[Prevalence of maternal intrapartum colonization due to the Group-B Streptococus: epidemiological analysis in the province of Jaén (Spain).]

OBJECTIVE: Group B Streptococcus (GBS) infection remains to datey, without peripartum prophylaxis, the most common cause of vertically transmitted perinatal bacterial infection in the Western world. It is estimated that the prevalence of asymptomatic pregnant women with GBS in our country ranges between 10 and 20.5%, but there are few studies in this regard. With this research, we tried to establish the rate of pregnant women colonized by GBS at the recto-vaginal level at the time of delivery and to evaluate the validity of our strategy for the identification of pregnant women with GBS.

METHODS: A 290 women sample representative of pregnant population from the province of Jaén was randomly selected and the presence or absence of GBS in the recto-vaginal microbiota was determined on the day of delivery. Subsequently, a retrospective analysis was made, case by case, in order to establish whether the screening techniques applied during pregnancy had been able to correctly identify the state of GBS colonization at the time of delivery. Statistical techniques were applied to perform a descriptive sample analysis, which was complemented with a case-by-case concordance analysis for the two GBS determinations made over time for each subject (repeated observations over time on individuals from the same cohort).

RESULTS: The rate of pregnant women carrying GBS at the recto-vaginal level at the time of delivery was 23.10.

CONCLUSIONS: In our province, the rate of pregnant women with GBS at the time of delivery is higher than previously reported in the literature. Furthermore, our screening strategy during pregnancy could misclassify one of each eight women, causing one in sixteen GBS carriers to not be adequately identified.