DETECTION OF ENTEROTOXIGENIC STAPHYLOCOCCI BY LOOP-MEDIATED ISOTHERMAL AMPLIFICATION METHOD

Enterotoxigenic staphylococcal strains isolated from the food samples in Mysore, Karnataka, India, were evaluated using loop-mediated isothermal amplification (LAMP) method. The detection limit was 100 colony-forming units (cfu)/test for LAMP and 10,000 cfu/test for PCR. In the presence of coexisting microbes such as Yersinia enterocolitica, the assays were carried out and the quantified DNA was subjected to LAMP and polymerase chain reaction (PCR) analysis. Despite the presence of Y. enterocolitica genomic DNA, the sensitivity of LAMP remains the same. The detection limits of LAMP and PCR were 100 fg/test and 10 pg/test, respectively. In all cases, LAMP was found to be 100-fold more sensitive than PCR. No DNA amplification was observed for ent A, ent B, ent C and ent D non-producing staphylococci and other bacterial strains, indicating its high specificity. Thus, LAMP has been proven to be a powerful tool, which is useful for detection and obtaining a reliable identification of the toxin genes of the pathogen from diverse food sources.