Colonization Rate and Serotypes of Group B Streptococci in First Trimester of Pregnancy

Uh, Young; Jang, In Ho; Yoon, Kap Jun; Kwon, Jang Yeon

Abstract

BACKGROUND: Group B streptococci (GBS) are the most common cause of sepsis and meningitis in newborns in the United States and Europe, and maternal colonization rate of GBS is the most important factor of group B streptococcal neonatal infections. But, in Korea, studies on the maternal colonization rate of GBS are rare due to low incidence of neonatal group B streptococcal infections, particularly, data on colonization rate of GBS during first trimester is nearly absent. The aim of this study was to establish the rates of maternal carriage of GBS and the distribution of GBS serotypes in first trimester of pregnancy.
METHODS
During the period of June to December 1997, we studied women attending private clinic. A total of 309 women in first trimester were enrolled in the study. Cotton swab specimens from vagina and cervix were placed to new Granada tube medium. The new Granada tube medium with specimen swab was incubated in 5% CO2 atmosphere at 35degreesC. For the identification of GBS, the colonies showing orange color on new Granada tube medium were tested with Streptex group B Streptococcus reagent (Wellcome Diagnostics, UK). Serotyping was done by Hemolytic Streptococcus Group B Typing Sera (Denka Seiken, Japan). The typing sera used in this study were Ia, Ib, II, III, IV, and V.
RESULTS
Of the pregnant women in first trimester, 2.3% (7/309) were colonized with GBS, and all seven women who colonized GBS were positive in vagina and cervix at the same time. Frequency of serotype III and Ib were 71.4% (5/7) and 29.6% (2/7), respectively. Serotypes Ia, II, VI, and V were absent.
CONCLUSIONS
Maternal carriage rate of GBS in first trimester of pregnancy was 2.3%, and serotype III was the most common serotype. Serotypes Ia, II, VI, and V were absent.