vibrio

• Vibrio


  • Family: Vibrionaceae
  • Environment: fresh water, brackish water, marine/ salt water
  • Indication of Vibrio spp. Infection: consumption of raw seafood, immigration or foreign travel, cholera-like or rice-water stools, trauma incurred during contact with fresh, estuarine, or marine water or associated products
• Vibrio spp.


  • Non-spore forming, facultative anaerobe, halophilic pleomorphic gram (-) bacilli
  • Broth medium: polar, sheathed flagella
  • Solid medium: peritrichous, unsheathed flagella
  • Biochemical test: Catalase (-), Oxidase (+), Reduce nitrate to nitrite, String test (+), vibriostatic compound O/129 (S)
• Vibrio spp. EXCEPT V. metschnikovii

  • 2,4-diamino-6,7 diisopropylpteridine
  • 0.5% sodium desoxycholate
  • 1-8% NaCl
• Vibrio Groups


  • Group 1: V. cholera & V. mimicus
  • Group 2: V. metscchnikovii
  • Group 3: V. cincinnatiensis
  • Group 4: G. hollisae
  • Group 5: P. damsel & V. fluvialis
  • Group 6: V. alginolyticus, V. parahaemolyticus, V. vulnificus & V. harveyi
• Vibrio cholerae


  • V. cholerae O1: Ogawa (A, B), Inaba (A, C), Hikojima (A, B, C)
  • V. cholerae O139
  • V. cholerae non-O1: resemble V. cholerae but fail to agglutinate in O1 antisera
  • V. parahaemolyticus: O and K antigens
• Vibrio cholerae O1


  Cholera, "Asiatic cholera" or "epidemic cholera"
• Enterotoxin


  Cholera toxin or choleragen
• Vibrio cholerae Biogroups


  • Classic
  • El Tor
• Vibrio cholerae non-O1 resemble toxigenic V. cholerae O1, but most lack the cholera toxin gene
• Vibrio parahaemolyticus


  • 2nd most common vibrio causing gastroenteritis
  • Pandemic strain: V. parahaemolyticus serotype O3:K6
  • Kanagawa phenomenon: heat-stable hemolysin effective in high-salt mannitol medium
• Vibrio vulnificus


  • 2nd most serious cause of Vibrio-associated type infections
  • Septicemia, Wound infections
  • Least pathogenic for humans
  • Strict halophile: 1-10% NaCl
  • Eye and ear infections or wound & burn infections
• Vibrio alginolyticus


  1. 10% NaCl
• Specimen collection


  • Body fluids, pus, tissues
  • Transport medium: Cary-Blair, Buffered glycerol saline
  • Time of collection: ASAP in the course of illness, before antimicrobial administration
• Direct microscopic examination


  Pleomorphic gram (-) bacilli
• Culture & Macroscopic Examination

  • NA & BAP
  • MAC: NLF except V. vulnificus
  • TCBS: thiosulfate citrate bile salt sucrose, selective medium
  • Differentiates sucrose-fermenting species from the nonsucrose-fermenting species
• Biochemical tests: Presumptive


  • 150 ug vibriostatic agent O/129 (S) & String test (+) to differentiate from Aeromonas
  • Ferment Inositol (-) to differentiate from Pleisiomonas EXCEPT V. cincinnatiensis & some V. metschnikovii
  • Oxidase (+) to differentiate from Enterobacteriaceae EXCEPT V. metschnikovii
  • O/F reactions (fermenter) to differentiate from oxidative Pseudomonas
• Vibrio Biochemical test: Definitive Groups

  • Group 1: V. cholerae & V. mimicus
  • Group 2: V. metscchnikovii
  • Group 3: V. cincinnatiensis
  • Group 4: G. hollisae
  • Group 5: P. damsel & V. fluvialis
  • Group 6: V. alginolyticus, V. parahaemolyticus, V. vulnificus & V. harveyi
• Vibrio Group 1 (V. cholerae & V. mimicus) do not grow in NA without additional NaCl
• Vibrio Group 2 (V. metschnikovii) is Oxidase (+), Nitrate to nitrite reduction (+)
• Aeromonas


  • Family: Aeromonadaceae
  • Oxidase (+), glucose-fermenting, gram-negative bacilli
  • Environment: freshwater, estuarine, and marine env.
  • Groups: mesophilic group (37°C), psychrophilic group (22°C)
• Aeromonas Infection


  • Gastrointestinal Infections: Acute, secretory diarrhea often accompanied by vomiting, Acute, dysenteric form of diarrhea, Chronic diarrhea, Cholera-like disease
  • Septicemia, meningitis, wound infections & keratitis associated with contact lens wear
• Aeromonas Culture


