Isolation and virulence gene profiling of Clostridium perfringens from freshwater fish
Najimaana Wani, Shakeel Ahmad Wani, ZH Munshi, Showkat Ahmad Shah, Mudasir Rather, Akram Hussain, Zahid Kashoo and Nusrat Nabi Khan
The present study was undertaken to isolate and study the virulence gene profile of C. perfringens from freshwater fish in Srinagar city (local fish: Schizothorax spp, Cyprinus carpio andexotic carp like common carp, silver carp, Rohu, Pangus). Of the total of 110 randomly collected fish samples processed anaerobically for the presence of C. perfringens,13 (11.81%) samples were found positive for the organism. The higher prevalence was observed in locally available fish collected from different markets of the Srinagar city (18.18%) as compared to fish imported from other states of the country (5.45%). The level of contamination among two types of fish samples was statistically significant with higher levels of contamination in locally available fish (p<0.05). The virulence gene profiling of the isolates was studied using multiplex-PCR targeting cpa, cpb, etx, iap, cpb2 and cpe genes. The cpa gene was detected in all 13 isolates (100%), either alone in 7 isolates (53.84%) or in combination with the cpb2 gene in 5 isolates (38.46%) and with cpe gene in 1 isolate (7.69%). None of the isolates screened carried cpb, etx or iap gene confirming the occurrence of C. perfringens toxinotype A and thereby the absence of toxinotypes B, C, D and E. The study regarding isolation and molecular characterization of C. perfringens from fish especially from Srinagar was conducted for the first time as well as from other regions of India are very scanty. The present findings suggest that fish may be considered as a potential source of C. perfringens type A infection to human populations through food chain.