Abstract:
OBJECTIVES: Staphylococcus aureus is one of the most common pathogens attributed to hospital infections. Although S. aureus
infections have been well studied in developed countries, far less is known about the biology of the pathogen in sub-Saharan
Africa.
METHODS: Here, we report on the isolation, antibiotic resistance profiling, whole genome sequencing, and genome comparison
of six multi-drug resistant isolates of S. aureus obtained from a referral hospital in Kakamega, Western Kenya.
RESULTS: Five of the six isolates contained a 20.7 kb circular plasmid carrying blaZ (associated with resistance to β-lactam
antibiotics). These five strains all belonged to the same sequence type, ST152. Despite the similarity of the plasmid in these isolates, whole genome sequencing revealed that the strains differed, depending on whether they were associated with hospitalacquired or community-acquired infections.
CONCLUSION: The intriguing finding is that the hospital-acquired and the community-acquired isolates of S. aureus belonging to the same genotype, ST152, formed two separate sub-clusters in the phylogenetic tree and differed by the repertoire
of accessory virulence genes. These data suggest ongoing adaptive evolution and significant genomic plasticity
