Introduction
Maternal group B streptococcal (GBS) colonization is one of the most important risk factors for GBS disease in neonates. In 2002, the Centers for Disease Control (CDC) recommended universal culture-based screening of all pregnant women between 35-37 weeks gestation in order to treat all those positive for GBS with intrapartum antibiotics prior to delivery to prevent against early onset neonatal GBS sepsis.1 Ever since the institution of this policy, the incidence of early onset GBS sepsis has continued to fall dramatically from a rate of 1.5/1,000 to a rate of 0.24/1,000 live births.2
However, the prevalence of maternal GBS colonization among the population in this region has not been recently explored. The colonization rate varies from country to country, the geographic location, and the method used in determining the colonization. In the USA, carriage rates in the 70’s and 80’s ranged from 20% to 35%.3-5 In Africa, rates ranged from 20% to 30%.6-8 In Eastern Europe rates of 30+% have also been determined.9 In Western Europe rates ranged from a low of 14% to a high of 36%.5,10 In India the rates were as low as 15%,11 while in Korea, the rate was as low as 8%.12 In Australia, rates as high as 35% have been demonstrated.13 In summary, rates of GBS colonization have remained remarkably stable over the past 40 years.
Potential sociodemographic risk factors for GBS colonization among pregnant women have not been recently explored. Perusal of the literature within the last 2 decades demonstrates a paucity of information on other potential sociodemographic risk factors associated with maternal GBS colonization during pregnancy. One risk factor of GBS colonization of mothers of term or near term neonates not yet adequately explored is tobacco smoke exposure during pregnancy. Tobacco smoke has been shown to be associated with increased colonization of the respiratory, gastrointestinal, and even genital tract with various bacterial pathogens.14-21Because over 10% of women in the United States smoke during pregnancy, 22 it is important to determine whether smoking is a risk factor for GBS colonization. We therefore hypothesized that tobacco smoking during pregnancy is independently associated with increased GBS colonization among women delivering term or near term neonates in this tertiary care hospital in Virginia.