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NAME: Aeromonas hydrophila

SYNONYM OR CROSS REFERENCE: Septicemia, Gastroenteritis Footnote 1.

CHARACTERISTICS: A. hydrophila are Gram-negative, rod-shaped facultative anaerobes Footnote 2, ranging in size from 0.3-1.0 µm wide by 1.0-3.5 µm long Footnote 1. They are motile by a single polar flagellum Footnote 1. The bacteria can produce heat-labile enterotoxins, which can be associated with haemolysin and cytotoxin production Footnote 3.


PATHOGENICITY/TOXICITY: Infection with Aeromonas hydrophila can result in gastrointestinal or non-gastrointestinal complications. Symptoms of gastrointestinal infection range from watery diarrhea to dysenteric or bloody diarrhea. Chronic infection is also possible Footnote 1. Non-gastrointestinal complications that may arise subsequent to A. hydrophila infection include hemolytic syndrome and kidney disease, cellulitis, wound and soft-tissue infection, meningitis, bacteremia and septicemia Footnote 4, Footnote 5, ocular infections, pneumonia and respiratory tract infections Footnote 6, urinary tract infection in neonates Footnote 7, osteomyelitis, peritonitis and acute cholecystitis. Severe infection can result from non resolved intermittent diarrhea, which can occur months after the initial infection Footnote 1, Footnote 2, Footnote 8. A. hydrophila can cause disease in aquatic animals, such as red leg disease in frogs which is caused by endotoxin and haemolysin produced by the bacteria and can be fatal Footnote 8, Footnote 9.

EPIDEMIOLOGY: Worldwide – Aeromonas spp. are inhabitants of aquatic ecosystems and are found in most parts of the world Footnote 1. Although the role of Aeromonas hydrophila as a causative agent of human disease is controversial, some estimated that they may cause 13 % of gastroenteritis cases in United States Footnote 10. Some jurisdictions may not identify these organisms as pathogens.

Aeromonas spp. are commonly found in ground water; drinking water at treatment plants, distribution systems, and reservoirs; and in clean and polluted lakes and rivers Footnote 1. The bacteria are found in about 1% - 27 % of drinking water Footnote 11. Aeromonas hydrophila can be found in fresh produce, meat, and dairy products. The risk of infection from oral ingestion of Aeromonas spp. is 7.3/billion for low exposure. Aeromonas spp. can also be found in soil.

HOST RANGE: Human, animals, birds, fish, and cold-blooded marine and freshwater reptiles Footnote 1, Footnote 12, Footnote 13.

INFECTIOUS DOSE: The infectious dose for humans and animals is greater than 10 10 organisms Footnote 11.

MODE OF TRANSMISSION: Infection is spread via fecal-oral transmission during direct ingestion or drinking of contaminated water or foods Footnote 1, Footnote 11, Footnote 14. Infection can also be transmitted by eating contaminated meat, dairy, shrimp, or fish Footnote 1.

INCUBATION PERIOD: The reported incubation period for Aeromonas-associated diarrhea is 1 to 2 days Footnote 15. Aeromonas’ infections contracted via recreational sporting activities, such as swimming occur as early as 24h post exposure Footnote 15. Cellulitis is the most frequent soft tissue infection and is usually accompanied by systemic signs developing within 8 to 48 h Footnote 17. The length of time from initial A. hydrophila infection to bacteremia ranges from 1 to 38 days Footnote 16.

COMMUNICABILITY: It can be transferred from human-to-human by contact with infected wounds, feces or blood Footnote 18. The pathogen can also be transferred during sports; especially when played in muddy environments involving transfer of infected soil.


RESERVOIR: Free living, water is the main reservoir Footnote 1. It can also be found in mud, water, fresh produce, meat (beef, poultry, pork, fish, shellfish, and shrimp) and dairy products Footnote 18.