  • Large, round, raised, opaque colonies with an entire edge and a smooth, often mucoid, surface
  • BAP (beta hemolysis): A. hydrophila, A. veronii biovar sobria, and A. jandaei
  • CIN II w/ 4 µg of cefsulodin instead of 15 µg (Cefsulodin-Irgasan-Novobiocin) agar: pink-centered colonies (mannitol fermentation), with an uneven, clear apron resembling Yersinia enterocolitica
• Aeromonas Biochemical tests


  • Indole (+)
  • Oxidase (+) to differentiate from Enterobacteriaceae EXCEPT Plesiomonas
  • String test (-) & O/129 (R) to differentiate from Vibrio spp.
  • Growth in NB with 0% NaCl (+) but (-) in 6% NaCl to differentiate Aeromonas & Pleisiomonas spp. from Vibrio spp.
  • Inositol fermentation (-) & (+) Glucose fermentation w/ or w/out acid
• Erotoxigenic E. coli


  Causes septicemia, meningitis, wound infections & keratitis associated with contact lens wear
• Aeromonas


  A. caviae
• Specimen collection


  No special considerations
• Direct microscopic examination


  • Gram-negative bacilli
• Culture


  1. Large, round, raised, opaque colonies with an entire edge and a smooth, often mucoid, surface

  2. BAP (beta hemolysis): A. hydrophila, A. veronii biovar sobria, and A. jandaei

  3. CIN II w/ 4 µg of cefsulodin instead of 15 µg (Cefsulodin-Irgasan-Novobiocin) agar

  4. Pink-centered colonies (mannitol fermentation), with an uneven, clear apron resembling Yersinia enterocolitica
• Aeromonas


  • Oxidase (+)
  • Indole (+)
  • Differentiates from Enterobacteriaceae EXCEPT ____________________
  • String test (-) & O/129 (R)
  • Differentiates from Vibrio spp.
  • Growth in NB with 0% NaCl (+) but (-) in 6% NaCl
  • Differentiates Aeromonas & Pleisiomonas spp. from Vibrio spp.
  • Inositol fermentation (-) & (+) Glucose fermentation w/ or w/out acid
  • Differentiates from Pleisiomonas spp.
• Plesiomonas shigelloides


  • Family Enterobacteriaceae
  • Motile, oxidase-positive, glucose fermenting, facultatively anaerobic, gram-negative bacilli
• P. shigelloides
• Plesiomonas shigelloides infection


  • Gastroenteritis
  • Watery or secretory diarrhea
  • Subacute or chronic disease that lasts from 14 days to 2 to 3 months
  • More invasive, dysenteric form that resembles colitis
  • Bacteremia and meningitis
• Plesiomonas


  • Motile: monotrichous or two to five lophotrichous flagella
  • Cross-agglutinate with Shigella sonnei, S. dysenteriae & S. boydii
• Plesiomonas virulence factors


  • O & H antigen
• Plesiomonas microscopic examination


  • Gram-negative bacilli in singly, in pairs, or in short chains or filamentous forms
• Plesiomonas culture & macroscopic examination

  1. Shiny, opaque, nonhemolytic colonies appear, with a slightly raised center and a smooth and entire edge

  2. MAC: may be LF or NLF

  3. Oxidase test (+)

  4. Inositol Brilliant Green Bile Agar: white to pink colonies

  5. (+) growth in CIN

  6. Colonies with an opaque apron

  7. (-) growth in TCBS
• Comparison of tests for Vibrio, Aeromonas, and Pleisiomonas

  • Oxidase test
  • 150 ug O/129
  • Growth TBCS
  • 0% NaCl
  • 6.5% NaCl
  • Gelatin liquefaction
  • Glucose fermentation
  • Inositol fermentation
  • Sucrose fermentation
  • Mannitol fermentation
• Group 1 Enterobacteriaceae


  • Previously classified under vibrios (oxidase +)
  • Asaccharolytic
  • Family Campylobactereaceae
  • Campylobacter, Arcobacter, Sulfurospirillum
  • Microaerophile
  • 5% oxygen
  • Family: Helicobactereaceae
  • Helicobacter and Wolinella
• Campylobacter & Campylobacter-Like Species


  • Campylobacter spp. cause abortion in domestic animals
  • Most common cause of bacterial gastroenteritis
  • 4th most common cause of foodborne gastrointestinal illness
  • Helicobacter pylori causes gastric, peptic, and duodenal ulcers, GI carcinoma
• Specimen collection for Campylobacter & Campylobacter-Like Species

  1. C. fetus subsp. fetus: Blood culture

  2. Campylobacter spp.: Stool samples & rectal swab, Transport medium: Cary-Blair, Buffered glycerol saline (toxic to campylobacters)

  3. H. pylori: Gastric biopsy, Transport medium: Stuart medium, Tissue samples: Cysteine-Brucella broth with 20% glycerol (frozen at −70° C)