Comparison of culture-dependent and culture-independent molecular methods for characterization of vaginal microflora

Clinical vaginal-microecology testing using double-fluorescence staining in patients with high-risk human papillomavirus infection

High-risk human papillomavirus (hrHPV) infection is associated with cervical cancer; imbalanced vaginal microecology may contribute to HPV progression. Currently used methods for clinical vaginal-microecology (CVM) testing are associated with several disadvantages, such as low accuracy and complicated operation. This retrospective study presents a novel testing method to examine vaginal microecology via double-fluorescence staining and explores the relationship between hrHPV and CVM. We analyzed 1242 patients who underwent hrHPV testing at our hospital over a two-month period; of these, 695 also underwent clinical vaginal-microecology testing (CVMT). Patients underwent routine leukorrhea detection (n=322), functional testing (n=277), and our novel double-fluorescence staining-based CVMT approach (n=376). Patients with hrHPV exhibited more epithelial cells, miscellaneous bacteria, and hyphae than those without hrHPV on double-fluorescence staining-based CVMT approach. Double-fluorescence staining was effective in identifying indicators of hrHPV infection and may serve as an auxiliary tool for clinical hrHPV screening.

A Molecular Approach for Detecting Bacteria and Fungi in Healthcare Environment Aerosols: A Systematic Review

Molecular methods have become integral to microbiological research for microbial identification. This literature review focuses on the application of molecular methods in examining airborne bacteria and fungi in healthcare facilities. In January 2024, a comprehensive electronic search was carried out in esteemed databases including PubMed, Web of Science, and Scopus, employing carefully selected keywords such as ((bacteria) OR (virus) OR (fungi)) AND (aerosol) AND ((hospital) OR (healthcare) OR (dental office)) AND ((molecular) OR (PCR) OR (NGS) OR (RNA) OR (DNA) OR (metagenomic) OR (microarray)), following the PRISMA protocol. The review specifically targets healthcare environments with elevated concentrations of pathogenic bacteria. A total of 487 articles were initially identified, but only 13 met the inclusion criteria and were included in the review. The study disclosed that the prevalent molecular methodology for appraising aerosol quality encompassed the utilization of the PCR method, incorporating either 16S rRNA (bacteria) or 18S rRNA (fungi) amplification techniques. Notably, five diverse molecular techniques, specifically PFGE, DGGE, SBT, LAMP, and DNA hybridization methods, were implemented in five distinct studies. These molecular tests exhibited superior capabilities compared to traditional bacterial and fungal cultures, providing precise strain identification. Additionally, the molecular methods allowed the detection of gene sequences associated with antibiotic resistance. In conclusion, molecular testing offers significant advantages over classical microbiological culture, providing more comprehensive information.

Molecular Testing for the Diagnosis of Bacterial Vaginosis

Previously established diagnostic approaches for the diagnosis of bacterial vaginosis (BV), such as the Amsel criteria or the Nugent scoring system, do not always correspond to modern trends in understanding the etiology and pathogenesis of polymicrobial conditions. Inter-examiner variability and interpretation of data complicate the wet mount microscopy method. Gram staining of smears does not always provide reliable information regarding bacterial taxa, biofilms, or vaginal dysbiosis. Therefore, the introduction of molecular techniques into clinical practice is extremely relevant. Molecular approaches allow not only the diagnosis of BV but also provide an assessment of microbial composition, which is especially important in the differential diagnosis of vaginal infections. The current review represents an expert opinion on BV diagnosis and is based on extensive experience in the field of vaginal infection diagnosis and treatment.

Association of Pregnancy and HIV Status With Molecular-Bacterial Vaginosis in Indian Women

BACKGROUND

Bacterial vaginosis (BV) is a highly prevalent disorder of the cervicovaginal microbiota. Molecular-BV may put women at increased risk for adverse reproductive and obstetric outcomes. We investigated the association of HIV and pregnancy on the vaginal microbiota and associations with molecular-BV in women of reproductive age from Pune, India.

SETTING

We studied vaginal samples from N = 170 women, including N = 44 nonpregnant HIV seronegative, N = 56 pregnant seronegative, N = 47 nonpregnant women with HIV (WWH), and N = 23 pregnant WWH, and collected data on clinical, behavioral, and demographic factors.

METHODS

We used 16S rRNA gene amplicon sequencing to characterize the composition of the vaginal microbiota. We classified the vaginal microbiota of these women into community state types based on bacterial composition and relative abundance and further categorized them into molecular-BV versus Lactobacillus -dominated states. To determine associations between pregnancy and HIV status with outcome of molecular-BV, logistic regression models were used.

