Aeromonas hydrophilia

Compiled By: Julie A. Albrecht, Ph.D., Associate Professor

The Organism: Since 1968, Aeromonas hydrophilia has been recognized as an opportunistic pathogen in immunocompromised hosts (patients on drug therapy, elderly, young). More recently it has been demonstrated to cause foodborne illness in healthy people.

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Sources of the organism:

  • Normal microflora of water

Associated foods:

  • Seafood including oysters
  • Water

Microorganism Characteristics: Gram negative facultative anaerobic rod that can be psychrophilic. Aeromonas can produce enterotoxins.

Growth conditions:

  • Temperature range: -5.3 - 43°C (109°F)
  • Optimum Temperature: 28°C (83°F)
  • pH range: 4-10
  • Lowest reported Aw for growth: 0.94
  • Salt Tolerance: 4%
  • Some evidence of chlorine resistance

The Disease: Aeromonas has been reported as the cause of food borne infections in other countries and with the increase of international travelers, this organism is considered an emerging pathogen in the United States. Only a limited number of foodborne illness outbreaks have been published.

Symptoms include:

  • Diarrhea
  • Vomiting

Onset time:

  • 6-48 hours

Infective Dose:

  • >100 cells per 100 ml of water has been reported to cause an illness

Duration of symptoms:

  • Not reported


  • Use properly treated water.
  • Thoroughly cooking foods.
  • Due to the psychrophilic nature of Aeromonas, extended shelf-life refrigerated foods need to be handled and stored properly.