Vaginal microbiota in healthy pregnant women and prenatal screening of group B streptococci (GBS)

Abstract.

The microbiota of the lower female genital tract was evaluated from vaginal swabs obtained from 623 healthy pregnant women at gestation periods of 35–40 weeks. Isolated and identified microorganisms were expressed as percentages of total samples. As expected, lactobacilli made up the dominant vaginal microbiota (70%). Enterobacteriaceae, mainly Escherichia coli, Klebsiella spp. and Proteus, were present in 38% of the samples, which might reflect the possible contamination of vaginal tract with rectal microorganisms. Candida albicans was present in 10% of healthy pregnant woman assayed. Streptoccocci (Streptococcus sp. and Enterococcus faecalis with 3% and 4%, respectively) and other gram-positive cocci (Staphylococcus sp., 5%), along with other microorgansisms such as Gardnerella vaginalis (5%) and Pseudomonas aeruginosa (2%) may represent a potential infection risk. Streptococcus agalactiae (group B streptococci β-hemolytic, GBS) was detected in 7% of the samples. GBS infection is a leading cause of neonatal morbidity and mortality in the developed world. Furthermore, GBS was often co-isolated with C. albicans (54.5%) in the samples. A complete and detailed evaluation of the vaginal biota swab, with particular attention to the presence of potential pathogens such as GBS, is a preventive strategy that can provide useful information to obstetricians and gynecologist in managing the last days of pregnancy and delivery.