Aeromonas hydrophila-associated skin lesions and septicaemia in a Nile crocodile (Crocodylus niloticus)

Aeromonas hydrophila is one of the most common bacteria associated with the aquatic environment. There are, however, limited data on A. hydrophila infection in crocodilians. The aim of this report is to describe a case of skin lesions and septicaemia associated with A. hydrophila in a Nile crocodile (Crocodylus niloticus). A captive male crocodile in the Zoological Park of Antalya (Turkey) was found dead without showing signs of any disease. Gross examination showed brown or red-spotted skin lesions of varying size. These lesions were mostly scattered over the abdomen and occasionally on the tail and feet. At necropsy, numerous white, multifocal and randomly distributed areas were seen on the liver. Gram-stained smears from skin and liver lesions showed Gram-negative bacilli arranged in clusters. Pure cultures of A. hydrophila were recovered from skin, internal organs and blood. Isolates were found to be susceptible to ceftiofur, amoxicillin + clavulanic acid, oxytetracycline, enrofloxacin, danofloxacin, neomycin, gentamicin, and lincomycin + neomycin. A pathogenicity test was performed using this isolate on 4 male 2-year-old New Zealand white rabbits. Local abscesses formed in 2 rabbits injected subcutaneously and the 2 that were injected intraperitoneally died as a result of septicaemia. In conclusion, this report has shown that A. hydrophila may cause skin lesions and even death due to septicaemia in crocodiles.