Distribution of Macrolide-Lincosamide-Streptogramin B antibiotics resistance genes in clinical isolates of Staphylococci

Abstract Background Staphylococci are the most commonly isolated pathogen from clinical specimen. These isolates are posing threat due to increasing trend of antimicrobial resistance particularly methicillin. Macrolide-lincosamide streptogramin B family of antibiotics is commonly used to treat such infections. This study was aimed to detect the prevalence of inducible clindamycin resistance and observation of erm and msr genes among Staphylococci isolated from tertiary care hospital of Nepal.Methods Staphylococci from different clinical specimen were identified and antibiotic susceptibility profile were determined following Kirby Bauer disc diffusion method. The double disc diffusion or D-zone test as outlined in CLSI document M100-S24 was performed to examine inducible clindamycin resistance isolates. Multiplex PCR was performed for detection of erm and msr gene in isolates using specific primers for ermA , ermB, ermC, msrA and msrB genes.Results Of the 60 Staphylococci isolates, 39 (65%) were Staphylococcus aureus ( S. aureus ) and 21 (35%) were coagulase negative Staphylococci (CNS) with 25 (64%) and 15 (71%) representing methicillin resistant S. aureus and CNS respectively. Constitutive and inducible MLS B phenotype was observed among 24 (40%) and 14 (23%) isolates respectively by D test. The most prevalent resistant gene was ermC gene (37%) followed by msr B (12%), erm B (10%) and msr A (10%). None of the isolates were found to possess erm A gene.Conclusions The resistant genes were detected more among CNS than S. aureus. The presence of constitutive and inducible MLS B as well as resistant genes among Staphylococci necessitates detection of such isolates to minimize treatment failure. The presence of resistant characteristic varies with hospital settings, geographical locations, patients’ demography etc. The result from this study may help elucidate the predominant resistant characteristics in clinical Staphylococci isolated from tertiary care hospital of Nepal.