Effects of vaginal lactobacilli in Chlamydia trachomatis infection

Anti-chlamydial activity of vaginal fluids: new evidence from an in vitro model

Introduction

We assessed the in vitro anti-chlamydial activity of fresh vaginal secretions, deciphering the microbial and metabolic components able to counteract Chlamydia trachomatis viability.

Methods

Forty vaginal samples were collected from a group of reproductive-aged women and their anti-chlamydial activity was evaluated by inhibition experiments. Each sample underwent 16S rRNA metabarcoding sequencing to determine the bacterial composition, as well as 1H-NMR spectroscopy to detect and quantify the presence of vaginal metabolites.

Results

Samples characterized by a high anti-chlamydial activity were enriched in Lactobacillus, especially Lactobacillus crispatus and Lactobacillus iners, while not-active samples exhibited a significant reduction of lactobacilli, along with higher relative abundances of Streptococcus and Olegusella. Lactobacillus gasseri showed an opposite behavior compared to L. crispatus, being more prevalent in not-active vaginal samples. Higher concentrations of several amino acids (i.e., isoleucine, leucine, and aspartate; positively correlated to the abundance of L. crispatus and L. jensenii) lactate, and 4-aminobutyrate were the most significant metabolic fingerprints of highly active samples. Acetate and formate concentrations, on the other hand, were related to the abundances of a group of anaerobic opportunistic bacteria (including Prevotella, Dialister, Olegusella, Peptostreptococcus, Peptoniphilus, Finegoldia and Anaerococcus). Finally, glucose, correlated to Streptococcus, Lachnospira and Alloscardovia genera, emerged as a key molecule of the vaginal environment: indeed, the anti-chlamydial effect of vaginal fluids decreased as glucose concentrations increased.

Discussion

These findings could pave the way for novel strategies in the prevention and treatment of chlamydial urogenital infections, such as lactobacilli probiotic formulations or lactobacilli-derived postbiotics.

Genital tract microbiota composition profiles and use of prebiotics and probiotics in gynaecological cancer prevention: review of the current evidence, the European Society of Gynaecological Oncology prevention committee statement

Female genital tract (FGT) microbiota has been associated with the development of gynaecological cancers. Thus, the possibility of whether manipulation of the FGT microbiota can help in the prevention of disease should be investigated. Various prebiotics, probiotics, and other non-clinician prescribed agents have been reported to have therapeutic effects in cervical disease. Numerous studies have reported an association between human papillomavirus infection and subsequent cervical dysplasia and a decrease in the abundance of Lactobacillus species. A continuum of microbiota composition is observed from the vagina to the upper parts of the FGT, but no evidence suggests that manipulation of the vaginal microbiota can help to modify the composition of other FGT compartments. Although prebiotics and probiotics have been reported to be beneficial, the studies are small and of varying design, and high-quality evidence to support their use is lacking. Currently, no studies have examined these therapeutics in other gynaecological malignancies. Thus, recommendation of probiotics, prebiotics, or other over-the-counter supplements for the prevention of gynaecological cancers warrants larger, well designed studies.

Contributions of diverse models of the female reproductive tract to the study of Chlamydia trachomatis-host interactions

Chlamydia trachomatis is a common cause of sexually transmitted infections in humans with devastating sequelae. Understanding of disease on all scales, from molecular details to the immunology underlying pathology, is essential for identifying new ways of preventing and treating chlamydia. Infection models of various complexity are essential to understand all aspects of chlamydia pathogenesis. Cell culture systems allow for research into molecular details of infection, including characterization of the unique biphasic Chlamydia developmental cycle and the role of type-III-secreted effectors in modifying the host environment to allow for infection. Multicell type and organoid culture provide means to investigate how cells other than the infected cells contribute to the control of infection. Emerging comprehensive three-dimensional biomimetic systems may fill an important gap in current models to provide information on complex phenotypes that cannot be modeled in simpler in vitro models.

Imbalance of Vaginal Microbiota and Immunity: Two Main Accomplices of Cervical Cancer in Chinese Women

Objective

To explore the correlation of female vaginal microbiota and immune factors with cervical cancer.

Methods

The distribution pattern difference of vaginal microbiota of four groups of women (cervical cancer, HPV-positive CIN, HPV-positive non-CIN, and HPV-negative groups) were compared by microbial 16S rDNA sequencing. The protein chip was used to detect the composition and changes of the immune factors in the four groups.

