Antimicrobial resistance patterns of Staphylococcus aureus isolates in tertiary hospital in Somalia: a retrospective...

Staphylococcus aureus (S. aureus) is a commensal microorganism that is part of the normal human flora but has the potential to cause a wide range of infections, from superficial skin conditions to life-threatening systemic diseases such as bacteremia. The aim of this study was to evaluate the epidemiological characteristics and antimicrobial resistance patterns of S. aureus strains isolated between 2019 and 2024 at a tertiary hospital in Mogadishu, Somalia.

In this retrospective study, a total of 1,381 S. aureus isolates obtained from various clinical specimens submitted from different departments to the Medical Microbiology Laboratory were analyzed. The isolates were identified using standard microbiological methods, and antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method in accordance with Clinical and Laboratory Standards Institute (CLSI) criteria. Data were statistically analyzed, and a p-value of < 0.05 was considered statistically significant.

Of the 1,381 S. aureus isolates, 670 (48.51%) were identified as methicillin-resistant Staphylococcus aureus (MRSA), while 711 (51.49%) were methicillin-susceptible Staphylococcus aureus (MSSA). Of the isolates, 55.03% were obtained from male patients and 44.97% from female patients. The highest isolation rate was observed in the 18-64 year age group. Among clinical specimens, wound samples (47.57%) and blood cultures (37.14%) were the most common. Both MRSA and MSSA isolates were most frequently recovered from outpatient clinics, and a statistically significant difference was observed in distribution across clinical departments (p = 0.004). Antimicrobial susceptibility analysis revealed high resistance rates among MRSA isolates to penicillin G (98.61%), erythromycin (71.11%), and tetracycline (66%), while MSSA isolates showed high resistance to penicillin G (91.51%), tetracycline (53.57%), and levofloxacin (49.61%), while MSSA isolates showed high resistance to penicillin G (91.51%) and tetracycline (53.57%). Very low resistance rates were observed for linezolid, vancomycin, and quinupristin-dalfopristin.

S. aureus remains a significant pathogen in the region, particularly due to the high prevalence of MRSA strains. The elevated resistance rates identified in this study underscore the need to tailor empirical treatment strategies based on local antibiogram data. Continuous surveillance and effective antimicrobial stewardship programs are critical for controlling the emergence and spread of antimicrobial resistance.