DRUG SUSCEPTIBILTIY: Sensitivity has been confirmed for fluoroquinolones (ciproflaxin) Footnote 19, aminoglycosides (except streptomycin), tetracycline Footnote 20, chloramphenicol Footnote 21, carbapenems Footnote 22, polymyxin, streptomycin, gentamicin Footnote 23, and trimethoprim-sulfamethoxazole.

DRUG RESISTANCE: Almost all Aeromonas spp. are resistant to penicillin, ampicillin, amoxicillin, ticarcillin, carbenicillin, and cephalothin Footnote 21-Footnote 23.

SUSCEPTIBILITY TO DISINFECTANTS: Susceptibility has been shown for 1% sodium hypochlorite, 2% glutaraldehyde, 70% ethanol, iodines, phenolics, and formaldehyde Footnote 24. It is also sensitive to silver in water Footnote 25 and free chlorine Footnote 26.

PHYSCIAL INACTIVATION: Exposure to temperatures of 62 oC or greater for more that a few minutes is lethal to A. hydrophila. The bacteria can be inactivated by moist heat (121°C for 15 min - 30 min) and dry heat (160-170°C for 1-2 hours) Footnote 27-Footnote 29. The bacteria can also be inactivated by ultrasonic waves delivered under high pressure (200 KPa) and elevated temperatures (40 °C) Footnote 29. Simultaneous sonication at temperature higher than 70°C and 0.5 MPa is also effective Footnote 30.

SURVIVAL OUTSIDE HOST: Aeromonas hydrophila can survive in large volumes of open water, ground water, soil, as well as polluted lakes and rivers Footnote 1.


SURVEILLANCE: Monitor for symptoms. The bacteria can be detected by PCR Footnote 10. Aeromonas spp. samples can be isolated and confirmed on ampicillin dextrin agar forming yellow colour colonies Footnote 31. Confirmation by laboratory tests can be performed by oxidase test (positive), triple sugar iron agar (glucose fermenting), or Biolog detection methods Footnote 1, Footnote 31.

FIRST AID TREATMENT: Administration of antibiotics such as ciprofloxacin, co-trimoxazole, Gentamicin, or Amikacin Footnote 1. Intravenous fluid replacement in combination with oral antibiotics is effective in lessening infection symptoms Footnote 32.





SOURCES/SPECIMENS: The bacteria have been isolated from feces, sputum, urine, bile, pus, surgical wounds, medicinal leeches, normal flora, spleen, pleural fluid, placenta, skin lesion, throat, gall bladder, hospital water supplies, dialysis fluids, and blood plasma products Footnote 14, Footnote 33, Footnote 34.

PRIMARY HAZARD: Ingestion, accidental inoculation, direct contact with contaminated areas Footnote 11, Footnote 18.

SPECIAL HAZARDS: A. hydrophila is found in reptiles Footnote 13 and aquatic animals Footnote 1, thus it can be a potential hazard when working with these animals in a laboratory environment.


RISK GROUP CLASSIFICATION: Risk Group 2 Footnote 35.

CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures Footnote 36.

PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 36.

OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities Footnote 36.


SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up Footnote 36.

DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism before disposing by autoclave, chemical disinfection, gamma irradiation, or incineration Footnote 36.

STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labeled Footnote 36.


REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.

UPDATED: December 2011

PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada

Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.

Copyright ©
Public Health Agency of Canada, 2011


Footnote 1
Horneman, A. J., Ali, A., & Abbott, S. L. (2007). Aeromonas. In P. R. Murray, E. J. Baron, M. L. Landry, J. H. Jorgensen & M. A. Pfaller (Eds.), Manual of Clinical Microbiology (9th ed., pp. 715-722). Washington, D.C.: ASM Press.

Footnote 2
Collier, L., Balows, A., & Sussman, M. (Eds.). (1998). Microbiology and Microbial Infection :Systematic Bacteriology (9th ed.). USA:

Footnote 3
Burke, V., Robinson, J., Atkinson, H. M., Dibley, M., Berry, R. J., & Gracey, M. (1981). Exotoxins of Aeromonas hydrophila. The Australian Journal of Experimental Biology and Medical Science, 59(Pt 6), 753-761.

