Detection of enterotoxigenic isolates of Bacillus cereus from non-enterotoxigenic in Schizothorax zarudnyi by PCR

Bacillus cereus is a Gram-positive aerobic or facultative anaerobic, spore-forming bacterium that is widely distributed environmentally. The organism causes emetic and diarrheal food poisoning syndromes. This study was aimed at determining the of enterotoxigenic hblA gene carried by B. cereus strains isolated from Schizothorax zarudnyi samples in Iran using specific primers. PCR is a rapid and prompt method for detection of presence of enterotoxigenic B. cereus in food, to ensure that food products are safe for consumption. We provided 35 Schizothorax zarudnyi from Chah nime in sistan. Selective plating on polymixin-pyruvate-egg yolk-mannitol-bromocresol purple agar (PEMPA) was used for isolation of B. cereus from Schizothorax zarudnyi. Enterotoxin producing ability of all 13 isolates obtained from the samples was judged by reverse passive latex agglutination (RPLA) test and the presence of hblA gene was screened by PCR. B. cereus and enterotoxigenic B. cereus were found to be in 37.2 and 25.8 per cent of fish samples, respectively. All the diarrhoeal enterotoxin producing isolates showed the presence of hblA gene, but hblA gene was not present in any of the non-enterotoxigenic isolates tested in this study. This indicated that the data of hblA gene specific PCR is a promising result in differentiating of enterotoxigenic B. cereus from non- enterotoxigenic ones. PCR is a good alternative for a RPLA and PCR is able to distinguish Enterotoxigenic B. cereus isolates from non Enterotoxigenic B. cereus in shorter time and with less cost.