RESULTS

There was a high prevalence of molecular-BV (30%) in this cohort. We found that pregnancy was associated with decreased odds of molecular-BV (adjusted OR = 0.35, 95% CI: 0.14 to 0.87), while HIV was associated with increased odds of molecular-BV (adjusted OR = 2.76, 95% CI: 1.33 to 5.73), even when controlling for multiple relevant factors such as age, number of sexual partners, condom use, and douching.

CONCLUSION

Larger and longitudinal studies are needed to further characterize molecular-BV and the vaginal microbiota in pregnant women and WWH and relate these factors to infectious, reproductive, and obstetric outcomes. In the long term, these studies may lead to novel microbiota-based therapeutics to improve women's reproductive and obstetric health.

Correlations of joint detection of 22 vaginal microbes with routine examination results of vaginal secretions and assisted reproductive outcomes

The correlations of joint detection of 22 vaginal microbes with routine examination results of vaginal secretions and assisted reproductive outcomes were investigated. There were 37 samples with abnormal vaginal microecology in 107 vaginal secretion samples. The top 5 detection rates of microorganisms were Ureaplasma urealyticum (73.83%), Prevotella sp. (70.09%), Gardnerella vaginalis (53.27%), L. crispatus (52.34%) and L. inerts (51.40%). When the levels of Bacillus and hydrogen peroxide in vaginal secretions decreased or pH increased, the abnormal rates of vaginal microecology increased significantly (P < 0.01). The clinical pregnancy rate (53.66%, 22/41) in the women with normal vaginal microecology was higher than that (37.5%, 9/24) with abnormal vaginal microecology. In conclusions, the joint detection of 22 vaginal microbes can quickly and effectively determine whether the vaginal microecology is normal or not. The evaluation of vaginal microecology may be valuable in predicting the assisted reproductive outcomes of infertile women.

Understanding respiratory microbiome-immune system interactions in health and disease

Interactions between the developing microbiome and maturing immune system in early life are critical for establishment of a homeostasis beneficial to both host and commensals. The lung harbors a diverse community of microbes associated with health and local or systemic disease. We discuss how early life colonization and community changes correlate with immune development and health and disease throughout infancy, childhood, and adult life. We highlight key advances in microbiology, immunology, and computational biology that allow investigation of the functional relevance of interactions between the respiratory microbiome and host immune system, which may unlock the potential for microbiome-based therapeutics.

Isolation and Identification of Lactic Acid Bacteria from Natural Whey Cultures of Buffalo and Cow Milk

In southern Italy, some artisanal farms produce mozzarella and caciocavallo cheeses by using natural whey starter (NWS), whose microbial diversity is responsible for the characteristic flavor and texture of the final product. We studied the microbial community of NWS cultures of cow’s milk (NWSc) for the production of caciocavallo and buffalo’s milk (NWSb) for the production of mozzarella, both from artisanal farms. Bacterial identification at species and strain level was based on an integrative strategy, combining culture-dependent (sequencing of the 16S rDNA, species/subspecies-specific Polymerase Chain Reaction (PCR) and clustering by Random Amplified Polymorphic DNA-Polymerase Chain Reaction (RAPD-PCR) and culture-independent (next-generation sequencing analysis, NGS) approaches. Results obtained with both approaches showed the occurrence of five species of lactic acid bacteria in NWSb (Lactococcus lactis subsp. lactis, Lactobacillus fermentum, Streptococcus thermophilus, Lactobacillus delbrueckii, and Lactobacillus helveticus) and five species in NWSc (Lc. lactis subsp. lactis, Enterococcus faecium, and S. thermophilus, Lb. helveticus, and Lb. delbrueckii), with the last two found only by the NGS analysis. Moreover, RAPD profiles, performed on Lc. lactis subsp. lactis different isolates from both NWSs, showed nine strains in NWSb and seven strains in NWSc, showing a microbial diversity also at strain level. Characterization of the microbiota of natural whey starters aims to collect new starter bacteria to use for tracing microbial community during the production of artisanal cheeses, in order to preserve their quality and authenticity, and to select new Lactic Acid Bacteria (LAB) strains for the production of functional foods.