Footnote 4
Chang, C. Y., Thompson, H., Rodman, N., Bylander, J., & Thomas, J. (1997). Pathogenic analysis of Aeromonas hydrophila septicemia. Annals of Clinical and Laboratory Science, 27(4), 254-259.

Footnote 5
Reines, H. D., & Cook, F. V. (1981). Pneumonia and bacteremia due to Aeromonas hydrophila. Chest, 80(3), 264-267.

Footnote 6
Borger van der Burg, B. L., Bronkhorst, M. W., & Pahlplatz, P. V. (2006). Aeromonas hydrophila necrotizing fasciitis. A case report. The Journal of Bone and Joint Surgery.American Volume, 88(6), 1357-1360. doi:10.2106/JBJS.C.00923

Footnote 7
Bartolome, R. M., Andreu, A., Xercavins, M., Elcuaz, R., & Salcedo, S. (1989). Urinary tract infection by Aeromonas hydrophila in a neonate. Infection, 17(3), 172-173.

Footnote 8
Pikul, J., & et al. (2009). A highly virulent pathogen, Aeromonas hydrophilia from fresh water crayfish Pacifastacus leniusculus. Journal of Invertebrate Pathology., 101(1), 56-66.

Footnote 9
Rigney, M. M., Zilinsky, J. W., & Rouf, M. A. (1978). Pathogenicity of A eromonas hydrophila in Red Leg Disease in Frogs. Current Microbiology, 1, 175-179.

Footnote 10
Kingombe, C., & et al. (1999). PCR Detection, Characterization, and Distribution of Virulence Genes in Aeromonas spp. Applied and Environmental Microbiology, 65(12), 5293-5302.

Footnote 11
Rusin, P. A., & et al. (1997). Risk assessment of opportunistic bacterial pathogens in drinking water. Rev Environ Contam Toxicol., 152, 57-83.

Footnote 12
Glunder, G., & Siegmann, O. (1989). Occurrence of Aeromonas hydrophila in wild birds. Avian Pathology : Journal of the W.V.P.A, 18(4), 685-695. doi:10.1080/03079458908418642

Footnote 13
Fulton, M.The bacterium Aeromonas hydrophila from lizards of the genus Anolis in Puerto Rico. Louisiana State University Medical Center.

Footnote 14
Udeh, P. J. (2004). A Guide to Healthy Drinking Water. USA: iUniverse Inc.

Footnote 15
Janda, J. M., & Abbott, S. L. (2010). The genus Aeromonas: taxonomy, pathogenicity, and infection. Clinical Microbiology Reviews, 23(1), 35-73. doi:10.1128/CMR.00039-09

Footnote 16
Hochedez, P., Hope-Rapp, E., Olive, C., Nicolas, M., Beaucaire, G., & Cabie, A. (2010). Bacteremia caused by Aeromonas hydrophila complex in the Caribbean Islands of Martinique and Guadeloupe. The American Journal of Tropical Medicine and Hygiene, 83(5), 1123-1127. doi:10.4269/ajtmh.2010.10-0063

Footnote 17
Adamski, J., Koivuranta, M., & Leppanen, E. (2006). Fatal case of myonecrosis and septicaemia caused by Aeromonas hydrophila in Finland. Scandinavian Journal of Infectious Diseases, 38(11-12), 1117-1119. doi:10.1080/00365540600684389

Footnote 18
Hassan, V., & et al. (2004). Outbreak of Aeromonas hydrophila Wound Infections Associated with Mud Football. Clinical Infectious Diseases., 38, 1084-1089.

Footnote 19
Ko, W. C., Chiang, S. R., Lee, H. C., Tang, H. J., Wang, Y. Y., & Chuang, Y. C. (2003). In vitro and in vivo activities of fluoroquinolones against Aeromonas hydrophila. Antimicrobial Agents and Chemotherapy, 47(7), 2217-2222.

