Oral Bacteria May Cause Uterine Infections

In a study by researchers at Case Western Reserve University (Cleveland, Ohio, USA), amniotic fluid, blood samples, vaginal swabs, and oral swabs were collected from 19 pregnant women who were undergoing transabdominal amniocentesis because of preterm labor or threatened preterm labor. The samples were analyzed for bacterial DNA via polymerase chain reaction (PCR) and nucleotide sequencing.

An as yet unnamed species of the bacterium genus Bergeyella was detected in the mouths of all 14 women tested, but in the amniotic fluid of only one patient with a uterine infection. That patient subsequently went into labor, induced by the infection, and delivered her baby at 24 weeks' gestation. Analysis of her placenta revealed severe and diffused chorioamnionitis and fetal vasculitis involving the umbilical cord and chorionic plate, which were the presumed cause of her preterm labor. However, the bacterium was not detected in the vaginal swab, as might be expected. The finding confirmed what some scientists have suspected: that intrauterine infections don't always ascend from the genital tract but can descend from the oral cavity. The study was published in the April 2006 issue of the Journal of Clinical Microbiology.

The study is an eye-opener, said lead author microbiologist Yiping W. Han, Ph.D. It shows that oral bacteria can get into the uterus.

The study also suggested that more than the usual bacterial suspects may be responsible for uterine infection and resulting preterm birth, Dr. Han added. The usual suspects are known vaginal flora such as Ureaplasma urealyticum or Mycoplasma hominis. But Bergeyella, a little-known, rod-shaped, Gram-negative bacteria associated with dog and cat bite wounds, had not been thought to be an important component of the oral or vaginal flora.



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