title: Involvement of Enterobacter cloacae in the mortality of the fish, Mugil cephalus.
abstract: OBJECTIVE
  To identify the causative agent of the mortality in the fish, Mugil cephalus, in Muttukadu lagoon.
  
  
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Aquatic Animal Health Division, Central Institute of Brackishwater Aquaculture, Chennai, India.
authors.forename: V Thillai
authors.initials: VT
authors.lastname: Sekar
authors.forename: T C
authors.initials: TC
authors.lastname: Santiago
authors.forename: K K
authors.initials: KK
authors.lastname: Vijayan
authors.forename: S V
authors.initials: SV
authors.lastname: Alavandi
authors.forename: V Stalin
authors.initials: VS
authors.lastname: Raj
authors.forename: J J S
authors.initials: JJ
authors.lastname: Rajan
authors.forename: M
authors.initials: M
authors.lastname: Sanjuktha
authors.forename: N
authors.initials: N
authors.lastname: Kalaimani
mesh_terms: D000818:Animals; D001483:Base Sequence; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D016972:Enterobacter cloacae / Q000235:genetics / Q000302:isolation & purification / Q000472:pathogenicity*; D004756:Enterobacteriaceae Infections / Q000382:microbiology / Q000401:mortality / Q000473:pathology / Q000662:veterinary*; D005393:Fish Diseases / Q000382:microbiology* / Q000401:mortality / Q000473:pathology; D007194:India; D007684:Kidney Tubules / Q000473:pathology; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D023701:Smegmamorpha / Q000382:microbiology*
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S