Clindamycin Resistance among Staphylococcus Aureus Isolated at Mbarara Regional Referral Hospital, in South Western Uganda
Bashir Mwambi *
Department of Microbiology, Mbarara University of Science and Technology, P.O.Box 1410 Mbarara, Uganda
Jacob Iramiot
Department of Microbiology, Mbarara University of Science and Technology, P.O.Box 1410 Mbarara, Uganda
Freddie Bwanga
Department of Medical Microbiology Makerere University College of Health Sciences P. O Box 7072 Kampala, Uganda and MBN Clinical Laboratories, Uganda
Marthae Nakaye
Department of Microbiology, Mbarara University of Science and Technology, P.O.Box 1410 Mbarara, Uganda
Herbert Itabangi
Department of Microbiology, Mbarara University of Science and Technology, P.O.Box 1410 Mbarara, Uganda
Joel Bazira
Department of Microbiology, Mbarara University of Science and Technology, P.O.Box 1410 Mbarara, Uganda
*Author to whom correspondence should be addressed.
Abstract
Aims: The study was conducted to determine the prevalence of Clindamycin (CL) resistance and antimicrobial susceptibility among clinical isolates of Staphylococcus aureus (S. aureus) from Mbarara Regional Referral Hospital (MRRH) in Southwestern Uganda.
Study Design: Laboratory based cross sectional study.
Place and Duration of the Study: The study was conducted at the Microbiology department of Mbarara Regional referral hospital between November 2012 and December 2013.
Methodology: In our study, we recruited 300 S. aureus isolates that were stored in the laboratory and were obtained from different clinical samples. The isolates were tested for antimicrobial susceptibility by phenotypic methods and for the genotypic expression of Macrolide Lincosamide StreptograminB (MLSB) resistance genes (ermA, ermB, ermC, and msrA). The D-test was also performed.
Results: Phenotypically, a total of 109 (36%) S. aureus isolates were resistant to CL, of which 9 (3%) were constitutively resistant while 100 (33.3%) were inducibly resistant. Genotypicaly, 134/300 (44.7%) isolates possessed at least one of the MLSB resistance genes. 23/300 (7.7%) tested positive for ermB, 98/300 (32.7%) tested positive for the ermC and 43/300 (14.3%) tested positive for the msrA genes with none possessing the ermA gene. Isolates were highly resistant to Sulfamethoxazole/trimethoprim, Erythromycin and Oxacillin with moderate resistance to Vancomycin and Imipenem and least resistance to Linezolid
Conclusion: S. aureus resistance to CL was high in this set up. There was also high resistance to Sulfamethoxazole/trimethoprim, Erythromycin and Oxacillin but low resistance to Linezolid.
Keywords: Staphylococcus aureus, clindamycin, phenotypic, genetic, resistance, d-test