Risk factors for neonatal methicillin-resistant Staphylococcus aureus infection in a well-infant nursery.

OBJECTIVE

To determine risk factors for neonatal methicillin-resistant Staphylococcus aureus (MRSA) skin and soft-tissue infection in a well-infant nursery.

DESIGN

Case-control studies.

SETTING

A well-infant nursery in a nonteaching, community hospital.

METHODS

Case infants were newborns in the nursery who were born in the period November 2003 through June 2004 and had onset of MRSA skin and soft-tissue infection within 21 days after discharge from the nursery. Site inspections were conducted. Control infants were randomly selected male infants in the nursery during the outbreak periods. MRSA isolates were characterized with pulsed-field gel electrophoresis.

RESULTS

Eleven case infants were identified in 2 outbreaks: outbreak 1 occurred from November 18 through December 24, 2003, and outbreak 2 occurred from May 26 through June 5, 2004. All were full-term male infants with pustular-vesicular lesions in the groin. Inspection revealed uncovered circumcision equipment, multiple-dose lidocaine vials, and inadequate hand hygiene practices. In outbreak 1, case infants (n=6) had a significantly higher mean length of stay than control infants (3.7 vs 2.5 days; P=.01). In outbreak 2, case infants (n=5) were more likely to have been circumcised in the nursery (OR, undefined [95% CI, 1.7 to undefined]) and to have received lidocaine injections (OR, undefined [95% CI, 2.6 to undefined]). Controlling for length of stay, case infants were more likely to have been circumcised in the nursery (OR, 12.2 [95% CI, 1.5 to undefined]). Pulsed-field gel electrophoresis showed that 7 available isolates were indistinguishable from a community-associated MRSA strain (USA300-0114).

CONCLUSIONS

Newborns in well-infant nurseries are at risk for nosocomial infection with community-associated MRSA strains. Reducing length of stay, improving circumcision and hand hygiene practices, and eliminating use of multiple-dose lidocaine vials should decrease transmission of community-associated MRSA strains in nurseries.