Incidence of methicillin, inducible clindamycin, and vancomycin resistance in Staphylococcus aureus clinical isolates in Gombe, Northeastern Nigeria

Abstract

Introduction Antimicrobial resistance (AMR) has become a significant public health concern, jeopardizing the ability to effectively prevent and treat a growing number of infections caused by microorganisms that no longer respond to standard treatments. Despite the introduction of new antibiotics over the years, bacteria causing both common and severe infections have consistently developed resistance. In light of this escalating threat, urgent action is necessary to prevent a potential global healthcare crisis. This study aimed to determine the incidence of methicillin resistant and vancomycin resistant S. aureus clinical isolates from Federal Teaching Hospital and State Specialist Hospital Gombe, Nigeria. Methods A cross-sectional study was conducted from October 2021 to January 2022 in two hospitals within the city of Gombe. Antibiotic susceptibility testing was conducted via modify Kirby Bauer disc diffusion and the macro broth dilution method. The species-specific 16S rRNA gene was investigated in the presumptive identified S. aureus isolates whereas the mecA and vanA genes were investigated in cefoxitin and vancomycin resistant S. aureus isolates via PCR. SPSS version 21 was used to determine the statistical associations between the MRSA and MDR characteristics of the S. aureus isolates. Results A total of two hundred and eighty (280) suspected consecutive staphylococcal isolates were collected and thirty three (33) S. aureus isolates were confirmed by the presence of the 16S rRNA gene; 75.8 % were found to be multidrug-resistant (MDR) but one (1) isolate is susceptible,to all the tested antibiotics, 54.5 % were methicillin-resistant (MRSA) and 45 % were vancomycin resistant (VRSA). A statistically significant association (p-value˂0.05) was observed between MDR isolates and MRSA. A total of 54.6 % of the isolates were constitutive clindamycin resistant whereas 6.1 % were inducible clindamycin resistant. Among the isolates that are phenotypically resistant to methicillin and vancomycin, 20 % of the isolates harbor mecA and vanA but none harbor both genes. Conclusion This study highlights the incidence of MRSA and VRSA which poses a significant burden on healthcare systems.