Methicillin-resistant Staphylococcus aureus (MRSA) in Wasit Province, Iraq: A prevalence of molecular epidemiology, and preserved vancomycin and tigecycline susceptibility

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a paradigmatic example of antimicrobial resistance (AMR) and a leading cause of both healthcare-associated (HA-MRSA) and community-associated (CA-MRSA) infections globally. In resource-limited settings like Iraq, overcrowded healthcare facilities, inconsistent infection prevention and control (IPC), and widespread empirical antibiotic use have created a permissive environment for multidrug-resistant pathogens. Despite the growing threat, epidemiological data from peripheral provinces such as Wasit remain fragmentary. Objective: This study aimed to determine the prevalence, molecular epidemiology, antimicrobial resistance patterns, and risk factors associated with S. aureus and MRSA among inpatients in Wasit Province, Iraq, from 2023 to 2024. Methods: A cross-sectional study was conducted across three tertiary hospitals: Wasit Teaching Hospital, Al-Zahra General Hospital, and Al-Batool Maternity and Pediatric Hospital. A total of 450 clinical specimens (blood, urine, wound exudates, CSF) were collected. Isolates were identified using conventional microbiological methods and confirmed by PCR targeting the nuc gene (S. aureus) and mecA gene (MRSA). Antimicrobial susceptibility testing was performed via Kirby-Bauer disk diffusion (CLSI 2023 guidelines). Statistical analysis was conducted using SPSS v26. Results: S. aureus was isolated from 102/450 specimens (28.7%), with the highest rate in wound exudates (38.7%). Of these, 45 (44.1%) were confirmed as MRSA by mecA detection. Resistance to penicillin (94.1%) and amoxicillin (90.2%) was nearly universal. High resistance was also observed for erythromycin (76.5%), ciprofloxacin (66.7%), and gentamicin (51.0%). In contrast, vancomycin and tigecycline showed high susceptibility (98.0% and 99.0%, respectively). Multivariate analysis revealed that prolonged hospitalization (>7 days), prior broad-spectrum antibiotic use, major surgery, and central venous catheterization were significantly associated with MRSA (p < 0.05). Conclusion: This study documents a high burden of MRSA in Wasit Province, reflecting a critical AMR crisis in Iraq. Sustained susceptibility to vancomycin and tigecycline offers a therapeutic window, but underscores the urgent need for antimicrobial stewardship and enhanced infection control. These findings support the integration of molecular diagnostics and the establishment of a regional AMR surveillance network.