AUTHOR=Kumar Shakti , Kumari Naina , Talukdar Daizee , Kothidar Akansha , Sarkar Mousumi , Mehta Ojasvi , Kshetrapal Pallavi , Wadhwa Nitya , Thiruvengadam Ramachandran , Desiraju Bapu Koundinya , Nair G. Balakrish , Bhatnagar Shinjini , Mukherjee Souvik , Das Bhabatosh , GARBH-Ini Study Group , Bhatnagar Shinjini , Das Bhabatosh , Bal Vineeta , Desiraju Bapu Koundinya , Kshetrapal Pallavi , Misra Sumit , Natchu Uma Chandra Mouli , Rath Satyajit , Sachdeva Kanika , Sharma Dharmendra , Singh Amanpreet , Sopory Shailaja , Thiruvengadam Ramachandran , Wadhwa Nitya , Maitra Arindam , Majumder Partha P. , Mukherjee Souvik , Maiti Tushar K. , Bahl Monika , Bansal Shubra , Mehta Umesh , Sharma Sunita , Sindhu Brahmdeep , Arya Sugandha , Bharti Rekha , Chellani Harish , Mittal Pratima , Garg Anju , Ramji Siddharth , Khurana Ashok , Tripathi Reva , Gupta Yashdeep , Hari Smriti , Tandon Nikhil , Gupta Rakesh , Salunke Dinakar M. , Nair G Balakrish TITLE=The Vaginal Microbial Signatures of Preterm Birth Delivery in Indian Women JOURNAL=Frontiers in Cellular and Infection Microbiology VOLUME=11 YEAR=2021 URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2021.622474 DOI=10.3389/fcimb.2021.622474 ISSN=2235-2988 ABSTRACT=Background

The incidence of preterm birth (PTB) in India is around 13%. Specific bacterial communities or individual taxon living in the vaginal milieu of pregnant women is a potential risk factor for PTB and may play an important role in its pathophysiology. Besides, bacterial taxa associated with PTB vary across populations.

Objective

Conduct a comparative analysis of vaginal microbiome composition and microbial genomic repertoires of women who enrolled in the Interdisciplinary Group for Advanced Research on Birth Outcomes – A DBT India Initiative (GARBH-Ini) pregnancy cohort to identify bacterial taxa associated with term birth (TB) and PTB in Indian women.

Methods

Vaginal swabs were collected during all three trimesters from 38 pregnant Indian women who delivered spontaneous term (n=20) and preterm (n=18) neonates. Paired-end sequencing of V3-V4 region of 16S rRNA gene was performed using the metagenomic DNA isolated from vaginal swabs (n=115). Whole genome sequencing of bacterial species associated with birth outcomes was carried out by shotgun method. Lactobacillus species were grown anaerobically in the De Man, Rogosa and Sharpe (MRS) agar culture medium for isolation of genomic DNA and whole genome sequencing.

Results

Vaginal microbiome of both term and preterm samples reveals similar alpha diversity indices. However, significantly higher abundance of Lactobacillus iners (p-value All_Trimesters<0.02), Megasphaera sp (p-value1st_Trimester <0.05), Gardnerella vaginalis (p-value2nd_Trimester= 0.01) and Sneathia sanguinegens (p-value2nd_Trimester <0.0001) were identified in preterm samples whereas higher abundance of L. gasseri (p-value3rd_Trimester =0.010) was observed in term samples by Wilcoxon rank-sum test. The relative abundance of L. iners, and Megasphaera sp. were found to be significantly different over time between term and preterm mothers. Analyses of the representative genomes of L. crispatus and L. gasseri indicate presence of secretory transcriptional regulator and several ribosomally synthesized antimicrobial peptides correlated with anti-inflammatory condition in the vagina. These findings indicate protective role of L. crispatus and L. gasseri in reducing the risk of PTB.

Conclusion

Our findings indicate that the dominance of specific Lactobacillus species and few other facultative anaerobes are associated with birth outcomes.