Footnote 20
Fass, R. J., & Barnishan, J. (1981). In vitro susceptibilities of Aeromonas hydrophila to 32 antimicrobial agents. Antimicrobial Agents and Chemotherapy, 19(2), 357-358.

Footnote 21
Geiss, H., & Freij, B. (1989). Aeromonas As A Human Pathogen. Critical Reviews in Microbiology, 16(4), 253-386.

Footnote 22
Saavedra, M. J., Guedes-Novais, S., Alves, A., Rema, P., Tacao, M., Correia, A., & Martinez-Murcia, A. (2004). Resistance to beta-lactam antibiotics in Aeromonas hydrophila isolated from rainbow trout (Oncorhynchus mykiss). International Microbiology : The Official Journal of the Spanish Society for Microbiology, 7(3), 207-211.

Footnote 23
Overman, T. L. (1980). Antimicrobial Susceptibility of Aeromonas hydrophila. ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 17(4), 612-614.

Footnote 24
Laboratory Safety Manual (1993). (2nd ed.). Geneva: World Health Organization.

Footnote 25
Silvestry-Rodriguez, N., Bright, K. R., Uhlmann, D. R., Slack, D. C., & Gerba, C. P. (2007). Inactivation of Pseudomonas aeruginosa and Aeromonas hydrophila by silver in tap water. Journal of Environmental Science and Health Part A,42(11), 1579-1584.

Footnote 26
Massa, S. (2003). Susceptibility to chlorine of Aeromonas hydrophila strains. Journal of Applied Microbiology, 86(1), 169-173.

Footnote 27
Erickson, M. C., & Ortega, Y. R. (2006). Inactivation of protozoan parasites in food, water, and environmental systems. Journal of Food Protection, 69(11), 2786-2808.

Footnote 28
Pflug, I. J., Holcomb, R. G., & Gomez, M. M. (2001). Principles of the Thermal Destruction of Microorganisms. In S. S. Block (Ed.), Disinfection, Sterilization, and Preservation (5th ed., pp. 79-129). Philadelphia, USA: Lippincott Williams & Wilkins.

Footnote 29
PAGA´N, R. P. (1999). Bacterial Resistance to Ultrasonic Waves under Pressure at Nonlethal (Manosonication) and Lethal (Manothermosonication) Temperatures. APPLIED AND ENVIRONMENTAL MICROBIOLOGY, , 297-300.

Footnote 30
Cohen, M. L. (2001). Emerging Infectious Diseases. In S. S. Block (Ed.), Disinfection, Sterilization and Preservation (5th ed., pp. 870). Florida, USA: Lipincott Williams & Wilkins.

Footnote 31
Chauret, C. (2001). Detection of Aeromonas hydrophila in a drinking water distribution system: a field and pilot study. Can. J. Microbiol., 47(8), 782-786.

Footnote 32
Nathwani, D., Laing, R. B., Harvey, G., & Smith, C. C. (1991). Treatment of symptomatic enteric aeromonas hydrophila infection with ciprofloxacin. Scandinavian Journal of Infectious Diseases, 23(5), 653-654.

Footnote 33
Gilardi, G. L. (1967). Morphological and biochemical characteristics of Aeromonas punctata (hydrophila, liquefaciens) isolated from human sources. Applied Microbiology, 15(2), 417-421.

Footnote 34
Trust, T. (1979). Clinical Involvement of Aeromonas hydrophila. CMA Journal, 120

Footnote 35
Human pathogens and toxins act. S.C. 2009, c. 24, Second Session, Fortieth Parliament, 57-58 Elizabeth II, 2009. (2009).

Footnote 36
Public Health Agency of Canada. (2004). In Best M., Graham M. L., Leitner R., Ouellette M. and Ugwu K. (Eds.), The Laboratory Biosafety Guidelines (3rd ed.). Canada.