Prevalence and associated factors of methicillin-resistant and vancomycin-susceptible Staphylococcus aureus among clinical isolates at Hawassa university comprehensive specialized hospital, Ethiopia, 2019-2023.

BACKGROUND: Staphylococcus aureus (S. aureus) has become a major public health concern due to its increasing resistance to antibiotics. Methicillin and vancomycin-resistant S. aureus strains are considered as high-priority pathogens contributing to increased morbidity and mortality worldwide. There is limited data on the prevalence and trends of methicillin and vancomycin resistant S. aureus among clinical isolates in Hawassa, Ethiopia. OBJECTIVE: This study aimed to determine the prevalence, temporal trends, antibiotic resistance patterns, and associated factors of Methicillin-Resistant S. aureus (MRSA) and Vancomycin-Resistant S. aureus (VRSA) among patients admitted to Hawassa University Comprehensive Specialized Hospital (HUCSH) Hawassa, Ethiopia. METHODS: A hospital-based retrospective cross-sectional study was conducted from April 20 to June 27, 2024, involving patients diagnosed with S. aureus infections at HUCSH between 2019 and 2023. Stored S. aureus isolates were re-cultured and identified using standard biochemical tests. Antibiotic susceptibility testing (AST) was performed using the disc diffusion method for cefoxitin and other antibiotics, and the Epsilometer test (E-test) for vancomycin. Socio-demographic and clinical data were extracted from the bacteriology culture registration book and medical records using a structured data collection format. Data were analyzed using SPSS version 23. Bivariate and multivariable logistic regressions were performed to identify predictors of MRSA infection, with p < 0.05 considered statistically significant. RESULTS: Of the 151 S. aureus isolates recovered, 17.9% (27/151), (95% CI: 11.9%-23.8%) were MRSA. The MRSA was most frequently isolated from abscesses (40.7%) followed by blood (29.6%) and other specimens (14.8%). All isolates were susceptible to vancomycin (MIC ≤ 2 µg/mL), with no VRSA detected. Multidrug resistance (MDR) was observed in 15.9% (24/151) of isolates. Resistance to clindamycin, erythromycin, and penicillin was 19.9%, 26.5%, and 89.4%, respectively. The highest MRSA prevalence was recorded in 2023 (n = 6; 26.1%), and the lowest in 2021 (n = 3; 8.8%). Patients admitted to the surgical ward had significantly higher odds of MRSA infection compared to the other wards (AOR: 6.55; 95% CI: 1.52%-28.13%; p = 0.01). There is a significantly higher prevalence of MRSA infections (AOR = 2.19; 95% CI: 1.103-2.974) among female patients as compared to male patients. CONCLUSION: The MRSA prevalence observed aligns with other studies conducted in Ethiopia. Temporal variations in MRSA prevalence underscore the need for continuous surveillance to identify contributing factors and inform targeted infection control strategies aimed at mitigating the spread of resistant S. aureus strains. There is a significant association between MRSA occurrence and admission to the surgical ward, highlighting the need for targeted infection prevention and control strategies in high-risk hospital wards. Unlike other studies, a higher prevalence of MRSA was observed among female patients, warranting further investigation to identify potential underlying factors.