[Prevention of vertical transmission of Group B Streptococcus]

Group B Streptococcus (GBS) are pathogens that involve a risk of vertical transmission. They are the infecting organism in approximately one quarter of all cases of neonatal sepsis and meningitis, making prevention of GBS infection an important goal. The United States Centers for Disease Control and Prevention (CDC) recommends administration of antibiotic prophylaxis to GBS-colonized pregnant women at least 4 hours before delivery, but the time of antibiotic prophylaxis administration is not generally reported in Japan. The purpose of the present study was to identify the care provided to GBS-colonized pregnant and intrapartum women in order to prevent of vertical transmission of GBS. The subjects were women (n=150) judged during pregnancy to have been colonized by GBS, who delivered vaginally at one of two hospitals between January 2000 and December 2004, and their neonates (n=151). The relation between the care provided and GBS transmission was analyzed. GBS was transmitted to the neonates of 18 of the 150 women (transmission rate 12.0%). The relation between transmission to the neonate and time between administration of antibiotic prophylaxis and delivery was investigated, and transmission to the neonate was found to be significantly greater when it was less than 3.5 hours (transmission to 9 neonates of 53 women) than more than 3.5 hours (transmission 4 neonates of 83 women) (p < 0.05). The time between admission and delivery was significantly shorter in the cases of transmission (p < 0.05). This indicates the need for thorough health guidance for expectant mothers, especially multipara, during pregnancy regarding the timing of admission for delivery, in order to ensure sufficient time between administration of antibiotic prophylaxis and delivery.