Bacterial vaginosis as a risk factor for high-grade cervical lesions and cancer in HIV-seropositive women

Vaginal microbiome components as correlates of cervical human papillomavirus infection

BACKGROUND

The interplay between vaginal microbiome and human papillomavirus (HPV) remains unclear, partly due to heterogeneity of the microbiota.

METHODS

We used data from 546 women enrolled in a cross-sectional study conducted in five Brazilian regions. We genotyped vaginal samples for HPV and sequenced V3-V4 region of 16S rRNA gene for vaginal microbiome analysis. We used stepwise logistic regression to construct two linear scores to predict high-risk HPV (hrHPV) positivity: one based exclusively on presence of individual bacterial taxa (microbiome-based [MB] score) and the other exclusively on participants' sociodemographic, behavioral and clinical (SBC) characteristics. The MB score combined coefficients of 30 (out of 116) species. The SBC score retained six out of 25 candidate variables. We constructed receiver operating characteristic curves for the scores as hrHPV correlates and compared areas under the curve (AUC) and 95% confidence intervals (CI).

RESULTS

Overall, prevalence of hrHPV was 15.8%, and 26.2% had a Lactobacillus-depleted microbiome. The AUCs were 0.8022 (CI:0.7517-0.8527) for MB score and 0.7027 (CI:0.6419-0.7636) for SBC score (P=0.0163).

CONCLUSIONS

The proposed MB score is strongly correlated with hrHPV positivity - exceeding the predictive value of behavioral variables - suggesting its potential as an indicator of infection and possible value for clinical risk stratification.

Vaginal dysbiosis and the risk of human papillomavirus and cervical cancer: systematic review and meta-analysis

OBJECTIVE

The vaginal microbiota proposedly influence the association between human papillomavirus and cervical cancer. Our aim was to assess whether vaginal dysbiosis affects human papilloma virus acquisition, persistence, and progression to related cervical premalignancy.

DATA SORUCES

MEDLINE, Embase, CINAHL, Cochrane Library, and Web of Science (inception until June 2018) were used for this study. The study protocol was registered at PROSPERO (CRD42016035620).

STUDY ELIGIBILITY CRITERIA

This systematic review included all observational studies reporting on incident human papilloma virus, persistent human papilloma virus, and/or related cervical disease in women with or without vaginal dysbiosis prior to outcome assessment.

STUDY APPRAISAL AND SYNTHESIS METHODS

We used random-effects models for meta-analyses and report pooled relative risks with 95% confidence intervals. The risk for incident and/or persistent human papilloma virus or related cervical disease based on longitudinal results was determined.

RESULTS

Of 1645 unique articles, 15 mainly prospective cohort studies were included, published between 2003 and 2017, including a total of 101,049 women. Vaginal dysbiosis was associated with an increased risk of incident human papilloma virus (overall relative risk, 1.33, 1.18-1.50, I² = 0%; among young women relative risk, 1.43, 1.10-1.85, I² = 0%), human papilloma virus persistence (overall relative risk, 1.14, 1.01-1.28, I² = 44.2%; for oncogenic types relative risk, 1.18, 1.01-1.38, I² = 0%), and high-grade lesions and cancer (relative risk, 2.01, 1.40-3.01, I² = 0%), but women with lesions/cancer were compared with those without, regardless of their oncogenic human papilloma virus status. Overall, comparable results were found in the molecular vaginal microbiota studies.

CONCLUSION

This study supports a causal link between vaginal dysbiosis and cervical cancer along the oncogenic human papillomavirus acquisition, persistence, and cervicovaginal dysplasia development pathway.

Individualized medicine and the microbiome in reproductive tract

Humans have evolved along with the millions of microorganisms that populate their bodies. These microbes (10(14)) outnumber human cells by 10 to 1 and account for 3 × 10(6) genes, more than ten times the 25,000 human genes. This microbial metagenome acts as our "other genome" and like our own genes, is unique to the individual. Recent international efforts such as the Human Microbiome Project (HMP) and the MetaHIT Project have helped catalog these microbial genomes using culture-independent, high-throughput, next-generation sequencing. This manuscript will describe recent efforts to define microbial diversity in the female reproductive tract because of the impact that microbial function has on reproductive efficiency. In this review, we will discuss current evidence that microbial communities are critical for maintaining reproductive health and how perturbations of microbial community structures can impact reproductive health from the aspect of infection, reproductive cyclicity, pregnancy, and disease states. Investigations of the human microbiome are propelling interventional strategies from treating medical populations to treating individual patients. In particular, we highlight how understanding and defining microbial community structures in different disease and physiological states have lead to the discovery of biomarkers and, more importantly, the development and implementation of microbial intervention strategies (probiotics) into modern day medicine. Finally this review will conclude with a literature summary of the effectiveness of microbial intervention strategies that have been implemented in animal and human models of disease and the potential for integrating these microbial intervention strategies into standard clinical practice.