Droplet-based microsystems as novel assessment tools for oral microbial dynamics

The human microbiome comprises thousands of microbial species that live in and on the body and play critical roles in human health and disease. Recent findings on the interplay among members of the oral microbiome, defined by a personalized set of microorganisms, have elucidated the role of bacteria and yeasts in oral health and diseases including dental caries, halitosis, and periodontal infections. However, the majority of these studies rely on traditional culturing methods which are limited in their ability of replicating the oral microenvironment, and therefore fail to evaluate key microbial interactions in microbiome dynamics. Novel culturing methods have emerged to address this shortcoming. Here, we reviewed the potential of droplet-based microfluidics as an alternative approach for culturing microorganisms and assessing the oral microbiome dynamics. We discussed the state of the art and recent progress in the field of oral microbiology. Although at its infancy, droplet-based microtechnology presents an interesting potential for elucidating oral microbial dynamics and pathophysiology. We highlight how new findings provided by current microfluidic-based methodologies could advance the investigation of the oral microbiome. We anticipate that our work involving the droplet-based microfluidic technique with a semipermeable membrane will lay the foundations for future microbial dynamics studies and further expand the knowledge of the oral microbiome and its implication in oral health.

Isolation, Identification, and Analysis of Potential Functions of Culturable Bacteria Associated with an Invasive Gall Wasp, Leptocybe invasa

Symbioses between invasive insects and bacteria are one of the key drivers of insect invasion success. Gall-inducing insects stimulate host plants to produce galls, which affects the normal growth of plants. Leptocybe invasa Fisher et La Salle, an invasive gall-inducing wasp, mainly damages Eucalyptus plantations in Southern China, but little is known about its associated bacteria. The aim of this study was to assess the diversity of bacterial communities at different developmental stages of L. invasa and to identify possible ecological functions of the associated bacteria. Bacteria associated with L. invasa were isolated using culture-dependent methods and their taxonomic statuses were determined by sequencing the 16S rRNA gene. A total of 88 species belonging to four phyla, 27 families, and 44 genera were identified by phylogenetic analysis. The four phyla were Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes, mainly from the genera Pantoea, Enterobacter, Pseudomonas, Bacillus, Acinetobacter, Curtobacterium, Sphingobium, Klebsiella, and Rhizobium. Among them, 72 species were isolated in the insect gall stage and 46 species were isolated from the adult stage. The most abundant bacterial species were γ-Proteobacteria. We found significant differences in total bacterial counts and community compositions at different developmental stages, and identified possible ecological roles of L. invasa-associated bacteria. This study is the first to systematically investigate the associated bacteria of L. invasa using culture-dependent methods, and provides a reference for other gall-inducing insects and associated bacteria.

Microbiota identified from preserved Anopheles

Background

Mosquito species from the Anopheles gambiae complex and the Anopheles funestus group are dominant African malaria vectors. Mosquito microbiota play vital roles in physiology and vector competence. Recent research has focused on investigating the mosquito microbiota, especially in wild populations. Wild mosquitoes are preserved and transported to a laboratory for analyses. Thus far, microbial characterization post-preservation has been investigated in only Aedes vexans and Culex pipiens. Investigating the efficacy of cost-effective preservatives has also been limited to AllProtect reagent, ethanol and nucleic acid preservation buffer. This study characterized the microbiota of African Anopheles vectors: Anopheles arabiensis (member of the An. gambiae complex) and An. funestus (member of the An. funestus group), preserved on silica desiccant and RNAlater^® solution.

Methods

Microbial composition and diversity were characterized using culture-dependent (midgut dissections, culturomics, MALDI-TOF MS) and culture-independent techniques (abdominal dissections, DNA extraction, next-generation sequencing) from laboratory (colonized) and field-collected mosquitoes. Colonized mosquitoes were either fresh (non-preserved) or preserved for 4 and 12 weeks on silica or in RNAlater^®. Microbiota were also characterized from field-collected An. arabiensis preserved on silica for 8, 12 and 16 weeks.

Results

Elizabethkingia anophelis and Serratia oryzae were common between both vector species, while Enterobacter cloacae and Staphylococcus epidermidis were specific to females and males, respectively. Microbial diversity was not influenced by sex, condition (fresh or preserved), preservative, or preservation time-period; however, the type of bacterial identification technique affected all microbial diversity indices.

Conclusions

This study broadly characterized the microbiota of An. arabiensis and An. funestus. Silica- and RNAlater^®-preservation were appropriate when paired with culture-dependent and culture-independent techniques, respectively. These results broaden the selection of cost-effective methods available for handling vector samples for downstream microbial analyses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12936-021-03754-7.