Results

Alpha diversity analysis demonstrated that the diversity of the vaginal microbiota was increased as the disease develops. Among those bacteria abundant in the vaginal microbiota, Lactobacillus, Prevotella, and Gardnerella dominate at the genus level of vaginal flora. Compared with the HPV-negative group, the differentially dominant bacteria, such as Prevotella, Ralstonia, Gardnerella and Sneathia, are enriched in the cervical cancer group. Likewise, Gardnerella, Prevotella, and Sneathia are more in the HPV-positive CIN group, while Gardnerella and Prevotella in the HPV-positive non-CIN group, respectively. In contrast, Lactobacillus and Atopobium are dominant in the HPV-negative group (LDA>4log10). The concentration of inflammatory immune factors IP-10 and VEGF-A were increased in the cervical cancer group (P < 0.05), compared with other groups.

Conclusion

The occurrence of cervical cancer is related to an increase of vaginal microbiota diversity and up-regulation of inflammatory immune factor proteins. The abundance of Lactobacillus was decreased while the one of Prevotella and Gardnerella were increased in the cervical cancer group, compared with other three groups. Moreover, the IP-10 and VEGF-A were also increased in the cervical cancer group. Thus, evaluation of changes in the vaginal microbiota and these two immune factor levels might be a potential non-invasive and simple method to predict cervical cancer. Furthermore, it is significant to adjust and restore the balance of vaginal microbiota and maintain normal immune function in preventing and treating cervical cancer.

Safety, tolerability, and acceptability of Lactobacillus crispatus CTV-05 (LACTIN-V) in pregnant women at high-risk of preterm birth

The vaginal microbiota is a determinant for the risk of preterm birth (PTB). Dominance of the vaginal niche by Lactobacillus crispatus associates with term delivery. This is the first observational clinical study of live vaginal biotherapeutics (Lactobacillus crispatus CTV-05 (LACTIN-V)) in pregnant women at high-risk of PTB. The primary aim was to explore safety, tolerability and acceptability of LACTIN-V in pregnancy. Women were offered a course of LACTIN-V at 14 weeks gestation for five consecutive days followed by weekly administration for six weeks. Participants were followed up at 15, 18-, 20-, 28- and 36-weeks' gestation and at delivery for assessment of adverse events, compliance and tolerability. Participants completed a questionnaire to gauge experience and acceptability. In total, 73 women were recruited, of whom eight withdrew, leaving a final cohort size of 61. Self-reported compliance to the course was high (56/60, 93%). Solicited adverse events were reported in 13 women (19%) including changes in vaginal discharge, odour, colour or consistency of urine, itching and vaginal bleeding. One unsolicited adverse event was reported as haematuria at 38 weeks gestation, but was judged to be unrelated to LACTIN-V. No serious adverse events occurred. One mild adverse event led to study withdrawal. Thirty-one women completed an experience and acceptability questionnaire. Women found LACTIN-V easy and comfortable to use and the majority (30/31, 97%) would use LACTIN-V in future pregnancies. Eight women (8/31, 26%) found the schedule of use difficult to remember. The rate of PTB <34 weeks in this cohort was 3.3% compared to 7% in a historical cohort of 2,190 women at similar background PTB risk. With satisfactory uptake and good compliance, we demonstrate that LACTIN-V is safe and accepted in pregnancy, with high tolerability. Further studies are needed to assess colonisation of Lactobacillus crispatus CTV-05 and clinical efficacy.

Commensal Lactobacilli Metabolically Contribute to Cervical Epithelial Homeostasis in a Species-Specific Manner

