Trends in Antimicrobial Resistance of Staphylococcus aureus Isolated from Clinical Samples at Mbarara Regional Referral Hospital in Rural Uganda

Aim: This study aimed at describing the antibiotic susceptibility patterns of S. aureus isolated from clinical samples at Mbarara Regional Referral Hospital from 2003 to 2012.

Methods: This was a retrospective study that included clinical specimens cultured at the Microbiology laboratory of Mbarara Regional referral hospital between 2003 and 2012. Cultures and sensitivity data were abstracted from the laboratory registers using a data abstraction form. Among the positive culture reports, the antibiotic sensitivity of the common bacteria isolated were also recorded. Analysis of susceptibility data was limited to Staphylococcus aureus, the commonest organism identified. The data were entered into Epi info and exported to Stata Version 12.1 for analysis.

Results: A total of 36,080 cultures were performed over a period of 10 years. Of these 7,744 (21.5%) specimens grew an organism. S. aureus was the most prevalent organism isolated. Fifty nine percent of the S. aureus was isolated from blood samples followed by 22% from pus samples, urine (8%) and HVS (5%). During the study period, resistance of S.aureus to chloramphenicol, amoxycillin, penicillin, tetracycline, and cotrimoxazole ranged from 50-90% while S. aureus resistance to Gentamicin and ceftriaxone ranged from 10-20%.

Conclusion: Over the last decade, S. aureus isolates showed up to 90% resistance to commonly prescribed oral antibiotics. We recommend regular review of antibiotic resistance patterns to inform hospitals’ on guidelines on empirical antibiotic prescription, especially in resource-limited settings where susceptibility testing may not be feasible.