Recent advances in cultivation-independent molecular-based techniques for the characterization of vaginal eubiosis and dysbiosis

“The bacterial vaginosis syndrome” has significant adverse effects for women and babies, including preterm birth and increased risk of acquisition of sexually transmitted infections and HIV. Currently, the gold standard for diagnosis is Gram stain microscopy of vaginal secretions, which is not readily available, is somewhat subjective, and does not differentiate between the likely different subtypes of vaginal dysbioses that may have different etiologies, microbiology, responses to antibiotics, and phenotypic outcomes. With new information from molecular-based, cultivation-independent studies, there is increasing interest in the use of molecular techniques for the diagnosis of bacterial vaginosis. We reviewed the current evidence on and the rationale behind the use of molecular techniques for the diagnosis of bacterial vaginosis. We found a number of commercially available molecular diagnostic tests, a few of which have US Food and Drug Administration (FDA) and/or Conformité Européenne in vitro diagnostic (CE-IVD) approval, and we have compared their performance with respect to sensitivities and specificities. Molecular-based tests have the advantage of objectivity, quantification, detection of fastidious organisms, and validity for self-obtained vaginal swabs. The performance of the molecular tests against standard microscopy is impressive, but further education of users on interpretation is needed. Bacterial vaginosis is the major cause of vaginal dysbiosis and should be recognized for the threat it is to women’s genital tract health. Quantitative assessment of microbial abundance, the diversity of other organisms present, specific primers for gene sequence regions, and clades and biovars of target microbes should be recognized and incorporated into future molecular diagnostic tests to better differentiate between vaginal eubiosis and dysbiosis.

Vaginal Microbiota Is Stable throughout the Estrous Cycle in Arabian Maress

Lactic acid bacteria (LAB) dominate human vaginal microbiota and inhibit pathogen proliferation. In other mammals, LAB do not dominate vaginal microbiota, however shifts of dominant microorganisms occur during ovarian cycle. The study objectives were to characterize equine vaginal microbiota in mares by culture-dependent and independent methods and to describe its variation in estrus and diestrus. Vaginal swabs from 8 healthy adult Arabian mares were obtained in estrus and diestrus. For culture-dependent processing, bacteria were isolated on Columbia blood agar (BA) and Man Rogosa Sharpe (MRS) agar. LAB comprised only 2% of total bacterial isolates and were not related to ovarian phases. For culture-independent processing, V3/V4 variable regions of the 16S ribosomal RNA gene were amplified and sequenced using Illumina Miseq. The diversity and composition of the vaginal microbiota did not change during the estrous cycle. Core equine vaginal microbiome consisted of Firmicutes, Bacteroidetes, Proteobacteria and Actinobacteria at the phylum level. At the genus level it was defined by Porphyromonas, Campylobacter, Arcanobacterium, Corynebacterium, Streptococcus, Fusobacterium, uncultured Kiritimatiaellae and Akkermansia. Lactobacillus comprised only 0.18% of the taxonomic composition in estrus and 0.37% in diestrus. No differences in the relative abundance of the most abundant phylum or genera were observed between estrus and diestrus samples.

Mechanistic insights into the action of probiotics against bacterial vaginosis and its mediated preterm birth: An overview

The human body is a reservoir of numerous micro-creatures; whose role is substantial and indispensable in the overall development of human beings. The advances in omic approaches have offered powerful means to decipher the core microbiome and metabolome diversities in a specific organ system. The establishment of lactobacilli in the female reproductive tract is thought to be a paramount prerequisite that maintains homeostatic conditions for a sustainable and healthy pregnancy. Nevertheless, a plethora of such Lactobacillus strains of vaginal source revealed probiotic phenotypes. The plummeting in the occurrence of lactobacilli in the vaginal ecosystem is associated with several adverse pregnancy outcomes (APOs). One such pathological condition is "Bacterial Vaginosis" (BV), a pathogen dominated gynecological threat. In this scenario, the ascending traffic of notorious Gram-negative/variable BV pathogens to the uterus is one of the proposed pathways that give rise to inflammation-related APOs like preterm birth. Since antibiotic resistance is aggravating among urogenital pathogens, the probiotics intervention remains one of the alternative biotherapeutic strategies to overcome BV and its associated APOs. Perhaps, the increased inclination towards the safer and natural biotherapeutic strategies rather than pharmaceutical drugs for maintaining gestational and reproductive health resulted in the use of probiotics in pregnancy diets. In this context, the current review is an attempt to highlight the microbiome and metabolites signatures of BV and non-BV vaginal ecosystem, inflammation or infection-related preterm birth, host-microbial interactions, role and effectiveness of probiotics to fight against aforesaid diseased conditions.

