Detection of coding genes for enterotoxins in Bacillus cereus by PCR and their products by BCET-RPLA and ELISA Assay

Determination of enterotoxin production, diarrhoeal and emetic gene identification was studied in 41 Bacillus cereus strains isolated from raw cows' and raw goats' milk, pasteurized milk, dairy products during technological processing and from dairy plant equipment. Presence of enterotoxins was detected by BCET-RPLA (HBL) and ELISA immunoassay (NHE). Gene identification (nheA, nheB, nheC, hblA, hblC, hblD, bceT, cytK-1, cytK-2, entFM and ces) was achieved by means of PCR. Enterotoxin HBL was detected in 32 strains, enterotoxin NHE in all 41 strains. Presence of all three genes nheA, nheB and nheC was confirmed in 40 strains and genes hblA, hblC and hblD in 29 strains. The comparison of the methods used led to the following results: 1) BCET-RPLA (which detects L2 component) and PCR (positive or negative all three hblA, hblC and hblD gene detection) were identical in 73% of the cases; 2) ELISA (NheA) and PCR (all three nheC, nheB and nheA gene expression) were identical in 98% of the cases.