Clinical and microbiological rationale for the prophylaxis of obstetric and perinatal pathology caused by group B streptococci

Background. Bacteriuria caused by group B streptococci (GBS) is a major risk factor for neonatal GBS associated pathology and a risk factor for pregnancy complications such as preterm birth and preterm rupture of membranes.

Objective. Clinical and microbiological rationale for the prophylaxis of obstetrical and perinatal pathology associated with group B streptococci. Methods. A total of 496 pregnant women who made their first prenatal visit within first 12 weeks of gestation were invited to participate. As clinical samples, mid-stream urine, vaginal swabs, rectal swabs from women and inguinal swabs, urine, meconium from newborn infants were used. GBS detection was performed using culture and PCR.

Results. The frequency of GBS detection was 16.3%. GBS associated bacteriuria was detected in 9.8% of the women. The women having GBS in urine at the beginning of pregnancy were significantly more often colonized with the microorganism late in pregnancy in comparison with the women with GBS-colonization of the vagina and/or rectum. Microbiological efficiency of antibiotic therapy of GBS associated bacteriuria using amoxicillin/clavulanic acid exceeded 70%. Clinical efficiency of the therapy consisted in the reduction of preterm birth and preterm rupture of membranes by 25% and 40%, respectively.

Conclusions. Antibiotic therapy of GBS associated bacteriuria results in a decrease of pregnancy complication, which necessitate its use. GBS-colonization of the vagina and rectum in pregnant women is transitory therefore antenatal screening for GBS aimed to prevent neonatal GBS-infection should be performed late in pregnancy or before delivery.