Dangerous Strep Bug Can Be Spread by Oral Sex

A bacterial infection dangerous to infants can be spread by sexual activity, particularly oral sex, between men and women, new study findings show. Group B streptococcal infection (GBS) rarely makes healthy young adults sick, but it can cause health problems for pregnant women and babies and can sicken elderly people or those with existing medical conditions, said lead investigator Dr. Betsy Foxman.

"Pregnant women who are colonized with GBS have a one in two chance of passing GBS to their newborn if they are not treated with antibiotics during labor and delivery," said Foxman, who is with the University of Michigan School of Public Health in Ann Arbor. Infection in newborns can cause neonatal sepsis -- a massive and potentially fatal immune response -- and meningitis, which can lead to brain damage and death, Foxman said. "Although GBS is treatable with antibiotics, increasingly, GBS is becoming resistant to antibiotics. Of every 100 newborn babies infected with GBS, four to six will die," she said.

The researchers evaluated 120 heterosexual couples for the presence of GBS. Each partner completed a questionnaire assessing sexual habits and risk factors for GBS.

"We demonstrated ... that among heterosexual couples co-colonized with GBS, 86 percent carried the identical strain. Further we identified engaging in oral sex as a risk factor for co-colonization with the identical strain," Foxman said. "While sexual activity between men and women has been suspected to be important in transmitting GBS, this is the first study to give tangible evidence that sexual transmission occurs."

Since male-to-female oral sex resulted in increased co-colonization with group B strep, Foxman advocates safe sex practices, such as using dental dams and condoms for oral sex, which "would minimize transmission via this route and prevent transmission of other sexually transmitted diseases as well." The article, "Determinants of Co-Colonization With Group B Streptococcus Among Heterosexual College Couples," appears in the September issue of Epidemiology (2002;13(5):533-539).

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