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Staphylococcal accessory gene regulator ( sar ) as a signature gene to detect enterotoxigenic staphylococci
Author(s) -
Padmapriya B.P.,
Ramesh A.,
Chandrashekar A.,
Varadaraj M.C.
Publication year - 2003
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2003.02069.x
Subject(s) - library science , food microbiology , medicine , microbiology and biotechnology , biology , genetics , computer science , bacteria
Aims: To evaluate the use of a staphylococcal accessory gene regulator ( sar ) as a means of detecting enterotoxigenic staphylococci. Methods and Results: Sar A gene‐specific primers were designed and applied in PCR, which resulted in the detection of 49 sar ‐positive isolates from a total of 67 natural food isolates of staphylococci. Colony hybridization using PCR‐generated Digoxigenin (DIG)‐labelled sar A probe tested in spiked samples of khoa (a traditional heat‐concentrated milk product) comprising a mixed microflora ensured the specificity of the probe. Validation experiments with the commercial samples of khoa also demonstrated the specificity of the probe. PCR characterization for enterotoxins A–D revealed the presence of atleast one of the toxin‐encoding genes in all the sar A‐positive isolates tested. Conclusion: The study indicated that sar A gene could be an ideal marker gene either in colony hybridization or in PCR, for an effective detection of potentially enterotoxigenic strains of staphylococci in a food system. Significance and Impact of the Study: As an alternative to targeting the individual toxin genes, a regulatory gene responsible for controlling the synthesis of various virulence factors may be a suitable target gene for screening potentially toxigenic staphylococci in food system using nucleic acid‐based methods.