Diversity of SCCmec Elements in Methicillin-Resistant Staphylococcus Aureus (MRSA) Recovered from a Healthy Student Population in Kenya

Abstract Background: Methicillin-resistant S. aureus continues to be a concern for public health systems, particularly due to infections emerging in non-hospital settings. Resistance to methicillin is presently classified as a serious phenomenon because the majority of methicillin-resistant strains are also multi-drug resistant. The genetic determinant of resistance to methicillin and other β-lactam antibiotics is the mec-A gene, which lies in the SCC mec resistance island. In Kenya, studies done previously have shown the existence of SCC mec types in clinical isolates, but similar information on isolates recovered from healthy populations is scanty. Methods: A cross-sectional study was conducted on healthy university students residing within the university residence halls to determine the carriage of MRSA. MRSA was detected using Cefoxitin (30µg), and mec-A gene and Sccmec elements were detected using conventional PCR methods. A total of 237 students were recruited, and 657 swabs were collected using standards methods for recovering S. aureus. Results: A total of 231 S. aureus isolates were recovered, out of which 26 (11.3%) were MRSA. Out of the 26 MRSA strains, 17 carried the mecA gene in their gene cassettes. SCC mec V was the most prevalent (61.5%), followed by SCC mec II (53.9%) among the MRSA strains. SCC mec IVa, SCCmec IVb, SCCmec IVc and SCC mec IVd were absent in all the isolates. SCC mec V was found to be highly prevalent (64.7%) followed by SCC mec II, 8 (47.1%) among the mecA -positive MRSA strains. On the other hand, small proportions of mecA- negative isolates harbored SCC mec I (0.9%), SCC mec II (3.3%), SCC mec III (0.5%) and SCC mec V (2.3%). Conclusion: This study revealed that the strains recovered from the student population were highly diverse in terms of the SCC mec elements they carried in their gene cassettes.