Rectovaginal Staphylococcus aureus colonization: is it a neonatal threat?

We sought to determine the rate of Staphylococcus aureus rectovaginal colonization and positive newborn blood cultures. Routinely obtained group B streptococcus (GBS) rectovaginal specimens were cultured for S. aureus using standard microbiology procedures. S. aureus- and GBS-positive blood cultures in infants less than 3 days old were determined from our microbiology database. Overall, 1488 rectovaginal cultures were obtained. Rates of positive GBS, S. aureus, and methicillin-resistant S. aureus (MRSA) cultures were 20.2%, 8.2%, and 1.7%, respectively. Cultures were positive for methicillin-susceptible S. aureus (MSSA) and GBS or MRSA and GBS in 1.6% and 0.3% of women, respectively. There was no association between GBS and MSSA or MRSA. From 1998 to 2008, there were four positive S. aureus blood cultures (0.4/10,000 live births). The rate of early onset GBS-positive blood cultures was 2.8/10,000 live births. S. aureus rectovaginal colonization at 35 to 37 weeks is relatively uncommon and currently does not appear to pose a significant risk of early onset neonatal sepsis.