-limiting • antibiotics occassionally • bacteremia –small minority 26

Helicobacter pylori • stomach mucosa • ulcers

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Urease • Important in neutralizing stomach acid

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Diagnosis -Helicobacter • Culture - urease

NH4+ CO2

• Direct detection of urease •CO2 derived from labeled urea

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Therapy -Helicobacter • Antibiotics – cures ulcers

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Summary statement • sanitary measures – protect the water supply • food/water borne epidemics – infrequent, US – common third, world • zoonotic infections – contaminated animal or vegetable products – less well controlled than man-to-man

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Therapy • severe diarrhea – fluid replacement essential • antibiotic therapy sometimes used in local infection but always in systemic disease

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