Rapid PCR could cut intrapartum antibiotic use.(Obstetrics)

Washington -- Use of real-time polymerase chain reaction to screen for group B Streptococcus in the delivery room could reduce the use of intrapartum antibiotics by more than half, compared with antenatal screening alone, the findings of a single-center study of 232 pregnant women suggest.

Current CDC guidelines call for vaginal and rectal swabs at 35-37 weeks' gestation and for all women with cultures positive for group B Streptococcus (GBS) to receive intravenous antibiotic prophylaxis during labor and delivery (MMWR 2002;51[RR1 l]:l-22). This practice has greatly reduced the rates of neonatal sepsis in the United States, but it is imperfect. Women whose status is unknown at the time of labor also must receive prophylaxis, resulting in overtreatment, while cultures can fail to detect GBS in women who are lightly colonized, resulting in failure to treat.

Rapid testing at the time of delivery using real-time polymerase chain reaction (RT-PCR) has the potential to solve these problems, Dr. Stefan Gerber and his associates said in a poster presentation at the jointly held annual Interscience Conference on Antimicrobial Agents and Chemotherapy and the annual meeting of the Infectious Diseases Society of America.

Of 232 women presenting for vaginal birth at University Center Hospital, Lausanne (Switzerland) in an 8-month span, 19% (44) had positive GBS cultures at 35-37 weeks, 65% (152) had negative cultures, and 16% (36) had unknown GBS status at the time of delivery Per the guidelines, 34% of the women (80) received prophylactic antibiotics during labor, but treatment was completed (at least two doses or at least 4 hours of intravenous antibiotics) in just 21% (17).

Lower vaginal and rectal swabs were obtained in all the women in the delivery room, and GBS detection was performed by both culture and RT-PCR, using Cepheid's Xpert GBS test, which ...