Involvement of Enterobacter cloacae in the mortality of the fish, Mugil cephalus
Article first published online: 14 APR 2008
© 2008 The Authors. Journal compilation © 2008 The Society for Applied Microbiology
Letters in Applied Microbiology
Volume 46, Issue 6, pages 667–672, June 2008
How to Cite
Thillai Sekar, V., Santiago, T.C., Vijayan, K.K., Alavandi, S.V., Stalin Raj, V., Rajan, J.J.S., Sanjuktha, M. and Kalaimani, N. (2008), Involvement of Enterobacter cloacae in the mortality of the fish, Mugil cephalus. Letters in Applied Microbiology, 46: 667–672. doi: 10.1111/j.1472-765X.2008.02365.x
- Issue published online: 14 APR 2008
- Article first published online: 14 APR 2008
- 2007/0191: received 3 February 2008, revised 10 March 2008 and accepted 11 March 2008
- cationic factor;
- Ent. cloacae;
- enteric pathogen;
- M. cephalus;
- 16S rRNA
Aims: To identify the causative agent of the mortality in the fish, Mugil cephalus, in Muttukadu lagoon.
Methods and Results: An enteric bacterium from the kidneys of moribund fish M. cephalus, was isolated and identified as Enterobacter cloacae (MK). Mugil cephalus was experimentally infected by this isolate and was re-isolated from the kidneys of the moribund fish. Enterobacter cloacae isolates from the lagoon water (MW1, MW2 and reference strain ATCC 13047) and the reference strain were not able to induce similar pathogenesis. The putative factor imparting pathogenicity to the MK isolate was identified as a cationic molecule, which migrated towards the cathode on agarose gel electrophoresis.
Conclusions: The Ent. cloacae (MK) isolate harbouring a cationic factor was the causative agent for the mortality of M. cephalus, found in Muttukadu lagoon.
Significance and Impact of the Study: This study reveals that human enteric bacteria MK which is considered as nonpathogenic to fish, may become pathogenic to fish when it harbours this cationic factor. This cationic factor is found to be pathogenic to the fish M. cephalus leading to mortality. It was also found to be pathogenic to mice. Therefore, the shuttling of Ent. cloacae, harbouring cationic factor, between human and fish may be of human health importance.