In reproductive-age women, the vaginal microbiome is typically dominated by one or a few Lactobacillus species, including Lactobacillus crispatus, Lactobacillus iners, Lactobacillus paragasseri, Lactobacillus mulieris, and Lactobaccillus crispatus, has been associated with optimal cervicovaginal health; however, much is still unknown about how other lactobacilli metabolically contribute to cervicovaginal health. We hypothesized that metabolites of each Lactobacillus species differ and uniquely contribute to health and homeostasis. To address this hypothesis, we utilized a human three-dimensional (3D) cervical epithelial cell model in conjunction with genomics analyses and untargeted metabolomics to determine the metabolic contributions of less-studied vaginal lactobacilli-L. iners, L. paragasseri, and L. mulieris. Our study validated that vaginal lactobacilli exhibit a close phylogenetic relationship. Genomic findings from publicly available strains and those used in our study indicated that L. iners is metabolically distinct from other species of lactobacilli, likely due to a reduced genome size. Lactobacilli and mock controls were distinguishable based on global metabolic profiles. We identified 95 significantly altered metabolites (P < 0.05) between individual lactobacilli and mock controls. Metabolites related to amino acid metabolism were shared among the lactobacilli. N-Acetylated amino acids with potential antimicrobial properties were significantly elevated in a species-specific manner. L. paragasseri and L. iners shared aromatic, but not carbohydrate-derived, lactic acid metabolites with potential antimicrobial properties that may contribute to homeostasis of the cervicovaginal environment. Additionally, L. iners uniquely altered lipid metabolism, which may be a sign of adaptation to the cervicovaginal niche. Overall, these findings further elucidate the metabolic contributions of three key vaginal Lactobacillus species in gynecological health. IMPORTANCE Lactobacillus species contribute to cervicovaginal health by their production of lactic acid and other antimicrobial compounds. Yet, much is still unknown regarding the metabolic potential of lesser-studied but common vaginal lactobacilli. Here, we used untargeted metabolomics coupled with our 3D cervical epithelial cell model to identify metabolic differences among vaginal Lactobacillus species (Lactobacillus iners, Lactobacillus paragasseri, and Lactobacillus mulieris) and how those differences related to maintaining homeostasis of the cervical epithelium. Human 3D cell models are essential tools for studying host-bacteria interactions and reducing confounding factors inherent in clinical studies. Therefore, these unique models allowed us to decipher the putative lactobacilli mechanisms that contribute to their roles in health or disease. Metabolic analyses revealed distinct profiles of each Lactobacillus species but also shared metabolic contributions associated with antimicrobial activity: amino acid metabolism, N-acetylated amino acids, and aromatic lactic acids. These patterns provided validation of metabolites associated with health in clinical studies and provided novel targets, including immunomodulatory and antimicrobial metabolites, for postbiotic therapies.

Roles of vaginal flora in human papillomavirus infection, virus persistence and clearance

Vaginal flora plays a vital role in human papillomavirus (HPV) infection and progression to cancer. To reveal a role of the vaginal flora in HPV persistence and clearance, 90 patients with HPV infection and 45 healthy individuals were enrolled in this study and their vaginal flora were analyzed. Women with HPV infection were treated with Lactobacillus in the vaginal environment as a supplement to interferon therapy. Our results indicated that patients with high risk HPV (Hr-HPV) 16/18 infection had a significantly higher alpha diversity compared with the healthy control (p < 0.01), while there was no significant difference between the non-Hr-HPV16/18 group and the controls (p > 0.05). Patients with multiple HPV infection had insignificantly higher alpha diversity compared with single HPV infection (p > 0.05). The vaginal flora of patients with HPV infection exhibited different compositions when compared to the healthy controls. The dominant bacteria with the highest prevalence in HPV-positive group were Lactobacillus iners (n = 49, 54.44%), and the top 3 dominant bacteria in the HPV-persistent group were Lactobacillus iners (n = 34, 53.13%), Sneathia amnii (n = 9, 14.06%), and Lactobacillus delbrueckii (n = 3, 4.69%). Patients with HPV clearance had significantly lower alpha diversity, and the flora pattern was also different between groups displaying HPV clearance vs. persistence. The patients with persistent HPV infection had significantly higher levels of Bacteroidaceae, Erysipelotrichaceae, Helicobacteraceae, Neisseriaceae, Streptococcaceae (family level), and Fusobacterium, Bacteroides, Neisseria, and Helicobacter (genus level) than patients who had cleared HPV (p < 0.05).

Importance

Our study revealed differences in vaginal flora patterns are associated with HPV persistence and its clearance. Interferon plus probiotics can greatly improve virus clearance in some patients. Distinguishing bacterial features associated with HPV clearance in patients would be helpful for early intervention and reverse persistent infection.

