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 LAMPand PCRwere 100 fg/test and 10 pg/test, respectively. In all
cases,LAMP was found to be 100-fold more sensitive than PCR.NoDNA 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,LAMPhas been proven to
be a powerful tool, which is useful for detection and obtaining a reliable identification
of the toxin genes of the pathogen fromdiverse food sources.