Prevalence and Anti-Microbial Susceptibility of Methicillin Resistant Staphylococcus aureus at Moi Teaching and Referral Hospital Eldoret

Background: Methicillin-resistant Staphylococcus aureus (MRSA) are pathogens that have major negative impact in all aspects of patient care and are increasingly being recognized as troublesome pathogens in the community. The MRSA are multi-drug resistant bacteria responsible for higher morbidity, mortality and cost of treatment in the affected patients. Research on MRSA antimicrobial susceptibility and resistance in developing countries is limited; hence accurate burden is not certain. Objective: To determine the prevalence and susceptibility pattern of MRSA in S. aureus isolates from patients treated in various units at Moi Teaching and Referral Hospital. Study Design: Cross-sectional design was used to conduct the study. Methods and Materials: Staphylococcus aureus stored isolates from patients at various units at Moi Teaching and Referral Hospital (MTRH) were identified by laboratory conventional methods. Methicillin resistant Staphylococcus aureus was determined using cefoxitin and oxacillin, discs and confirmed by Penicillin Binding Protein (PBP2a’) latex agglutination test. Susceptibility testing was performed according to the Clinical Laboratory Standards Institute procedures. Control strains used were: ATCC 43300 for Methicillin resistant S. aureus (MRSA) strains and ATCC 29213 for methicillin susceptible S. aureus (MSSA) strains. Nine anti-microbials (Erythromycin, Gentamycin, Tetracycline, Vancomycin, Rifampin, Linezolid, Ciprofloxacin, Clindamycin and Fucidicacid) were used to test the anti-microbial susceptibility patterns. Control organisms were run along with the isolates for quality Assurance. The data was analyzed using STATA version 11. Categorical variables were summarized as frequencies and the corresponding percentages. Results were presented using tables and graphs. Results: A total of 107 isolates of S. aureus were obtained, of which 39 (37%) were MRSA. Most of the MRSA, 13 (33%) and 7 (17%), were found in pus and tracheal aspirate samples respectively. Majority of the MRSA isolates were from surgical wards and intensive care unit. The MRSA isolates were highly resistant to erythromycin (92%; 36/39) and tetracycline (92% 36/39) and moderately susceptible to linezolid (77% 30/39), Vancomycin (75% 29/39) and fucidic acid (67% 26/39). A total of 28 (74.4%) MRSA isolates were Clindamycin inducible resistant. Conclusions and Recommendations: This study showed that MRSA is a significant pathogen at MTRH. The MRSA were most detected in pus specimens and least in peritoneal aspirates.