Prevalence and risk factors of Streptococcus agalactiae (group B) colonization in mothers and neonatal contamination at Srinagarind Hospital.

From July 1999 to November 1999, 901 pregnant women at Srinagarind Hospital, who fulfilled the criteria and had signed consent forms, were cultured from the lower vagina and perineum for group B streptococcus (GBS). Their neonates were also cultured from ears and anuses within 30 minutes after birth. There were 56 cases or 6.22 per cent colonization in pregnant mothers at the onset of labor and 14 cases or 1.55 per cent colonization in their neonates. Risk factors for GBS colonization in mothers were intrapartum fever and episiotomy. The risk factors for GBS colonization in the neonates were; 1. husband's occupation, 2. antepartum fever, 3. intrapartum fever, 4. postpartum morbidity and 5. gestational age. No cases during the study period had clinical infection from GBS. The prevalence rate in this study was much lower than the United States but similar to many developing countries. At this moment, it is not possible to culture for GBS in all pregnant women in Thailand. Intrapartum antibiotic prophylaxis for GBS infection was recommended if, 1. maternal fever was more than 38 degrees C, 2. ruptured membranes of more than 18 hours and 3. previous birth with neonatal GBS infection.