Involvement of Enterobacter cloacae in the mortality of the fish, Mugil cephalus

Abstract

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.

Microbial and toxic evaluation of raw and treated olive oil mill wastewaters

“…During this experimental study, the most frequently encountered species in the raw effluent was Enterobacter cloacae (65%), which is a clinically significant Gram‐negative, facultative‐anaerobic, rod‐shaped bacterium belonging to the family of Enterobacteriaceae and is widely distributed in nature;25 it is also the only species that appears in the treated effluent as well. The gram‐negative bacteria Pseudomonas aeruginosa, Serratia odorifera and Aeromonas hydrophila were also found, with the later species being facultative anaerobic 26…”

“…Enterobacter cloacae has been shown to be pathogenic to fish due to the fact that this species is not part of the normal flora in the intestinal tract of fish, so its presence is associated with polluted waters 25. As shown in Tables 5 and 6, the correlation between the presence of E. cloacae and the LC 50 values of T. platyurus depicts the negative effect of this microbe on other freshwater organisms as well.…”

The Alteration of Intestinal Microbiota Profile and Immune Response in Epinephelus coioides during Pathogen Infection

“…In addition, Terrisporobacter was formerly known as a pathogen in humans [74]. The genera Enterovibrio, Delftia, Endozoicomonas and Ruminococcus were abundant in the Vibrio group; these genera are opportunistic bacterial pathogens in both humans and fish [75][76][77][78][79][80]. After infection with GIV, the intestinal microbiota was associated with a wide range of Aureispira, Eubacterium hallii, Bacteroides, Parasutterella, Rubritalea and Fusicatenibacter.…”

Molecular characterization and antimicrobial resistance profile of fecal contaminants and spoilage bacteria that emerge in rainbow trout (<i>Oncorhynchus mykiss</i>) farms

“…Aquaculture waters can be polluted when urban wastes mix with farm water, resulting in contamination with coliforms and other pollutants [2]. Both fresh and sea water fishes can harbor human/animal pathogenic bacteria, particularly those of the coliform group [4,5,6]. Fecal coliforms, such as Enterobacter cloacae , are not among the normal intestinal flora of fish and usually originate from the feces of warm-blooded animals; hence their presence in infected fish or aquaculture water supplies indicates environmental pollution [6, 7].…”