Vibrio spp.
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Bacteria - Gram Negative
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- Neisseria gonorrhoeae
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- Enterohemorrhagic E. Coli (EHEC)
- Enterotoxigenic E. Coli (ETEC)
- Klebsiella pneumoniae
- Campylobacter jejuni
- Vibrio spp.
- Helicobacter pylori
- Borrelia burgdorferi (Lyme Disease)
- Leptospira interrogans
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- Treponema pallidum: Diagnosis
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- Rickettsia rickettsii
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Vibrio spp.
- Includes Vibrio cholerae, Vibrio parahemolyticus, Vibrio vulnificus
- Characteristics
- Gram negative comma-shaped rod
- First test in algorithm, narrows scope of bacteria
- Oxidase +
- All gram negative curved rods are oxidase positive
- Grows in alkaline media
- Specific to Vibrio cholerae
- Motile (has flagella)
- Can grow in highly alkaline environments
- TCBS (thiosulfate-citrate-bile salt) agar is selective for Vibrio
- Gram negative comma-shaped rod
- Virulence factors
- Cholera toxin (choleragen)
- exotoxin permanently activates Gs
- increased cAMP levels promotes fluid secretion (e.g. causing diarrhea)
- Cholera toxin (choleragen)
- Transmission
- Endemic to developing countries
- In US, caused by ingestion of contaminated water or shellfish (e.g. oysters)
- Infectious dose (ID50) is high
- Acid-labile (inactivated by gastric acid) → Requires a large inoculum (dose)
- Note: taking PPIs or other acid-lowering medications will increase risk
- Presentation: Cholera
- Produces profuse rice-water diarrhea via Cholera enterotoxin
- Exotoxin increased ion secretion, resulting in secretory diarrhea and water efflux
- Does not invade GI mucosa (usually does not cause bloody diarrhea) -- watery diarrhea is purely toxin-mediated
- Produces profuse rice-water diarrhea via Cholera enterotoxin
- Diagnosis
- Stool culture in alkaline media
- No WBCs or RBCs seen in stool (no invasion of GI mucosa occurs)
- Stool culture in alkaline media
- Treatment
- Aggressive rehydration
- IV fluids
- Oral rehydration solution
- Antibiotics only used in severe cases as adjunct treatment
- macrolides, fluoroquinolones, and tetracyclines may be used (UTD)
- Aggressive rehydration