Characterization of microbial communities in ethanol biorefineries

Bacterial contamination of corn-based ethanol biorefineries can reduce their efficiency and hence increase their carbon footprint. To enhance our understanding of these bacterial contaminants, we temporally sampled four biorefineries in the Midwestern USA that suffered from chronic contamination and characterized their microbiomes using both 16S rRNA sequencing and shotgun metagenomics. These microbiotas were determined to be relatively simple, with 13 operational taxonomic units (OTUs) accounting for 90% of the bacterial population. They were dominated by Firmicutes (89%), with Lactobacillus comprising 80% of the OTUs from this phylum. Shotgun metagenomics confirmed our 16S rRNA data and allowed us to characterize bacterial succession at the species level, with the results of this analysis being that Lb. helveticus was the dominant contaminant in this fermentation. Taken together, these results provide insights into the microbiome of ethanol biorefineries and identifies a species likely to be commonly responsible for chronic contamination of these facilities.

Role for the mammalian female reproductive tract microbiome in pregnancy outcomes

Since the discovery of the microbiome in humans, it has been studied in many mammalian species. Different microbiological communities with variable richness and diversity have been found among these species in distinct areas of the reproductive tract. Human studies have shown that the composition of the microbiome is dependent on body site and several host-related factors. Furthermore, specific phyla have been identified among the different species and within distinct areas of the female reproductive tract, but a "core" microbiome of the female reproductive tract has not been defined in any species. Moreover, the function of the microbiome in the reproductive tract is not yet fully understood. However, it has been suggested that a change in diversity of the microbiome and the presence or absence of specific microbial species might be useful indicators of pregnancy outcomes. Increased comprehensive knowledge of the microbiological communities in the female reproductive tract is needed since adverse outcomes represent a significant problem to many species, including livestock, exotic or endangered species, and humans. To the authors' knowledge, a review combining current female reproductive tract microbiome data among different mammalian species has not been published yet. Herein is a comprehensive review of what is known in the field of the female reproductive microbiome and how it correlates with reproductive success or failure in mammals. Further studies may lead to optimization of therapies in the treatment of reproductive tract infections and pregnancy failure, and may create opportunities for novel approaches for improving reproductive efficiency in animals and people.

Assessment and characterization of the bacterial community structure in advanced activated sludge systems

The present study is aimed to assess and characterize the structure of bacterial community in advanced activated sludge systems. In particular, activated sludge samples were collected from an Integrated Fixed-film Activated Sludge - Membrane Bioreactor pilot plant under a University of Cape Town configuration with in-series anaerobic (Noair)/anoxic (Anox)/aerobic (Oxy) reactors - and further analyzed. The achieved results - based on Next Generation Sequencing (NGS) of 16S rDNA amplicons - revealed that the bacterial biofilm (bf) communities on plastic carriers of Oxy and Anox reactors had a greater diversity compared to suspended (sp) bacterial flocs of Oxy, Anox and Noair. Indeed, the Shannon diversity indices of both biofilm communities were higher than those of suspended growth samples (Oxy-bf = 4.1 and Anox-bf = 4.2 vs. Oxy-sp = 3.4, Anox-sp = 3.5 and Noair-sp = 3.4). The most striking differences have been reported in Rhodobacteraceae being more abundant in biofilm specimens than in suspended biomass samples. The vast majority of the identified bacteria differs from those obtained by culture dependent method, thus suggesting that NGS-based method is really suitable to analyze the bacterial community composition, even in advanced systems for wastewater treatment.

Anaerobic Process for Bioenergy Recovery From Dairy Waste: Meta-Analysis and Enumeration of Microbial Community Related to Intermediates Production

