Invastigation of 16S rRNA, mecA and nuc genes in coagulase-positive and negative Staphylococci by Real-Time PCR

Abstract

Staphylococcus aureus is a Gram-positive, round-shaped bacterium that is a member of the Firmicutes. It is often positive for catalase and nitrate reduction. Pathogenic strains often promote infections by producing virulence factors such as potent protein toxins, and the expression of a cell-surface protein that binds and inactivates antibodies. Sepsis-related to methicillin-resistant S. aureus (MRSA) has significant morbidity and high mortality rates (15-30%). The methicillin resistance for S. aureus is coded with the mecA gene, while the methicillin sensitivity is coded with the nuc gene, and they are chromosomal. Similarly, it is coded with the coagulase gene for S. aureus (Coa). In this study, the 16S rRNA gene identification by Real-Time PCR was investigated in forty S. aureus isolates, which were cultured at different times in terms of MIC and SIR tests. The isolates used in the study were determined at the gene level in terms of their differences in methicillin resistance gene (MecA), methicillin susceptibility gene (Nuc), coagulase gene (Coa) and in terms of intra-species differences were examined. As a result of the study, Staphylococcus spp. yielded positive results with 16S rRNA gene-specific primers in all isolates. Real-Time PCR analysis of the isolates with SYBRGreen-based PCR analysis was performed with 16S rRNA gene-specific primers, and the samples were confirmed to be Staphylococcus. Analysis at the family level was followed by Coa, Nuc, and MecA gene Real-Time PCR results, and it was found that, in terms of Coa and Nuc genes, 19 isolates were positive and 21 isolates were negative. In terms of MecA gene, 16 isolates were positive according to the positive sigmoidal curves and to the single peak melting values, whereas 24 isolates were found to be negative. It was thought that this study will benefit the community by contributing to the rapid and effective diagnosis and treatment of infections caused by coagulase positive and negative Staphylococci.

Keywords

• Coagulaz gene
• MecA gene
• Nuc gene
• Staphylococcus aureus
• 16S rRNA gene

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