Molecular Epidemiological Characterization of Staphylococcus aureus and Staphylococcus argenteus Clinical Isolates from a National Tertiary Care Hospital in Myanmar: Co-Isolation of Multiple Clones and Identification of Novel Staphylocoagulase Genotype

Spread of antimicrobial resistance and virulence factors among Staphylococcus aureus/Staphylococcus argenteus poses a potential public health concern in Myanmar. In this study, a total of 226 clinical isolates of S. aureus (n = 211) and S. argenteus (n = 15) collected in Yangon General Hospital during a two-year period were analyzed for their antimicrobial susceptibility and genetic features. Methicillin-resistant S. aureus (MRSA) accounted for 19% of S. aureus isolates, associated with mostly staphylococcal cassette chromosome mec (SCCmec) type IV, or V. Panton-Valentine leukocidin (PVL) genes were detected in methicillin-susceptible S. aureus (MSSA) at significantly higher rate (39%) than in MRSA (22%). Among MRSA, ST361 (clonal complex [CC] 361), ST772 (CC1), and ST239 (CC8) were frequently identified, while the most common clone in MSSA was ST2990 (CC1), followed by ST121 and CC8 comprising five STs. Novel coagulase gene genotype XVI was identified in four MSSA isolates. All the S. argenteus isolates were assigned to ST2250 and mecA negative, including only one PVL-positive isolate. MSSA and S. argenteus were co-isolated from two patients, while two different MSSA clones were simultaneously identified in eight patients. This study revealed clonal diversity and genetic characteristics of current MRSA/MSSA/S. argenteus clinical isolates in the national tertiary care hospital in Myanmar.