Dairy wastes are widely studied for the hydrogen and methane production, otherwise the changes in microbial communities related to intermediate valuable products was not deeply investigated. Culture independent techniques are useful tools for exploring microbial communities in engineered system having new insights into their structure and function as well as potential industrial application. The deep knowledge of the microbiota involved in the anaerobic process of specific waste and by-products represents an essential step to better understand the entire process and the relation of each microbial population with biochemical intermediates and final products. Therefore, this study investigated the microbial communities involved in the laboratory-scale anaerobic digestion of a mixture of mozzarella cheese whey and buttermilk amended with 5% w/v of industrial animal manure pellets. Culture-independent methods by employing high-throughput sequencing and microbial enumerations highlighted that lactic acid bacteria, such as Lactobacillaceae and Streptococcaceae dominated the beginning of the process until about day 14 when a relevant increase in hydrogen production (more than 10 ml H₂ gVS^-1 from days 13 to 14) was observed. Furthermore, during incubation a gradual decrease of lactic acid bacteria was detected with a simultaneous increase of Clostridia, such as Clostridiaceae and Tissierellaceae families. Moreover, archaeal populations in the biosystem were strongly related to inoculum since the non-inoculated samples of the dairy waste mixture had a relative abundance of archaea less than 0.1%; whereas, in the inoculated samples of the same mixture several archaeal genera were identified. Among methanogenic archaea, Methanoculleus was the dominant genus during all the process especially when the methane production occurred, and its relative abundance increased up to 99% at the end of the incubation time highlighting that methane was formed from dairy wastes primarily by the hydrogenotrophic pathway in the reactors.

Description of three new Peptoniphilus species cultured in the vaginal fluid of a woman diagnosed with bacterial vaginosis: Peptoniphilus pacaensis sp. nov., Peptoniphilus raoultii sp. nov., and Peptoniphilus vaginalis sp. nov

Three previously unidentified Gram‐positive anaerobic coccoid bacteria, strains KhD‐2^T, KHD4^T, and Kh‐D5^T, isolated from a vaginal swab, were characterized using the taxonogenomics concept. The phylogenic analysis, phenotypic characteristics, and genotypic data presented in this report attest that these three bacteria are distinct from previously known bacterial species with standing in nomenclature and represent three new Peptoniphilus species. Strain KhD‐2^T is most closely related to Peptoniphilus sp. DNF00840 and Peptoniphilus harei (99.7% and 98.2% identity, respectively); strain KHD4^T to Peptoniphilus lacrimalis (96%) and strain Kh‐D5^T to Peptoniphilus coxii (97.2%). Strains KhD‐2^T, KHD4^T, and Kh‐D5^TDNA G+C contents are, respectively, 34.23%, 31.87%, and 49.38%; their major fatty acid was C_16:0 (41.6%, 32.0%, and 36.4%, respectively). We propose that strains KhD‐2^T (=CSUR P0125 = DSM 101742), KHD4^T (=CSUR P0110 = CECT 9308), and Kh‐D5^T (=CSUR P2271 = DSM 101839) be the type strains of the new species for which the names Peptoniphilus vaginalis sp. nov., Peptoniphilus raoultii sp. nov., and Peptoniphilu pacaensis sp. nov., are proposed, respectively.

Vaginal microbiota and susceptibility to HIV

: Bacterial vaginosis, characterized by the replacement of the Lactobacillus-dominant microbiota with anaerobic bacteria and facultative Gram-negative rods, has been associated with adverse reproductive health outcomes including HIV acquisition. With the advent of newer molecular techniques, the vaginal microbiota can be investigated in more detail and the association with HIV examined more thoroughly. This review examines recent evidence suggesting that vaginal dysbiosis with increased microbial diversity, specific vaginal bacterial communities, and the presence and concentrations of some individual bacterial species, may increase HIV susceptibility. Potential mechanisms through which vaginal microbiota could impact HIV susceptibility are discussed. On the basis of the available data, this review finds that there is a modest, but growing, body of evidence linking vaginal microbiota to HIV susceptibility in women. The evidence could be strengthened through two main pathways. First, laboratory studies such as ex-vivo or animal experiments are needed to move from plausible mechanisms towards proven mechanisms that explain an effect of the vaginal microbiota on HIV susceptibility. Second, experimental evidence could directly test the hypothesis that sustaining optimal microbiota reduces HIV risk, though there are important obstacles to conducting such studies. Finally, this review examines strong evidence from a recent publication suggesting that deviations from an optimal vaginal microbiome, and particularly the presence of some bacterial communities with high relative abundance of Gardnerella vaginalis, reduces the efficacy of vaginal tenofovir-based microbicides.

Microbiota changes impact on sexually transmitted infections and the development of pelvic inflammatory disease

The integrity of the human urogenital microbiome is crucial for women's health and well-being. An imbalance of the urogenital microbiota increases the risk for sexually transmitted infections. In this review, we discuss the microbiota composition of the female urogenital tract and its role in protecting from sexually transmitted infections and the emergence of pelvic inflammatory disease.