Isolation and molecular characterisation of atypical enterotoxigenic Bacillus cereus with negative Voges-Proskauer reaction from Indian white shrimp Fenneropenaeus indicus (H. Milne Edwards, 1837)

Abstract

Enterotoxigenic Bacillus cereus is one of the important pathogenic organisms, which causes two distinct type of food poisoning in human beings viz., emetic type and diarrhoeal type. As per biochemical tests, B. cereus is generally Voges-Proskauer (VP) positive. In the present study, two enterotoxigenic B. cereus isolates from white shrimp (Fenneropenaeus indicus) with negative VP reaction have been reported. Both the isolates were confirmed as B. cereus by other biochemical tests as well as molecular methods like PCR and 16S rRNA gene sequencing. They were also found to produce diarrhoeal enterotoxin by reverse passive latex agglutination (RPLA) test. The enterotoxin producing genes, hbla and entb were detected in both the isolates.