Molecular Identification of Vancomycin-Resistant Staphylococcus aureus Isolated from Wound Infections of Patients Attending Government Hospitals in Kaduna Metropolis

Abstract

Vancomycin-resistant S. aureus (VRSA) isolates are widely spread in both communities and hospitals, causing high morbidity and mortality worldwide. The present study aimed to identify vancomycin-resistant Staphylococcus aureus (VRSA) isolated from wound infections of patients attending Government hospitals in Kaduna Metropolis. A total of 168 wound samples were collected from patients across three selected hospitals. Staphyloccus aureus was isolated from wounds swaps and subjected to antibiotic susceptible testing using agar disk diffusion method. The VRSA isolates were detected by a combination of phenotypic and genotypic methods. Seven coagulase-positive S. aureus strains were isolated, which occurred higher among patients from YDMH (50%) compared to 31.25% among patients from RGH and 18.75% in GAGH. Wounds of male patients had higher infection with S. aureus (68.75%) than those of females (31.25); whereas those between 20-50 years old had the highest wound infection (50.00%). The isolates exhibited high resistance against vancomycin (71.42%). Seven isolates (43.75%) were categorized as VRSA.  Moreover, the MIC of the seven VRSA isolates were 8 μg/mL), with MBC ranging between 8-32 μg/mL with CFU ranging from 2.9-7.2×106, 1.7-3.7 ×106 and 1.7×106 CFU/mL respectively.  The isolates housed vanA and vanB gene (474bp and 800bp respectively). Given the alarming rate of resistance among VRSA isolates, monitoring of antibiotic resistance should be performed. Although vancomycin remains a drug of choice for VRSA, our study suggests that its efficacy may be limited due to development of resistance.