Investigation of toxin genes in Staphylococcus aureus strains isolated in Mustafa Kemal University Hospital

Authors: CEMİL DEMİR, ÖZKAN ASLANTAŞ, NİZAMİ DURAN, SABAHATTİN OCAK, BURÇİN ÖZER

Abstract: The aim of this study was to investigate the presence of genes encoding staphylococcal enterotoxins (SEs), exfoliative toxins (ETAs, ETBs), and toxic shock syndrome toxin-1 (TSST-1) by polymerase chain reaction (PCR) in Staphylococcus aureus strains isolated from various clinical samples from the Mustafa Kemal University Hospital. In addition, PCR-based restriction fragment length polymorphism (RFLP) analysis of the coa gene was employed to genotype the isolates. Materials and methods: A total of 120 S. aureus strains isolated from various clinical samples (blood, wounds, urine, conjuctival swabs, and tracheal aspirate) over a 1 year period, 2007-2008, were used in this study. Results: Almost 65.8% of the isolates possessed at least one toxin gene. The genes most frequently found were seg-sei (40.8%), followed by sea (30%) and eta (19.2%). Overall, 35 toxin genotypes were observed, among which the genotypes seg-sei, sea-seg-sei, and sea-see predominated at the rate of 8.3%, 5.8%, and 5%, respectively. Four coagulase genotype patterns were observed, with molecular sizes ranging from 570 to 970 bp. Coa-based RFLP analysis revealed 7 different patterns using AluI. Conclusion: Our results have revealed that toxin genes were very prevalent among S. aureus isolates, and the toxigenic isolates were independent of the genotypes obtained by PCR-RFLP of the coa gene (P > 0.05).

Keywords: Staphylococcus aureus, toxin genes, PCR-RFLP, coagulase

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