Performance of surveillance cultures at different body sites to identify asymptomatic Staphylococcus aureus carriers.

ABSTRACT

The objective was to evaluate the performance of surveillance cultures at various body sites for Staphylococcus aureus colonization in pregnant women and newborns (NB) and the factors associated with nasal colonization. For NB, 4 sites were evaluated nares, oropharynx, perineum, and umbilical stump (birth, third day, and weekly). For pregnant women, 4 sites during labor anterior nares, anus, perineum, and oropharynx. Nasally colonized patients were compared with colonized only extranasally. Colonization was 53% of 392 pregnant women (methicillin-resistant S. aureus [MRSA] 4%) and 47% of 382 NB (MRSA 9%). For newborn patients, the best body site was the umbilical stump (methicillin-susceptible S. aureus [MSSA] 64%; MRSA 68%) and the combination of nares + umbilical (MSSA 86%; MRSA 91%). Among pregnant women, the best body site was the anterior nares (MSSA 59%; MRSA 67%) and the combination of nares + oropharynx (MSSA 83%; MRSA 80%). A smaller number of household members were associated with MRSA carriage in pregnant women (2.2 ± 0.6 versus 3.6 ± 1.8; P = 0.04). In conclusion, multiple culture sites are needed. Control programs based on surveillance cultures may be compromised.