Genotypes of methicillin-resistant Staphylococcus aureus isolated from neonates: the same genotypes of well-known CA-MRSA strains

Abstract number: 1134_02_211

Ko K.S., Park S., Kim S., Oh W.S., Song J.-H., Peck K.R.

Objective:

To investigate the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from neonates transferred from primary care obstetric clinics.

Methods:

Twelve MRSA strains were isolated from 11 neonates in 2004. Ten MRSA strains were also isolated from nurses and facilities in corresponding primary care obstetric clinics. Molecular features of MRSA strains were analysed by using multilocus sequence typing (MLST, arcC-aroE-glpF-gmk-pta-tpi-yqiL), spa typing, and SCCmec typing. Presence of Panton-Valentine leukocidin (PVL) gene was investigated by PCR method.

Results:

All 22 MRSA strains analysed in this study contained SCCmec type IVA. Of six isolates from neonates of clinic A, five showed ST1 (1–1–1–1–1–1–1) and resistance to only gentamicin and tetracycline. The remaining one showed novel ST (25–1–1–1–1–1–1), shared with one isolate from nurse of clinic A. Four MRSA strains from neonates of clinic B showed ST1 (1–1–1–1–1–1–1) and resistance to erythromycin and gentamicin, which is the same characteristics with three isolates from nurses and environment of clinic B. The other two MRSA strains from neonates of clinic B showed ST493 (62–1–1–1–1–1–1), which is shared by six strains from nurses and environment of clinic B. spa type of these 22 MRSA strains was identical as UJEBKBP and all strains were negative for PVL gene.

Conclusion:

MRSA strains isolated from neonates, hospital workers, and environment of the same primary care obstetric clinics showed genotypes not found commonly in hospital-acquired MRSA (HA-MRSA) strains, instead represented close relatedness with those of CA-MRSA strains. This suggests that CA-MRSA can spread by mediation of primary clinics with low antibiotic pressure, and there is a possibility that CA-MRSA is transmitted into hospitals.