Interactions between microbiota and cervical epithelial, immune, and mucus barrier

The female reproductive tract harbours hundreds of bacterial species and produces numerous metabolites. The uterine cervix is located between the upper and lower parts of the female genital tract. It allows sperm and birth passage and hinders the upward movement of microorganisms into a relatively sterile uterus. It is also the predicted site for sexually transmitted infection (STI), such as Chlamydia, human papilloma virus (HPV), and human immunodeficiency virus (HIV). The healthy cervicovaginal microbiota maintains cervical epithelial barrier integrity and modulates the mucosal immune system. Perturbations of the microbiota composition accompany changes in microbial metabolites that induce local inflammation, damage the cervical epithelial and immune barrier, and increase susceptibility to STI infection and relative disease progression. This review examined the intimate interactions between the cervicovaginal microbiota, relative metabolites, and the cervical epithelial-, immune-, and mucus barrier, and the potent effect of the host-microbiota interaction on specific STI infection. An improved understanding of cervicovaginal microbiota regulation on cervical microenvironment homeostasis might promote advances in diagnostic and therapeutic approaches for various STI diseases.

Role of the human vaginal microbiota in the regulation of inflammation and sexually transmitted infection acquisition: Contribution of the non-human primate model to a better understanding?

The human vaginal microbiota has a central role in the regulation of the female reproductive tract (FRT) inflammation. Indeed, on one hand an optimal environment leading to a protection against sexually transmitted infections (STI) is associated with a high proportion of Lactobacillus spp. (eubiosis). On the other hand, a more diverse microbiota with a high amount of non-Lactobacillus spp. (dysbiosis) is linked to a higher local inflammation and an increased STI susceptibility. The composition of the vaginal microbiota is influenced by numerous factors that may lead to a dysbiotic environment. In this review, we first discuss how the vaginal microbiota composition affects the local inflammation with a focus on the cytokine profiles, the immune cell recruitment/phenotype and a large part devoted on the interactions between the vaginal microbiota and the neutrophils. Secondly, we analyze the interplay between STI and the vaginal microbiota and describe several mechanisms of action of the vaginal microbiota. Finally, the input of the NHP model in research focusing on the FRT health including vaginal microbiota or STI acquisition/control and treatment is discussed.

Cervical Microbiome in Women Infected with HPV16 and High-Risk HPVs

Human papillomavirus type 16 (HPV16) and/or high-risk (Hr-) HPV are the main causes of cervical cancer. Another element that may contribute to the development of cervical cancer is the microbiota. To date, no study has investigated the entire cervical microbiome, which consists of bacteria, fungi, and viruses. In this study, cervical samples with different histopathology (CIN1, CIN2, and CIN3), with or without HPV16 and Hr-HPVs infection, were enrolled. From bacterial community analysis, 115 bacterial species were found and separated into 2 distinct categories based on Lactobacillus abundance: Lactobacilli-dominated (LD) and non-Lactobacilli-dominated (NLD) groups. The LD group had significantly less bacterial diversity than the NLD group. In addition, the variety of bacteria was contingent on the prevalence of HPV infection. Among distinct histological groups, an abundance of L. iners (>60% of total Lactobacillus spp.) was discovered in both groups. A few fungi, e.g., C. albicans, were identified in the fungal community. The viral community analysis revealed that the presence of HPV considerably reduced the diversity of human viruses. Taken together, when we analyzed all our results collectively, we discovered that HPV infection was a significant determinant in the diversity of bacteria and human viruses in the cervix.

Lactic acid bacteria: prominent player in the fight against human pathogens

INTRODUCTION

The human microbiome is a unique repository of diverse bacteria. Over 1000 microbial species reside in the human gut, which predominantly influences the host's internal environment and plays a significant role in host health. Lactic acid bacteria have long been employed for multiple purposes, ranging from food to medicines. Lactobacilli, which are often used in commercial food fermentation, have improved to the point that they might be helpful in medical applications.

AREAS COVERED

This review summarises various clinical and experimental evidence on efficacy of lactobacilli in treating a wide range of infections. Both laboratory based and clinical studies have been discussed.

EXPERT OPINION

Lactobacilli are widely accepted as safe biological treatments and host immune modulators (GRAS- Generally regarded as safe) by the US Food and Drug Administration and Qualified Presumption of Safety. Understanding the molecular mechanisms of lactobacilli in the treatment and pathogenicity of bacterial infections can help with the prediction and development of innovative therapeutics aimed at pathogens which have gained resistance to antimicrobials. To formulate effective lactobacilli based therapy significant research on the effectiveness of different lactobacilli strains and its association with demographic distribution is required. Also, the side effects of such therapy needs to be evaluated.

