The prevalence and risk factors of group B streptococcus colonization in Iranian pregnant women

BACKGROUND: Group B Streptococcus (GBS) is a leading cause of serious neonatal infections. Although great progress has been made in preventing prenatal GBS, its colonization rate in different regions of Iran remains unknown. AIM: To determine GBS colonization prevalence and its risk factors among Iranian pregnant women. METHODS: This prospective cross-sectional study was performed on 186 pregnant women, who attended Boo-Ali hospital which is affiliated with Islamic Azad University in Tehran, Iran, from March 2014 to June 2015. The demographic, obstetric and gynecological data were gathered. A recto-vaginal culture was taken from each patient, with a sterile swab, in lithotomy position without using speculum, and vaginal pH was measured. Patients with positive GBS received IV antibiotic therapy during labor (penicillin G 3 gram at first dose then 1.5 gram Q/4h until delivery). Data were analyzed by statistical software SPSS version 21. Statistical tests for differences were performed by Chi-square test. Potential confounding was assessed by logistic regression. Level of significance was set at p<0.05. RESULTS: Twenty-two (11.8%) patients had positive recto-vaginal colonization. No significant differences between colonized and GBS-negative women with regard to age, obstetrics history and socio-economic factor were noticed. In contrast, smoking, history of previous infection with HPV, presence of vulvitis and a vaginal pH>4.5 were associated with GBS colonization (p≤0.05). CONCLUSIONS: With a relatively low prevalence and few significantly correlated factors, it is hardly possible to define a high risk group of pregnant women for GBS colonization. Therefore, thorough measures should be taken in order to prevent infection complications in mothers and neonates in the Iranian population.