Why do lactobacilli dominate the human vaginal microbiota?

Witkin, SS; Linhares, Iara M.

doi:10.1111/1471-0528.14390

Cited by 199 publications

(189 citation statements)

References 58 publications

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“…in the lower reproductive tract is well described and can be partly attributed to lactic acid‐driven acidification of the vagina, which inhibits growth and colonisation of other pathogenic species . Furthermore, lactic acid can suppress production of inflammatory mediators in the vagina . Data from our cohort allow us to conclude that the protective role of Lactobacillus spp.…”

Section: Discussionmentioning

confidence: 66%

The association between vaginal bacterial composition and miscarriage: a nested case–control study

Al‐Memar

Bobdiwala

Fourie

et al. 2019

BJOG

109

110

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Objective To characterise vaginal bacterial composition in early pregnancy and investigate its relationship with first and second trimester miscarriages.Design Nested case-control study.Setting Queen Charlotte's and Chelsea Hospital, Imperial College Healthcare NHS Trust, London.Population 161 pregnancies: 64 resulting in first trimester miscarriage, 14 in second trimester miscarriage and 83 term pregnancies.Methods Prospective profiling and comparison of vaginal bacteria composition using 16S rRNA gene-based metataxonomics from 5 weeks' gestation in pregnancies ending in miscarriage or uncomplicated term deliveries matched for age, gestation and body mass index.Main outcome measures Relative vaginal bacteria abundance, diversity and richness. Pregnancy outcomes defined as first or second trimester miscarriage, or uncomplicated term delivery.Results First trimester miscarriage associated with reduced prevalence of Lactobacillus spp.-dominated vaginal microbiota classified using hierarchical clustering analysis (65.6 versus 87.7%; P = 0.005), higher alpha diversity (mean Inverse Simpson Index 2.5 [95% confidence interval 1.8-3.0] versus 1.5 [1.3-1.7], P = 0.003) and higher richness 25.1 (18.5-31.7) versus 16.7 (13.4-20), P = 0.017), compared with viable pregnancies. This was independent of vaginal bleeding and observable before first trimester miscarriage diagnosis (P = 0.015). Incomplete/complete miscarriage associated with higher proportions of Lactobacillus spp.-depleted communities compared with missed miscarriage. Early pregnancy vaginal bacterial stability was similar between miscarriage and term pregnancies.Conclusions These findings associate the bacterial component of vaginal microbiota with first trimester miscarriage and indicate suboptimal community composition is established in early pregnancy. While further studies are required to elucidate the mechanism, vaginal bacterial composition may represent a modifiable risk factor for first trimester miscarriage.Keywords First trimester miscarriage, second trimester miscarriage, vaginal bacteria, vaginal microbiome.Tweetable abstract Vaginal bacterial composition in first trimester miscarriage is associated with reduced Lactobacillus spp. abundance and is independent of vaginal bleeding.

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Section: Discussionmentioning

confidence: 66%

The association between vaginal bacterial composition and miscarriage: a nested case–control study

Al‐Memar

Bobdiwala

Fourie

et al. 2019

BJOG

109

110

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“…In our study, we observed that L. crispatus (99%)/ L. acidophilus (99%) at early gestation may be associated with decreased risk of spontaneous preterm birth, which is similar to recent findings from two UK studies (in predominantly white populations) and a study consisting of two cohorts of white and African American women . Among other lactobacilli, L. crispatus has the largest genome, and potential bacteriocin and adhesin genes . Stafford et al, recently reported a positive association between L. crispatus and succinate levels.…”

Section: Discussionmentioning

confidence: 99%

Vaginal microbiome in early pregnancy and subsequent risk of spontaneous preterm birth: a case–control study

Tabatabaei

Eren

Barreiro

et al. 2018

BJOG

153

116

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“…Lactobacilli dominate the vaginal microbiome in the majority of reproductive-age women (38), but not in any other mammal, including nonhuman primates (39,40). The evolution of Lactobacillus dominance in humans may have been a response to the unique sexual behavior of humans and the need to prevent genital tract infections that interfere with fertility and pregnancy (40). Lactobacilli kill vaginal pathogens, including C. trachomatis (41).…”

Section: Trachomatis Persistencementioning

confidence: 99%

Chlamydia trachomatis: the Persistent Pathogen

Witkin

Minis

Athanasiou

et al. 2017

Clin Vaccine Immunol

165

117

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Chlamydia trachomatis is an obligate intracellular bacterium whose only natural host is humans. Although presenting as asymptomatic in most women, genital tract chlamydial infections are a leading cause of pelvic inflammatory disease, tubal factor infertility, and ectopic pregnancy. C. trachomatis has evolved successful mechanisms to avoid destruction by autophagy and the host immune system and persist within host epithelial cells. The intracellular form of this organism, the reticulate body, can enter into a persistent nonreplicative but viable state under unfavorable conditions. The infectious form of the organism, the elementary body, is again generated when the immune attack subsides. In its persistent form, C. trachomatis ceases to produce its major structural and membrane components, but synthesis of its 60-kDa heat shock protein (hsp60) is greatly upregulated and released from the cell. The immune response to hsp60, perhaps exacerbated by repeated cycles of productive infection and persistence, may promote damage to fallopian tube epithelial cells, scar formation, and tubal occlusion. The chlamydial and human hsp60 proteins are very similar, and hsp60 is one of the first proteins produced by newly formed embryos. Thus, the development of immunity to epitopes in the chlamydial hsp60 that are also present in the corresponding human hsp60 may increase susceptibility to pregnancy failure in infected women. Delineation of host factors that increase the likelihood that C. trachomatis will avoid immune destruction and survive within host epithelial cells and utilization of this knowledge to design individualized preventative and treatment protocols are needed to more effectively combat infections by this persistent pathogen.

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Why do lactobacilli dominate the human vaginal microbiota?

Abstract: Lactobacilli prevent infection without inducing inflammation to maximise fertility and pregnancy outcome.

Cited by 199 publications

References 58 publications

The association between vaginal bacterial composition and miscarriage: a nested case–control study

The association between vaginal bacterial composition and miscarriage: a nested case–control study

Vaginal microbiome in early pregnancy and subsequent risk of spontaneous preterm birth: a case–control study

Chlamydia trachomatis: the Persistent Pathogen

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