Determination of phage load and administration time in simulated occurrences of antibacterial treatments

The use of phages as antibacterials is becoming more and more common in Western countries. However, a successful phage-derived antibacterial treatment needs to account for additional features such as the loss of infective virions and the multiplication of the hosts. The parameters critical inoculation size (V F ) and failure threshold time (T F ) have been introduced to assure that the viral dose (V ϕ) and administration time (T ϕ) would lead to the extinction of the targeted bacteria. The problem with the definition of V F and T F is that they are non-linear equations with two unknowns; thus, obtaining their explicit values is cumbersome and not unique. The current study used machine learning to determine V F and T F for an effective antibacterial treatment. Within these ranges, a Pareto optimal solution of a multi-criterial optimization problem (MCOP) provided a pair of V ϕ and T ϕ to facilitate the user's work. The algorithm was tested on a series of in silico microbial consortia that described the outgrowth of a species at high cell density by another species initially present at low concentration. The results demonstrated that the MCOP-derived pairs of V ϕ and T ϕ could effectively wipe out the bacterial target within the context of the simulation. The present study also introduced the concept of mediated phage therapy, where targeting booster bacteria might decrease the virulence of a pathogen immune to phagial infection and highlighted the importance of microbial competition in attaining a successful antibacterial treatment. In summary, the present work developed a novel method for investigating phage/bacteria interactions that can help increase the effectiveness of the application of phages as antibacterials and ease the work of microbiologists.

Microbiome-metabolome analysis reveals cervical lesion alterations

Cervical cancer (CC) continues to be one of the most common cancers among females worldwide. It takes a few years or even decades for CC to arise in a minority of women with cervical precancers. An increasing corpus of studies today indicates that local microecology and carcinogenesis are intimately related. To investigate the changes in cericovaginal microecology with the development of cervical cancer, we performed 16S rDNA sequencing and metabolomic analysis in cericovaginal fluid from 10 LSIL patients, 10 HSIL patients, 10 CC patients and 10 healthy controls to reveal the differential flora and metabolites during cervical carcinogenesis. Carcinogenesis is associated with alterations in microbiome diversity, individual taxa, and functions with notable changes in Lactobacillus, Prevotella and Aquabacterium, as well as in cervicovaginal metabolites that correlate with cervicovaginal microbial patterns. Increased bacterial diversity and a decline in the relative abundance of Lactobacillus, the dominant species in the cericovaginal flora, are observed when cervical lesions advance. According to KEGG pathway enrichment analysis, lipids and organic acids change as cervical cancer progresses, and the phenylalanine, tyrosine, and tryptophan biosynthesis pathway is essential for the development of cervical cancer. Our results reveal that microbic and metabolomic profiling is capable of distinguishing CC from precancer and highlights potential biomarkers for the early detection of cervical dysplasia. These differential microorganisms and metabolites are expected to become a potential tool to assist in the diagnosis of cervical cancer.

Cervicovaginal microbiota significantly changed for HPV-positive women with high-grade squamous intraepithelial lesion

Lower female genital tract is colonized by a variety of microbes (cervicovaginal microbiota, CVM) which associate with the risk of genital infection. This study characterized CVM for 149 Chinese women with different status of human papillomavirus (HPV) infection and squamous intraepithelial lesion (SIL): no HPV infection (HPV-), HPV infection without significant SIL (HPV+NoSIL), HPV infection with low-grade SIL (HPV+LSIL) and HPV infection with high-grade SIL (HPV+HSIL). Analysis results showed CVM has dramatically changed in HPV+HSIL group when compared to HPV+LSIL group, but it exhibited no significant differences between HPV- and HPV+NoSIL groups as well as between HPV+NoSIL and HPV+LSIL groups. In consistence, random forest analysis found more notable differences in HPV+HSIL vs HPV+LSIL comparison than in other comparisons. In addition, depletion of Lactobacillus in CVM was more to be frequently identified in SIL-positive women as compared to SIL-negative individuals. Our findings suggested that significant CVM differences occurred when SIL developed to HSIL which was caused by persistent HPV infection.

