Clostridium perfringens from fresh water fish of Kashmir Himalaya and their aquatic environment: Toxinotyping and phylogenetic analysis.

Clostridium perfringens is a common anaerobic foodborne pathogen known to produce >20 toxins. In nature, this bacterium has 7 different toxinotypes (A-G) based on the presence of its 6 main toxins. The present study examined the occurrence of different toxinotypes of this bacterium in the ichthyofauna and aquatic environments of Kashmir Himalayan lakes, India. A total of 510 samples (210 water; 150 each of common carp and snow trout) were collected from 3 different lacustrine habitats (Dal, Anchar and Nigeen Lakes) of the region. By performing 16S rRNA PCR test, it was observed that all 210 water samples and 80 (26.66%) of 300 fish samples tested for this specific bacterial species were positive. Then by using multiplex-PCR targeting six virulence genes of C. perfringens, it was confirmed that all the 290 isolates from water and fish samples were positive for Toxinotype A, as only cpa toxin gene was amplified. Phylogenetic analysis of the amplified gene and its amino-acid sequences revealed 95%-98% homology with analogous sequences of this bacterial strain reported from China, Egypt and India. The study documents the existence of C. perfringens toxinotype A in the ichthyofauna of Kashmiri Himalayan lakes, entailing that fish can likely act as transmission medium for C. perfringens food poisoning to humans via food.