Comparison of the Genital Microbiomes of Pregnant Aboriginal and Non-aboriginal Women.

Nicole K Dinsdale,George L Mendz,Julie A Quinlivan,Natalia Castaño-Rodríguez

doi:10.3389/fcimb.2020.523764

Abstract

The genital microbiomes of women varies with racial background. Preterm birth and early-onset neonatal sepsis are two outcomes associated with genital infections during pregnancy. The rate of preterm birth in Aboriginal Australian mothers is high, as is the rate of early-onset sepsis in their infants. To date, no studies have been conducted to investigate genital microbiome taxa associated infection in this group of women. A prospective cohort study to characterize the vaginal and placental microbiomes of a group of these women from the Pilbara region was conducted at the Hedland Health Campus in Western Australia. Included in the study were gravidae Aboriginal (n = 23) and Non-aboriginal (n = 27) women in labor or for planned lower uterine segment Caesarean section. Employing sterile swabs, vaginal samples were obtained under sterile conditions immediately prior to vaginal delivery or planned Caesarean section; and placental samples were obtained under the same conditions during labor. Taxa present in the samples were identified by 16S rRNA amplicon sequencing (V4 region, 515F-806R). Taxon identity and abundance were established from Operational Taxonomic Unit (OTU) counts. Statistical analyses combining clinical metadata and sequencing results were employed to determine associations of taxa with racial background. The findings of this work served to enhance the current understanding of microbiota associated with health and disease in Aboriginal and Non-Aboriginal women. Differences were found between the vaginal and placental microbiomes of Aboriginal and Non-aboriginal women during pregnancy, as well as notable differences between the abundance of specific taxa in each racial group. The relative abundances of specific taxa were significantly different between participants with clinical signs of infection and those with healthy pregnancies. This work will contribute to understanding the causes of differences in rates of infection-driven preterm birth in various racial populations.

Highlights

Genital bacterial community profiles differ with racial background
Flavobacterium has been found as a common contaminant in reagents, but after applying the quality control with the reagents employed in the sequencing and in the analyses described in the Methods section, this taxon appeared at significant relative abundances in a number of placental microbiomes of both Aboriginal and Non-aboriginal women, and at over twice the abundance in the latter group of women
Considering that the Distance Linear Model (distLM) logistic regression confirmed that significant differences in microbiomes were due to racial background and genital location (Table 3), these results suggested that colonization with Pseudomonas is characteristic of the Aboriginal population of this study

Summary

Introduction

Genital bacterial community profiles differ with racial background. Dominant Lactobacillus in the vaginal flora of pregnant women is more prevalent amongst Caucasian and Asian women, and anaerobic bacterial communities are more common amongst African American and Hispanic women (Ma et al, 2012; Romero et al, 2014; MacIntyre et al, 2015; Freitas et al, 2017; Fettweis et al, 2019). The associations of intrauterine microbiota with racial background have been studied for placental samples of African, Caucasian and Chinese women (Zheng et al, 2015; Collado et al, 2016; Doyle et al, 2017; Gomez-Arango et al, 2017; Parnell et al, 2017; Zhou et al, 2018), but there are little data on the influence of racial background on other intra-amniotic bacterial populations. Knowledge of bacterial taxa residing in the vagina and placenta in normal pregnancies provides a foundation for healthcare professionals to identify abnormal flora, enabling the possibility of targeted prevention of genital infections

Objectives

Methods

Discussion

Conclusion