The role of vaginal microecology in the cervical cancer

AIM

To explore the role of vaginal microecology in cervical cancer, so as to increase the understanding of cervical cancer and lay a foundation for future large-sample clinical trials.

METHODS

We reviewed and summarized the literature comprehensively, and discussed the relationship between vaginal microecology and HPV infection, CIN progression and cervical cancer, as well as the potential molecular mechanism and the prospects of probiotics and prebiotics in future cancer treatments.

RESULTS

With the popularization of high-throughput sequencing technology and the development of bioinformatics analysis technology, many evidences show that the increase in the diversity of the bacterial community in the vaginal microecological environment and the decrease in the number of Lactobacilli are associated with the continuous infection of HPV and the further development of CIN, cervical cancer-related.

CONCLUSIONS

Vaginal microecological imbalance has an important impact on the occurrence and development of cervical cancer. However, the pathogenesis is not completely clear, and more high-level basic research and longitudinal clinical studies are needed to verify.

Lactobacillus Modulates Chlamydia Infectivity and Genital Tract Pathology in vitro and in vivo

Since we previously reported that women infected with chlamydia had a significant overall reduction in Lactobacillus in the vagina microbiota as compared to those uninfected individuals; the interactions between the altered Lactobacillus and Chlamydia trachomatis, on the other hand, need to be elucidated. Here, we employed both in vitro and in vivo models to evaluate the effects of this changed Lactobacillus on Chlamydia infection. We found that L. iners, L. crispatus, L. jensenii, L. salivarius, L. gasseri, L. mucosae, and L. reuteri all significantly reduced C. trachomatis infection in a dose- and time-dependent manner. The strongest anti-Chlamydia effects were found in L. crispatus (90 percent reduction), whereas the poorest was found in L. iners (50 percent reduction). D (–) lactic acid was the key component in Lactobacillus cell-free supernatants (CFS) to inactivate Chlamydia EBs, showing a positive correlation with the anti-Chlamydia activity. The effects of D (–) lactic acid were substantially attenuated by neutralizing the pH value to 7.0. In vivo, mice intravaginally inoculated with Lactobacillus mixtures (L. crispatus, L. reuteri, and L. iners at a ratio of 1:1:1), but not single Lactobacillus, after genital Chlamydia infection, significantly attenuated the levels of Chlamydia live organism shedding in both the lower genital tract and the intestinal tract, reduced cytokines production (TNF-α, IFN-γ, and IL-1β) in the vagina, and lessened upper genital tract inflammation and pathogenicity. Taken together, these data demonstrate that Lactobacillus inhibits Chlamydia infectivity both in vivo and in vitro, providing useful information for the development of Lactobacillus as adjunctive treatment in Chlamydia infection.

Extra Virgin Olive Oil-Based Green Formulations With Promising Antimicrobial Activity Against Drug-Resistant Isolates

Extra virgin olive oil (EVOO) from Olea europaea L. drupes, a cornerstone in the Mediterranean diet, is well known for its nutritional and health properties, especially for prevention of cardiovascular diseases and metabolic disorders. Traditionally, beneficial health effects have been largely attributed to the high concentration of monounsaturated fatty acids, and in recent years, these have also been related to other components including oleacein and oleocanthal. Here, we evaluated, for the first time, the antimicrobial activity of different green extra virgin olive oil-based formulations in natural deep eutectic solvents (NaDESs) emerging as powerful and biocompatible solvents. Specifically, the antimicrobial activity of the EVOO extract, as well as purified oleocanthal and oleacein in two NaDESs (choline/glycerol and choline/propylene glycol), against several drug-resistant clinical isolates and standard microbial strains has been evaluated. The main result was the inhibitory activity of the EVOO extract in choline/glycerol as well as oleacein in choline/propylene glycol toward drug-resistant Gram-positive and -negative strains. Specifically, the EVOO extract in choline/glycerol showed the highest antibacterial activity against several clinical strains of Staphylococcus aureus, whereas oleacein in choline/propylene glycol was the most effective toward various clinical strains of Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. In addition, all the formulations tested were effective against Candida spp. In conclusion, our results suggest EVOO-based formulations in NaDESs as an interesting strategy that may help in reducing the risk of development of drug resistance. Under this perspective, the usage of NaDESs for the preparation of new antimicrobial formulations may represent a promising approach.

