Vaginal Microbiome in Women With Preterm Birth and Those With Term Birth That Attended Anc at Thika Level 5 County Referral Hospital Between January 2019 and March 2019

Abstract

Vaginal microbiome influences pregnancy outcomes and the presence of vaginal dysbiosis has been shown to cause preterm birth. Approximately, there were 15 million preterm births per year, globally and 25% are attributable to vaginal dysbiosis. In Kenya, 1 in 6 under 5 deaths per year is attributable to preterm births. Traditionally, microscopy and culture has been the cornerstone of establishing the vaginal microbial composition. In the recent decades, use of non-culture techniques such as metagenomics has been shown to be more specific and sensitive thus superior to culture based techniques. Metagenomic based studies have shown that vaginal microbiome varies by race, geographical location, ethnicity, and diet among other variables. Our study objective was to determine the differences in vaginal microbiome in women with preterm birth and those with term birth at Thika Level 5 Hospital, Kenya. Methods: In this comparative case-control study, we utilized bio-banked high vaginal swabs. We had 39 cases and 67 controls that were selected through purposive sampling. DNA extraction was done using DNeasy Qiagen extraction kit. Gene sequencing and taxonomic profiling was then done using NGS Miseq illumina platform at Macrogen Inc. South Korea. Results: Lactobacillus iners was the most common bacteria found making CST 3 the most abundant at 64% and 67% in the cases and controls respectively but was present in 90|% of cases and 84% of the controls. CST 4 abundance was 28% in both cases and controls while CST 5 was dominant in 8% of cases and 5% of controls. CST 1 and 2 were not recorded in this study. However, there was one case of L. gasseri among preterm cases though this was not abundant enough to classify a woman as CST 2. CST 4 was present in 80% of the cases and 67% of the controls. The differences in the cases and controls were not statistically significant. Conclusion: We confirmed the dominance of CST 3 and 4 in pregnant African women. The study also showed the co-existence of CST 3 and 4, however, there was no association between a specific CST and the risk of preterm. Recommendations Longitudinal sampling at different gestational ages up to 6 weeks postpartum would enable the establishment of the stability of the vaginal microbiome throughout pregnancy and changes noted in the pueperium period. Cervical length is the best predictor of preterm, and since studies have shown that cervical length correlates to the diversity of the vaginal microbiome, future studies should involve both establishing the vaginal microbiome and cervical length simultaneously.