A CROSS-SECTIONAL STUDY ON ANTIBIOTIC SUSCEPTIBILITY PROFILING OF STAPHYLOCOCCUS AUREUS FROM WOUND SWABS

Abstract

Background: Staphylococcus aureus (S. aureus) is a major cause of skin and soft tissue infections, and methicillin-resistant strains (MRSA) are very difficult to manage due to being multidrug-resistant, with very limited accepted treatment regimens. MRSA infections are associated with slow wound healing, extended hospital stay, increased health care spending, and morbidity. Despite the inconsistent prevalence reported in the global studies, the regional data concerning the MRSA burden, the risk factors, and the profile of resistance in wound infections are limited. The objective of this study was to determine the prevalence of MRSA in S. aureus isolates in wound swabs, clinical and demographic predictors, and antimicrobial susceptibility to inform empirical treatment.

Methods: The present cross-sectional observational study was carried out at the microbiology department of a hospital. Non-probability consecutive sampling was used to sample 250 wound swabs from inpatients and outpatients. Identification was performed using standard microbiological methods, including cefoxitin disc diffusion and mecA PCR confirmation of MRSA. Susceptibility to the antibiotics was determined based on Clinical and Laboratory Standards Institute (CLSI) guidelines. Clinical variables, including comorbidities, exposure to antibiotics, hospitalization, and type of wound, were noted. SPSS version 26.0 was used to analyze the data with chi-square, Fisher-Exact, and t-tests, and a p-value <0.05 was regarded statistically significant.

Results: Of 250 samples, 100 (40%) contained S. aureus, 45 (45%) of which were MRSA, and 55 (55%) were MSSA. MRSA was strongly related to diabetes (p = 0.008), past use of antibiotics (p = 0.002), hospitalization (p = 0.047), and surgical or traumatic wounds (p = 0.05). MRSA exhibited the greatest resistance to penicillin, 45 (100.0%), followed by erythromycin, 31 (68.9%), and ciprofloxacin, 24 (53.3%). Tetracycline, 18 (40.0%), and clindamycin, 9 (20.0%), were reported to have moderate resistance. MRSA was susceptible to vancomycin, 1 (2.2%), and linezolid, 1 (2.2%), with no statistical difference between MRSA and MSSA.

Conclusion: This single-center study demonstrated a significant burden of S. aureus in wound infections, with a high proportion of MRSA and the most common oral antibiotic resistance. However, vancomycin and linezolid were still effective. Empiric therapy should be guided by regular monitoring in the local area, tight infection control, and antimicrobial stewardship to reduce the development of additional resistance.