Detection of Toxigenic Staphylococcus aureus and Escherichia coli Serotypes in Egyptian Cheeses by Multiplex PCR

Abstract

From white soft cheese, 150 samples were gathered from various regions in Kafrelsheikh, Egypt. Samples represented as Kariesh, Damietta and feta cheese (50 each). Microbiological analysis to detect Escherichia coli and staphylococcus aureus. The isolated S. aureus samples were tested biochemically then examined for the existence of genes of staphylococcal enterotoxins (SE) by multiplex PCR. Biochemical identification of E. coli and serological detection of enteropathogenic types were done. Molecular diagnosis was performed to identify Shiga toxin (Stx1), Shiga toxin (Stx2) and intimin (eaeA) genes of enteropathogenic E. coli. Results declared that S. aureus was found in 62% of Kariesh, 38% of Damietta and 28% of feta cheese samples. Results of PCR displayed that 33.3 % of the isolated S. aureus had SEA gene, 3.33% had SEB gene, 3.33% had SEC gene, 6.67% had SED gene, 3.33% had SEC & SED genes and 3.33% possessed SEA, SEB and SEC genes. E. coli was found in 26% of Kariesh samples while Damietta and feta cheese samples revealed same occurrence (4%). Ten various serotypes of E. coli were characterized as following O26:H11(2.7%), O128:H2(2%), O111:H2 (1.3%), O124 serotype (1.3%), O91:H21(0.6%), O119:H6 (0.6%), O125:H21 (0.6%), O44:H18 (0.6%), O121:H7(0.6%) and O86 (0.6%). Regarding PCR results for E. coli, 23.5% of the detected serotypes carried stx1, stx2 and eaeA genes, 14.3% carried stx2 and eaeA genes, 13.1% carried stx1 plus stx2 genes, 23.5% had stx1 gene only and 17.6% possessed stx2 gene only. These results concluded that white soft cheese may represent a transmission vehicle for critical pathogens.