Three species of Aeromonas (A. dhakensis, A. hydrophila and A. jandaei) isolated from freshwater crocodiles (Crocodylus siamensis) with pneumonia and septicemia. (11th February 2019)

• Record Type: Journal Article
• Authors: Pu, W.; Guo, G.; Yang, N.; Li, Q.; Yin, F.; Wang, P.; Zheng, J.; Zeng, J.
• Is Part Of: Letters in applied microbiology. Volume 68:Number 3(2019)
• Page Start: 212
• Page End: 218
• Publication Date: 2019-02-11
• Subjects: Aeromonas dhakensis -- Aeromonas hydrophila -- Aeromonas jandaei -- Crocodylus siamensis -- LD 50 -- mixed infection; Microbiology -- Periodicals; 660.62
• DOI: 10.1111/lam.13112
• Languages: English
• ISSNs: 0266-8254

Abstract

Abstract: 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 (LD50 ), and A. dhakensis was found to be the most virulent species, with an LD50 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. Abstract : 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.