Drug Resistance Genes and Source of Methicillin Resistant <i>Staphylococcus </i><i>aureus</i> Strains amongst HIV Patients in Fako Division of Cameroon: A Case-Control Study

Background: Methicillin Resistant Staphylococcus aureus and severe antimicrobial resistance is worsened in HIV positive patients, driven by the presence of drug resistance traits. This study aimed to determine the prevalence of MRSA, antibiotic susceptibility, source of infection and the distribution of drug resistance genes amongst HIV positive and HIV negative participants in Fako-Cameroon. Methods: Urine and nasal samples were cultured on CLED and MSA agar respectively following standard procedures. The clinical isolates were characterized biochemically and comfirmed by nuc gene detection of S. aureus. Antimicrobial susceptibility with selected locally prescribed antibiotics was done using the Kirby Bauer disc diffusion technique. Drug resistance genes (vanA, mecA, ermA, sul3 and ermC) were determined using PCR amplification. Data was analyzed using Microsoft Excel 2016 and SPSS version 25; Chi square was set at P ≤ 0.05. Results: The overall prevalence of MRSA was 28.8%. MRSA was higher (P = 0.0001) in HIV positive patients (19.4%) than in HIV negative individuals (9.4%). Amongst HIV positive and HIV negative participants, high sensitivity of urogenital S. aureus was observed amongst Aminoglycosides [Amikacin (26.3% vs 52.9%)] and Nitrofurans [Nitrofurantoin (25.2% vs 53.1%)]. Resistance was seen against Ciprofloxacin [39.5% vs 41.2%] in HIV positive and HIV negative participants respectively. MAR index of urogenital S. aureus was higher amongst HIV positive patients (0.9) compared to HIV negative individuals (0.7). Majority (38.0%) of S. aureus clinical isolates cultured from the urine of HIV positive patients were not identical to isolates from the nostrils of the same patients. The overall detection rate of drug resistance genes were distributed as follows; vanA (30.8%), ermA (29.6%), mecA (28.6%), sul3 (21.6%) and ermC (18.0%). Conclusion: Methicillin resistant Staphylococcus aureus is more common amongst HIV positive patients, with the clinical isolates being, more resistant to commonly prescribed antimicrobial agents. The clinical isolates causing urinary tract infections in HIV positive patients are usually not from the normal flora (the nostrils).