*1Hamza, J. A., 2Garba, L., 2Yarma, A. A., 2Ibrahim, H. I., and 1Adamu, H.
1Department of Pharmaceutical Microbiology and Biotechnology, Faculty of Pharmaceutical Sciences, Gombe State University, Gombe, Nigeria 2Department of Microbiology, Gombe State University, Gombe, Nigeria *Correspondence to: jabirgsu@gsu.edu.ng, Te: +2347039306208
Abstract:
Background: Vancomycin is an antibiotic of last resort for the treatment of multidrug resistant Staphylococcus aureus including methicillin resistant S. aureus (MRSA). The emergence of vancomycin resistant S. aureus (VRSA) is a major threat to global healthcare with devastating implications. In Nigeria, data on VRSA is scarce while the molecular characterization of the organism from Northeast region is nearly absent. This current is aim to detect vancomycin resistance among MRSA isolates from Gombe State, Nigeria, and identify the genetic determinants involved.
Methodology: This was a laboratory-based study of 70 confirmed S. aureus isolates which were screen for methicillin resistance using the modified Kirby-Bauer disc diffusion method. Vancomycin resistance screening was conducted using the E-Test Strip and micro broth dilution method according to CLSI guideline (MIC ≥16 μg/mL). Multiplex PCR was used to detect the presence of vanA and vanB genes in isolates that were phenotypically resistant to vancomycin.
Results: Out of the 70 isolates, 15 (21.4%) were methicillin resistant. Vancomycin resistance was observed in 5 (33.3%) and 3 (20.0%) of the MRSA isolates using E-test strip and micro broth dilution methods respectively. Molecular detection of vancomycin resistance gene(s) among the 5 VRSA isolates revealed 2 (40.0%) had the unusual dual carriage of van A and van B genes. No vancomycin intermediate resistance was detected. Conclusion: This study is among the earliest report from the northeastern part of Nigeria that investigated VRSA and to the best of our knowledge the first documented evidence of dual carriage of vanA and vanB in VRSA in the region. Thus; these findings highlight the need for urgent antimicrobial surveillance and effective infection control measures to tackle the dissemination of the highly resistant S. aureus strains.
Keywords: Staphylococcus aureus, MRSA, VRSA, Antimicrobial resistance
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