Genetic characterization of methicillin-resistant / susceptible (MRSA/MSSA) and clinical isolates in Bangladesh: Dominance of ST6-MRSA-IV/t304 and detection of / in ST8-MSSA/t008.

Objectives: Coagulase-positive staphylococcus (CoPS), represented by , is a major cause of infections in humans. This study aimed to investigate molecular epidemiological characteristics, antimicrobial resistance, and their trends of CoPS in Bangladesh.

Methods: Clinical isolates of CoPS were collected from two medical institutions in Bangladesh for a 2-year period and analyzed for their species, genotypes, virulence factors, antimicrobial susceptibility, and resistance determinants.

Results: 172 CoPS isolates collected were identified as or (170 and two, respectively). Methicillin-resistant (MRSA) accounted for 36% (n = 61), having Staphylococcal cassette chromosome (SCC)-IV (82%) or V (18%). Panton-Valentine leukocidin (PVL) genes were detected at higher rate in methicillin-susceptible (MSSA) (62%) than MRSA (26%). MRSA comprised 11 STs, including a dominant type ST6 (46%) associated with mostly SCCIVa/-t304, and one isolate had genetic features of the USA300 clone (ST8/SCC-IVa/-IIIa/-t008/ACME-I/ΦSa2USA). STs of CC1, CC88, and CC398 were common in MSSA, with CC88 showing the highest PVL-positive rate. One MSSA isolate (ST8/-t008) harbored and showing susceptibility to linezolid. was methicillin-susceptible and belonged to ST2250/-XId.

Conclusions: Genetic characteristics of current MRSA/MSSA in Bangladesh were revealed, with first identification of at low prevalence.