Aeromonas, campylobacter

• What is the genus of the bacteria discussed in the study material?

  Aeromonas spp.
• Where can Aeromonas spp. be found?

  In freshwater, estuarine, and chlorinated water
• Are Aeromonas spp. part of the human flora?

  No, they are not part of the human flora
• What type of anaerobe is Aeromonas spp.?

  Facultative anaerobe
• What diseases are caused by Aeromonas spp.?


  They are responsible for a variety of diseases among warm- and cold-blooded animals
• What is the causative agent of "red-leg" disease?

  Aeromonas spp.
• What syndrome does Aeromonas spp. cause in humans?

  A nebulous syndrome known as "traveler's diarrhea"
• What is the shape and Gram stain result of Aeromonas spp.?

  Gram-negative straight rods
• What type of colonies do Aeromonas spp. form on CIN agar?

  "Bull's eye colonies" with an apron-like pattern
• What is the appearance of Aeromonas spp. colonies on BAP?

  Large, round, raised, white, and opaque colonies
• Is Aeromonas spp. a lactose fermenter?

  Yes, it is a lactose fermenter on MAC agar
• What are the biochemical test results for Aeromonas spp. regarding oxidase and catalase?

  Both oxidase and catalase tests are positive
• What is the motility characteristic of Aeromonas spp.?

  Motile with a single polar flagellum, but some species are nonmotile
• What temperature range can Aeromonas spp. typically grow in?

  From 4°C to 42°C
• How does Aeromonas spp. respond to NaCl concentrations?

  It will grow in media with 0% NaCl but not in 6% NaCl
• What is the result of the string test for Aeromonas spp.?

  Negative
• What is the fermentation result for inositol in Aeromonas spp.?

  Positive
• Which Aeromonas spp. are indole positive?


  1. caviae, A. hydrophila, A. veronii
• What are the TSI results for A. caviae?


  A/A, (-) gas, (-) H2S
• What are the TSI results for A. hydrophila and A. veronii?

  A/A, (+) gas, (+) H2S
• What are the key biochemical and physiologic characteristics of Aeromonas spp.?

  • Oxidase and Catalase positive
  • Glucose fermenters
  • Motile with single polar flagellum (some nonmotile)
  • Growth from 4°C to 42°C
  • Grows in 0% NaCl, not in 6% NaCl
  • Negative String test
• What are the complications associated with Aeromonas spp. infections?

  Hemolytic-uremic syndrome and kidney disease
• What types of infections can Aeromonas spp. cause?

  Gastroenteritis, septicemia, meningitis, keratitis, and wound infections
• What are the groups of Aeromonas spp. based on temperature preferences?

  • Mesophilic Group:
  • A. hydrophila complex
  • A. veronii complex
  • A. caviae complex
  • Psychrophilic Group:
  • A. salmonicida (fish pathogen)
• What is the characteristic of A. salmonicida?

  It is a fish pathogen and non-motile
• What is the optimal growth temperature for A. caviae?

  22°C to 25°C
• What infections are commonly caused by A. hydrophila?

  Gastroenteritis and cellulitis
• What are the differential characteristics of Vibrio, Aeromonas, and Plesiomonas regarding the oxidase test?

  • Vibrio: +/-
  • Aeromonas: -/+
  • Plesiomonas: +
• What are the differential characteristics of Vibrio, Aeromonas, and Plesiomonas regarding growth in NaCl?

  • Vibrio: + in 0% NaCl, + in 6% NaCl
  • Aeromonas: - in 0% NaCl, - in 6% NaCl
  • Plesiomonas: + in 0% NaCl, - in 6% NaCl
• What is the only species in the genus Plesiomonas?

  Plesiomonas shigelloides
• What is the mode of acquisition for Plesiomonas spp.?

  Ingestion of undercooked oysters, clams, and shrimps, and also water
• What is the growth requirement for Plesiomonas spp.?

  Minimum growth requirement of 8°C
• What is the microscopy characteristic of Plesiomonas spp.?

  Gram-negative straight bacilli
• What is the appearance of Plesiomonas spp. colonies on BAP?

  Shiny, opaque, smooth, and nonhemolytic
• What is the biochemical test result for Plesiomonas spp. regarding catalase?

  Catalase positive
• What is the TSI reaction for Plesiomonas spp.?

  K/A, (-) gas, (-) H2S
• What are the antigenic structures of Plesiomonas spp.?

  • Somatic O
  • Flagellar H
• What are the general characteristics of Campylobacter spp.?

  Motile by a single polar flagellum, non-sporeforming, and grows in 5-10% oxygen
• What is the significance of Campylobacter spp. in relation to Guillain-Barre syndrome?


  It is the most recognized antecedent cause of Guillain-Barre syndrome
• What type of bacteria are Campylobacter spp. in terms of oxygen requirement?

  Microaerophilic, except for C. rectus and C. carvus which are strict anaerobes