Colonization rates and serotypes of group B streptococci isolated from pregnant women in a Korean Tertiary Hospital

In a study designed to provide data on the rates of maternal carriage of group B streptococci (GBS) in Korean women, vaginal, anorectal, and urethral swab specimens from 459 pregnant women and ear canal and umbilicus swabs from their 288 neonates were cultured with new Granada medium and selective Todd-Hewitt broth. Additionally, the serotypes of 64 isolates of GBS and the minimal inhibitory concentrations of seven antimicrobial agents for these isolates were determined. The rate of colonization by GBS in pregnant women and in their babies was 5.9% (27/459) and 0.7% (2/288), respectively. The rates of resistance of GBS isolated from pregnant women were 13.3% to clindamycin, 5% to erythromycin, and 98.3% to tetracycline. The majority of GBS isolates from pregnant women belonged to serotypes Ib (48.3%), Ia (24.1%), and III (20.7%).