Potential IFNγ Modulation of Inflammasome Pathway in Chlamydia trachomatis Infected Synovial Cells

Following a Chlamydia&nbsp;trachomatis infection, the host immune response is characterized by its recognition via Toll-like and Nod-like Receptors, and the subsequent activation of interferon (IFN)-γ-mediated signaling pathways. Recently, the inflammasome-mediated host cell response has emerged to play a role in the physiopathology of C. trachomatis infection. Here we investigated, for the first time, the interaction of IFN-γ and inflammasome in an in vitro model of C. trachomatis-infected primary human synovial cells. Chlamydial replication as well as the expression of caspase-1, IL-1β, as well as IL-18 and IL-6, were assayed. Our results demonstrated the inhibitory activity of IFN-γ by interfering with the inflammasome network through the downregulation of caspase-1 mRNA expression. In addition, the ability of C. trachomatis to hinder the inflammasome pathway favoring its intracellular survival within synovial cells, was observed. Overall, our data suggest a potential mechanism of immune evasion by C. trachomatis in synovial cells, that may be contested by IFN-γ.

Semen: A modulator of female genital tract inflammation and a vector for HIV-1 transmission

In order to establish productive infection in women, HIV must transverse the vaginal epithelium and gain access to local target cells. Genital inflammation contributes to the availability of HIV susceptible cells at the female genital mucosa and is associated with higher HIV transmission rates in women. Factors that contribute to genital inflammation may subsequently increase the risk of HIV infection in women. Semen is a highly immunomodulatory fluid containing several bioactive molecules with the potential to influence inflammation and immune activation at the female genital tract. In addition to its role as a vector for HIV transmission, semen induces profound mucosal changes to prime the female reproductive tract for conception. Still, most studies of mucosal immunity are conducted in the absence of semen or without considering its immune impact on the female genital tract. This review discusses the various mechanisms by which semen exposure may influence female genital inflammation and highlights the importance of routine screening for semen biomarkers in vaginal specimens to account for its impact on genital inflammation.

Culturomics Approaches Expand the Diagnostic Accuracy for Sexually Transmitted Infections

Sexually transmitted infections (STIs) are a major health concern with clinical manifestations being acknowledged to cause severe reproductive impairment. Research in infectious diseases has been centered around the known major pathogens for decades. However, we have just begun to understand that the microbiota of the female genital tract is of particular importance for disease initiation, infection progression, and pathological outcome. Thus, we are now aware that many poorly described, partially not yet known, or cultured bacteria may pave the way for an infection and/or contribute to disease severity. While sequencing-based methods are an important step in diagnosing STIs, culture-based methods are still the gold-standard method in diagnostic routine, providing the opportunity to distinguish phenotypic traits of bacteria. However, current diagnostic culture routines suffer from several limitations reducing the content of information about vaginal microbiota. A detailed characterization of microbiota-associated factors is needed to assess the impact of single-bacterial isolates from the vaginal community on vaginal health and the containment of STIs. Here we provide current concepts to enable modern culture routines and create new ideas to improve diagnostic approaches with a conjunct usage of bioinformatics. We aim to enable scientists and physicians alike to overcome long-accepted limitations in culturing bacteria of interest to the human health. Eventually, this may improve the quality of culture-based diagnostics, facilitate a research interface, and lead to a broader understanding of the role of vaginal microbiota in reproductive health and STIs.

Cervicovaginal Microbiome Factors in Clearance of Human Papillomavirus Infection

Persistent high-risk human papillomavirus (hrHPV) infection is the highest risk to cervical cancer which is the fourth most common cancer in women worldwide. A growing body of literatures demonstrate the role of cervicovaginal microbiome (CVM) in hrHPV susceptibility and clearance, suggesting the promise of CVM-targeted interventions in protecting against or eliminating HPV infection. Nevertheless, the CVM-HPV-host interactions are largely unknown. In this review, we summarize imbalanced CVM in HPV-positive women, with or without cervical diseases, and the progress of exploring CVM resources in HPV clearance. In addition, microbe- and host-microbe interactions in HPV infection and elimination are reviewed to understand the role of CVM in remission of HPV infection. Lastly, the feasibility of CVM-modulated and -derived products in promoting HPV clearance is discussed. Information in this article will provide valuable reference for researchers interested in cervical cancer prevention and therapy.

