Detection of enterotoxigenic methicillin resistant Staphylococcus aureus in dairy desserts by multiplex-PCR

Abstract EN

The aim of this study is to evaluate the occurrence of methicillin-resistant Staphylococcus aureus (MRSA) in dairy desserts samples and to investigate the antimicrobial resistance and molecular characteristics of these strains using PCR.

A total of 120 samples comprising sweetened whipped cream, mehallabeia, ice cream and rice with milk were randomly collected from confectioneries, dairy shops, primitive restaurants and supermarkets in Sohag city, Egypt (30 samples each) and examined for presence of S.

aureus.

The results revealed that S.

aureus could be detected in 23.3 % of sweetened whipped cream, 6.7 % of mehallabeia, 16.7 % of ice cream and 3.3 % of rice with milk samples.

The results of antibiogram testing revealed that the highest percentage 9 (7.5 %) of S.

aureus isolates showed a complete resistance and 4 (3.3 %) showed intermediate resistance.

However, the lowest percentage 2 (1.7 %) of the isolates were sensitive to methicillin.

Eight out of nine strains that showed complete resistance using antibiotic sensitivity test identified as MRSA by detection of mecA gene by PCR (five from sweetened whipped cream, one from mehallbeia and two from ice cream samples).

Furthermore, some classical enterotoxins gene profile of complete resistant strain were investigated by using M-PCR.

The enterotoxins were detected in four strains only, and three different toxinotypes were recorded.

The most frequent ones were “sea” gene, and followed by "sed & seb" from sweetened whipped cream and ice cream samples, while no "sec" gene could be detected from all samples.

It is emphasized that the presence of S.

aureus and their SEs genes in dairy desserts may be regarded as a potential risk for human health.