Molecular Detection of Macrolide-Induced Clindamycin Resistance Among Clinical Isolates of Staphylococcus aureus from Selected Hospitals in Katsina Metropolis

Abstract

Study’s Novelty/Excerpt This study investigates the prevalence and characteristics of inducible clindamycin resistance in Staphylococcus aureus isolates from clinical specimens in Katsina Metropolis, Nigeria, highlighting its significant clinical challenge. Antibiogram profiling revealed high efficacy rates for chloramphenicol (87.8%), clindamycin (79.6%), tetracycline (69.4%), and azithromycin (67.3%), while cefoxitin, ciprofloxacin, and trimethoprim-sulfamethoxazole showed the highest resistance levels. The D-test identified the Macrolide Lincosamide Streptogramin B (MLSB) phenotypes, with the ermC gene predominant among D-test-positive isolates expressing the inducible MLSB (iMLSB) phenotype, underscoring the need for targeted treatment strategies and continuous surveillance to manage antimicrobial resistance in this region. Full Abstract The emergence of inducible clindamycin resistance presents a significant challenge in treating Staphylococcus aureus (S. aureus) infections. This phenotype, evading routine susceptibility testing, compromises treatment efficacy and prolongs patient illness. Despite its clinical importance, limited data exist on its prevalence in Katsina Metropolis, Nigeria. This study aims to assess its prevalence and evaluate the phenotypic and genotypic characteristics among clinical isolates collected from selected hospitals in Katsina Metropolis. S. aureus isolates from various clinical specimens were obtained from three hospitals and identified using standard bacteriological methods. Antibiogram profiles were determined following CLSI guidelines, revealing varying efficacy among commonly prescribed antibiotics. Notably, chloramphenicol (87.8%), clindamycin (79.6%), tetracycline (69.4%), and azithromycin (67.3%) demonstrated high efficacy rates, while cefoxitin, ciprofloxacin, and trimethoprim-sulfamethoxazole exhibited the highest resistance level of (44.9%), (42.9%), and (40.8%) respectively. Prevalence of Macrolide Lincosamide Streptogramin B (MLSB) phenotypes was assessed using the D-test, unveiling specific resistance phenotypes among the isolates. Polymerase chain reaction detected the ermC gene as predominant among D-test-positive isolates, all expressing the iMLSB phenotype. These findings shed light on the prevalence and mechanisms of inducible clindamycin resistance in S. aureus clinical isolates in Katsina Metropolis, emphasizing the importance of tailored treatment strategies and ongoing surveillance in combating antimicrobial resistance effectively