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Three species of Aeromonas ( A. dhakensis, A. hydrophila and A. jandaei ) isolated from freshwater crocodiles ( Crocodylus siamensis ) with pneumonia and septicemia
Author(s) -
Pu W.,
Guo G.,
Yang N.,
Li Q.,
Yin F.,
Wang P.,
Zheng J.,
Zeng J.
Publication year - 2019
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/lam.13112
Subject(s) - aeromonas hydrophila , biology , pneumonia , microbiology and biotechnology , antibiotics , crocodylus , aeromonas , virulence , sepsis , veterinary medicine , bacteria , immunology , crocodile , medicine , ecology , biochemistry , genetics , gene
Hundreds of farmed Siamese crocodiles ( Crocodylus siamensis ) died during July 2016 at a farm in Wenchang, Hainan, China. In two necropsied crocodiles, we observed symptoms of dermatorrhagia, hepatomegaly and hepatic congestion. Pulmonitis was diagnosed by pulmonary congestion and pulmonary fibrinous exudate. Septicaemia was diagnosed by isolation of three Aeromonas species from blood and visceral tissues; A. dhakensis , A. hydrophila and A. jandaei were identified by biochemical and molecular tests. We used a zebrafish model to determine the half‐maximal lethal dose ( LD 50 ), and A. dhakensis was found to be the most virulent species, with an LD 50 of 8·91 × 10 5 CFU per ml. The results of a drug sensitivity test indicated that these species were sensitive to 11 antibiotics. This is the first report of A. dhakensis , A. hydrophila and A. jandaei being isolated from a mixed infection in Siamese crocodiles. Significance and Impact of the Study In this study, we isolated three species of Aeromonas ( A. dhakensis , A. hydrophila and A. jandae ) from farmed Siamese crocodiles with fatal fibrinous pneumonia and septicaemia. This is the first description of a mixed infection with three Aeromonas species among captive crocodilians.