Survey of methicillin-resistant Staphylococcus aureus from neonates and the environment in the NICU.

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is a risk factor of nosocomial infection with compromised hosts including neonates. Currently, the prevalence of MRSA carriers among children is increasing in Japan. There are some reports of nosocomial infection caused by MRSA in a pediatric ward or neonatal intensive care unit (NICU). During 6 months (from January 2001 to June 2001), 37 MRSA strains were isolated from 37 neonates who were admitted in the NICU and 52 MRSA were strains isolated from NICU environments. We performed DNA typing of MRSA using an arbitrary primed-PCR method on these isolates. Thirty-seven clinical isolates were classified into four types (A type, 14; B type, 4; C type, 4; D type, 3; and others, 12). The A-type strains of MRSA continued to be isolated for more than 6 months. In the NICU environment, the detection rate of the A-type MRSA was 23.1% (12/52). The A-type strains were frequently isolated from environments around patients. The A-type strains of MRSA were prevalent in the NICU, probably due to nosocomial infection. Although none of the neonatal patients developed severe MRSA infection, the same genotype strains were persistently isolated during a period of more than 6 months from patients and the NICU environment around patients. Environmental control around neonatal patients is important to prevent nosocomial infection in the NICU.