Characterization of staphylococcus aureus from community and hospital settings in Uganda

Abstract

Community and hospital acquired infections have become prevalent in Uganda with Staphylococcus aureus documented as the leading causative agent. The emergence of methicillin resistant S.aureus (MRSA) has complicated treatment of S.aureus infections since the majority of MRSA strains are resistant to multiple antibiotics including beta-lactams, aminoglycosides, macrolides, lincosamides and more recently floroquinolones. MRSA accounts for 37.5% of S.aureus isolated in clinical isolates at Mulago hospital and 33.6% of S. aureus isolated in the community in Uganda. MRSA surveillance studies in Europe and North America have revealed differences in strains causing community and hospital infections; however there has been no study on this topic in Uganda. This study therefore aimed at determining the genotypes of S.aureus circulating in community settings in Uganda, in comparison with those previously detected in the hospital. Results: Six hundred community samples were studied, of which 116 (19.3%) grew S.aureus. Thirty nine isolates were methicillin resistant, implying that MRSA prevalence in the community was 6.5% (39/600) at population level and 33.6% (39/116) among S.aureus isolates grown. For previously characterized hospital isolates in Mulago MRSA prevalence was at 37.5%. The predominant SCCmec genotypes in the community were type IV at 30.7% (12/39) and type I at 23.1% (9/39). Types III, II and V were less prevalent at 5.1% (2/39), 2.5% (1/39), and 2.5% (1/39), respectively. SCCmec genotype V was the most predominant (33.3%) followed by SCCmec I at in previously characterised S.aureus isolates from Mulago hospitals, There were statistically significant differences between SCCmec type IV and V among community isolates and previously characterised hospital isolates, implying different genotypes are circulating in both settings.20 community MRSA isolates have been sequenced and one spa Type t1456 was identified, while the rest had no hits in the database and were considered novel strains. Conclusion: The MRSA prevalence in the community and hospital settings in Uganda is comparable. However, the pvl gene was more prevalent in the hospital isolates than in the community isolates. The finding of hospital associated MRSA genotypes in the community shows no difference by SCCmec typing in genotypes among community and hospital MRSA in Uganda; this has significant implications regarding the epidemiology of MRSA in this country. Of concern was the detection of spa Type t1456, which is globally associated with community and livestock infections. This is the first study to characterize MRSA from the community in Uganda.