Pheno- and genotyping of Staphylococcus aureus isolates of sheep origin

Abstract

The aim of the study was to determine the prevalence of genes encoding virulence factors in Staphylococcus aureus strains isolated from raw sheep milk, sheep cheese and Bryndza cheese. Genes encoding staphylococcal enterotoxin (sea, seb, sec, sed and see), toxic shock syndrome toxin-1 (tst), exfoliative toxins (eta and etb) and collagen-binding protein (cna) were detected. In a total of 79 S. aureus isolates all assessed toxins encoding genes were found, except for see, eta and etb. Overall, 75.9% of S. aureus isolates were found to be positive for one or more toxin genes. The sec gene was found most frequently (24.1%), followed by tst (22.8%), seb (13.9%), sed (10.1%) and sea (5.1%). The cna gene was detected in 55.7% of S. aureus isolates. Based on tandem repeats in coa gene, five coa types were observed, further divided into 16 subtypes based on their RFLP pattern. Similarly tandem repeats in spa gene divided S. aureus isolates into 7 types. In the parallel antibiotic resistance study, 69.6% isolates were resistant to at least one of the 11 tested antibiotics. The pheno- and genotyping of S. aureus isolates of sheep origin presented in this work update the epidemiological data in Slovakia.