[Characteristics of group b streptococcus vertical transmission]

The goal of this study was to compare the characteristics of group B streptococcus (GBS) or Streptococcus agalactiae vertical transmission in woman, receiving or not intrapartum. antimicrobial prophylaxis, at risk of delivering an infant with GRS disease.

The study included 330 women, with risk factors for delivering an infant with GBS disease. The vaginal GBS colonization was studied by conventional culture. A clinical and microbiological follow-up was done in both women and neonates.

GHS was detected in 37 women (11.2%). Among these, 21 (56.8%) received intrapartum antibiotics and 16 (43.2%) did not. Forty-one neonates were born from these 37 women. Of these, 11 showed signs of infection (3 with positive blood culture and 8 with blood culture negative for GBS) and 2 presented an asymptomatic bacteremia A GBS neonatal infection (with positive blood culture) was produced in 4.8% of newborns from mothers who received intrapartum antibiotics versus 25% of newborns from mothers who did not receive intrapartum antibiotics. However, this difference was not significant nor was the difference between external colonization by GBS between these two groups of newborns. On the contrary, significant differences were found in the percentage of clinically suspected sepsis (with negative blood cultures), which was more frequent among newborns from mothers without intrapartum antibiotics (30.4% vs 5.6%). A good correlation between the intensity of vaginal colonization and the incidence of microbiologically demonstrated sepsis, suspected sepsis an asymptomatic bacteremia in the newborn was found.

In conclusion, in order to minimize the vertical transmission of GBS, the most efficient strategy seems to be to offer antibiotic prophylaxis to women identified as GBS carriers, since the antibiotic administration to women with "obstetric risks" often means that it is impossible that two hours elapse between antibiotic administration and delivery, resulting in the loss of efficacy of this second strategy.