11 Questions
What type of flagella do Vibrio spp. have?
Monotrichous flagella
What is the purpose of adding salt to the growth medium of Vibrio spp.?
To stimulate the growth of the bacteria
What is the characteristic appearance of Vibrio spp. under direct microscopy?
Fish in stream
Which of the following is a characteristic of V. parahaemolyticus?
Associated with the 'Kanagawa phenomenon'
What is the purpose of the string test in the biochemical identification of Vibrio spp.?
To detect the presence of urease enzyme
Which of the following Vibrio spp. is associated with ear infections and wound infections?
V. alginolyticus
What is the primary mode of transmission of Vibrio cholerae?
Ingestion of contaminated water or food
What is the toxin responsible for the symptoms of cholera?
Cholera toxin (choleragen)
Which of the following is a characteristic of Vibrio cholerae colonies on BAP?
Large, round, raised, and beta hemolytic
Which Campylobacter species is associated with abortion in animals?
C.fetus
What is the characteristic shape of Campylobacter spp.?
Curved, S-shape or sea-gull's wing
Study Notes
Vibrio Spp.
- Ubiquitous, curved, gram-negative rods, non-sporeformers, motile with monotrichous flagella
- Oxidase positive, growth is stimulated in the presence of salt (halophilic) except for V.cholerae and V.mimicus
- Laboratory diagnosis:
- Direct microscopy: "fish in stream" appearance
- Culture: enrichment broth (APW), translucent colonies on MAC, and yellow colonies on TCBS
- Biochemical ID: catalase and oxidase positive, string test positive
Vibrio Cholerae
- Salt requirement: non-halophilic
- Virulence factors: polysaccharide capsule, urease enzyme (in few strains)
- TCBS: green colonies (sucrose NF)
- Swarming on BAP
- Associated with "Kanagawa phenomenon"
- Serogroups: O1, O139, Non-O1/O139
- V.cholerae O1 serotype: Inaba (Philippines), Ogawa (India), Hikojima (Japan)
- V.cholerae O1 biotype: Classical, El Tor
Vibrio Parahaemolyticus
- Salt requirement: halophilic
- First reported in Japan to cause large food poisoning outbreak ("Summer diarrhea")
- Virulence: polysaccharide capsule, urease enzyme (in few strains)
Vibrio Vulnificus
- Causes wound infections and septicemia, involvement in gastroenteritis is uncertain
- Lactose fermenter
Vibrio Alginolyticus
- Causes ear infections, wound infections, and rare cause of septicemia
- Transmitted via exposure of wound to contaminated water
Aeromonas Spp.
- Ubiquitous, oxidase-positive, glucose-fermenting, gram-negative rods
- Virulence factors: cholera toxin (choleragen), Zonula occludens toxin, toxin coregulated pili
- Causes: "Rice watery stool" diarrhea, gastroenteritis, wound infections, bacteremia, HUS (Shiga-like toxin)
- Growth is not stimulated by NaCl
- BAP: large, round, raised, opaque, beta hemolytic colonies
Campylobacter Spp.
- Motile (monotrichous), nonsporing, microaerophilic, curved gram-negative rods
- S-shape/ Sea-gull's wing appearance
- Causes: Diarrhea and gastroenteritis in humans (C.jejuni, C.coli, C.upsaliensis, C.lari, C.hyointestinalis)
- Causes: Abortion in animals (C.fetus)
- Triggers the pathogenesis of various other diseases such as Guillain-Barré syndrome (C.jejuni)
Test your knowledge on Vibrio species, including their characteristics, laboratory diagnosis, and identification methods. Learn about the key features of these non-enteric gastrointestinal pathogens and how they are differentiated from other microorganisms.
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