Staph Found in 11% of Vaginal-Rectal Specimens


SAN FRANCISCO — Staphylococcus aureus was carried in the vaginal-rectal area in 11% of screened pregnant women at a Camden, N.J., hospital, according to a study presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.

The investigators took vaginal-rectal specimens collected from pregnant women being screened for group B streptococcus from June 2005 until March 2006 and cultured them for S. aureus.

Of 353 women screened, 39 (11%) were colonized with staphylococcus; 7 of the 39 (2%) were methicillin-resistant strains, said Dr. Henry Fraimow of Cooper University Hospital in Camden. Five of the seven MRSA isolates contained the Panton-Valentine leukocidin virulence gene.

All seven were susceptible to clindamycin and levofloxacin.

The study could help to explain why in Camden generally half of S. aureus abscesses occur below the waist, and why Camden nurseries have had outbreaks of neonatal S. aureus infections, Dr. Fraimow said at the conference, which was sponsored by the American Society for Microbiology.

“This is higher than reported rates of vaginal colonization with staph aureus, most [studies] of which were done in the 1980s during some of the toxic shock syndrome outbreaks,” he said. “There hasn't been a lot of good recent data.”

One other recent study that looked at vaginal colonization found a higher rate of carriage, 18%, but a lower rate of methicillin resistance, 0.5%, he added.

Dr. Fraimow and his colleagues also found much more carriage in the summer months than during the rest of the year. They found that 14% of the specimens collected between June and September were colonized, compared with only 7% of those collected between October and March.

“We also conclude that all reservoirs for this organism must be considered when looking at strategies such as decolonization to prevent recurrent infections,” Dr. Fraimow said.

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