Genital tract colonization with methicillin-resistant staphylococcus aureus (MRSA) is not associated with a high risk for early-onset invasive neonatal infection

Abstract

CUS AUREUS (MRSA) IS NOT ASSOCIATED WITH A HIGH RISK FOR EARLY-ONSET INVASIVE NEONATAL INFECTION WILLIAM ANDREWS, ROBERT SCHELONKA, SUZANNE CLIVER, MARTHA LYON, KEN WAITES, STEPHEN MOSER, A. STAMM, University of Alabama at Birmingham, Obstetrics/Gynecology, Birmingham, Alabama, University of Alabama at Birmingham, Pediatrics-Neonatology, Birmingham, Alabama, University of Alabama at Birmingham, Pathology, Birmingham, Alabama, University of Alabama at Birmingham, Medicine, Birmingham, Alabama OBJECTIVE: To determine the rate of genital tract colonization with MRSA among pregnant women and assess the association between MRSA colonization and early-onset invasive neonatal infection. STUDY DESIGN: Between July 2003 and June 2006, recto-vaginal screening cultures for group B Streptococcus (GBS) were obtained between 35 and 37 weeks’ gestation. The presence of Staphylococcus aureus and MRSA was determined in these cultures using standard microbiological techniques. The results were compared to a database including all neonates with a positive MRSA cuture delivered to these mothers. RESULTS: 5732 pregnancies had screening culture results and infant infection data available. 22.9% of the mothers were positive for GBS, 14.5% for S. aureus of which 24.3% were MRSA (overall 4% maternal colonization with MRSA). Two infants whose mothers were MRSA-positive had positive MRSA cultures from a sterile site. One had a positive blood culture at two months of age. Following a vaginal delivery at 36 weeks’, this infant was transferred to another hospital for a truncus arteriosus repair then transferred back to the delivery hospital. The other had a positive CSF culture with a negative corresponding blood culture. This neonate was cultured during an initial episode of transient tachypnea following a vaginal delivery at 40 weeks’. The tachypnea rapidly resolved. The neonate was transferred to the well-baby nursery and remained asymptomatic. The managing clinicians felt that the positive CSF culture represented surface contamination and not MRSA meningitis. The MRSA isolates from this mother-infant pair were identical when compared by pulsed field gel electrophoresis and were also identical to another MRSA clone isolated from other patients in our hospital. These isolates did not match the predominant local MRSA clone associated with communityacquired MRSA infections. CONCLUSION: Recto-vaginal MRSA colonization is not uncommon among pregnant women, but does not appear to be associated with a high risk of vertically transmitted invasive early-onset infection in the neonate. S40 SMFM Abstracts