Objective: Staphylococcus aureus is one of the most significant pathogens causing significant morbidity and mortality. Moreover, the incidence of MLS S. aureus (resistant at least for one macrolide) infections continues to grow globally. The aim of this study is to examine the expression of resistance of S. aureus isolates to MLS and the prevalence of genes involved in this resistance using PCR.
Methods:A total 38 strains of S. aureus MLS-resistant were isolated in the Microbiology Labs at Nini Hospital in North Lebanon. The disk diffusion method was used to determine the phenotype of the MLS resistance. The resistance genes involved were detected by PCR using specific gene primers for ermA, ermB, ermC, msrA, linA, mefA, vat and vgb genes.Results: A total of 55.3% of the isolates were positive for inducible phenotype (iMLS B ), of these 15.8% were positive for the constitutive phenotype (cMLS B ), 23.7% for MS B phenotype and 5.2% for L phenotype. The ermC gene was the most prevalent (52.6%), while ermA, ermB, msrA and linA genes were observed with lower prevalence. A combination of several of these genes was detected,whereas the vgb, vat and mefA genes were not detected in any of the clinical isolates.
Conclusion:This study is the first investigated characterization of MLS resistance genes in clinical isolates of S. aureus in Lebanon according to