Faculty: Dr. Alvin Fox

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Enterobacteriaceae II Vibrio, Campylobacter,
Helicobacter (Gram negative rods, enteric tract),
Lecture 35
Faculty Dr. Alvin Fox
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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

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Typhoid

• septicemia
• - occurs 10-14 days
• lasts 7 days

macrophage

• 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
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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

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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

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Vibrio parahemolyticus

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

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Vibrio vulnificus

• Wound infections
• Most common Vibrio infection in the US

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CAMPYLOBACTER HELICOBACTER

• Gram negative rods
• curved or spiral
• genetically related

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Campylobacter jejuni
pleomorphic
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Transmission

• infects the intestinal tract of animals
• chickens, cattle, sheep
• Transmitted
• milk
• meat products

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Campylobacter
Gut lumen
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Isolation - Campylobacter

• microaerophilic
• grows best 42oC

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Campylobacter - symptoms

• diarrhea
• dysentery common
• malaise
• fever
• abdominal pain
• usually self-limiting
• antibiotics occasionally
• bacteremia
• small minority

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Helicobacter pylori

• stomach mucosa
• ulcers

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Diagnosis -Helicobacter

• Culture
• - urease NH4 CO2
• Direct detection of urease
• CO2 derived from labeled urea

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Urease

• Important in neutralizing stomach acid
• - pathogenesis

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Therapy -Helicobacter

• Antibiotics
• cures ulcers

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Summary statement

• sanitary measures
• largely protect the water supply
• the food supply (fresh animal and vegetable
  products) is not as well handled but this is more
  challenging
• microbiological monitoring of food is much more
  difficult than identification of infectious
  agents in clinical specimens
• food/water borne epidemics
• less common, US
• common, third world
• availability of medical care is of course higher
  in US

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Therapy

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