Role of Vaginal Microbiota Dysbiosis in Gynecological Diseases and the Potential Interventions

Vaginal microbiota dysbiosis, characterized by the loss of Lactobacillus dominance and increase of microbial diversity, is closely related to gynecological diseases; thus, intervention on microbiota composition is significant and promising in the treatment of gynecological diseases. Currently, antibiotics and/or probiotics are the mainstay of treatment, which show favorable therapeutic effects but also bring problems such as drug resistance and high recurrence. In this review, we discuss the role of vaginal microbiota dysbiosis in various gynecological infectious and non-infectious diseases, as well as the current and potential interventions.

Vaginal Lactobacilli and Vaginal Dysbiosis-Associated Bacteria Differently Affect Cervical Epithelial and Immune Homeostasis and Anti-Viral Defenses

Persistent infection with High Risk-Human Papilloma Viruses (HR-HPVs) is a primary cause of cervical cancer worldwide. Vaginal-dysbiosis-associated bacteria were correlated with the persistence of HR-HPVs infection and with increased cancer risk. We obtained strains of the most represented bacterial species in vaginal microbiota and evaluated their effects on the survival of cervical epithelial cells and immune homeostasis. The contribution of each species to supporting the antiviral response was also studied. Epithelial cell viability was affected by culture supernatants of most vaginal-dysbiosis bacteria, whereas Lactobacillus gasseri or Lactobacillus jensenii resulted in the best stimulus to induce interferon-γ (IFN-γ) production by human mononuclear cells from peripheral blood (PBMCs). Although vaginal-dysbiosis-associated bacteria induced the IFN-γ production, they were also optimal stimuli to interleukin-17 (IL-17) production. A positive correlation between IL-17 and IFN-γ secretion was observed in cultures of PBMCs with all vaginal-dysbiosis-associated bacteria suggesting that the adaptive immune response induced by these strains is not dominated by T_H1 differentiation with reduced availability of IFN-γ, cytokine most effective in supporting virus clearance. Based on these results, we suggest that a vaginal microbiota dominated by lactobacilli, especially by L. gasseri or L. jensenii, may be able to assist immune cells with clearing HPV infection, bypasses the viral escape and restores immune homeostasis.

Lactobacillus crispatus BC1 Biosurfactant Counteracts the Infectivity of Chlamydia trachomatis Elementary Bodies

Lactobacilli-derived biosurfactants (BS) have shown promising effects as antimicrobial molecules. Since Lactobacillus crispatus plays a crucial role in maintaining vaginal eubiosis, BS from this species could represent novel therapeutic agents to counteract sexually transmitted pathogens, such as Chlamydia trachomatis (CT). The aim of the present study was to assess the inhibitory effects of a BS produced by the vaginal strain L. crispatus BC1 on the infectivity of CT elementary bodies (EBs). For concentrations ranging between 1 and 0.5 mg/mL at 60-min contact time, L. crispatus BC1 BS displayed a highly significant anti-CT activity, with about 50% reduction of EB infectivity towards HeLa cells. To identify the components responsible for chlamydial inhibition, a panel of selected fatty acids, including those present in BS lipopeptidic structure, was tested against CT EBs. Pentadecanoic acid, myristic acid, β-hydroxy-myristic acid, and β-hydroxy-palmitic acid were able to significantly reduce EBs infectivity up to 5–0.5 µg/mL, concentrations that resulted to be non-toxic for HeLa cells. These data can contribute to the understanding of the biological role of lactobacilli in the vaginal niche, as well as to promote the application of their produced BS as an innovative and antibiotic-sparing anti-chlamydial strategy.

Bacteriocin-Like Inhibitory Substances from Probiotics as Therapeutic Agents for Candida Vulvovaginitis

Probiotics can potentially prevent and treat diseases. We examined the inhibitory activity of bacteriocin-like inhibitory substances (BLISs) from potentially probiotic lactobacilli and streptococci on Candida albicans and non-Candida albicans clinical isolates from women with vulvovaginitis. Using agar well diffusion assays, BLISs inhibited both Candida albicans and non-Candida albicans isolates. The BLIS from L. pentosus isolates had the highest anti-Candida activity (33/45; 73.3%), followed by BLISs from isolates of L. paracasei subsp. paracasei (31/45; 68.9%), L. rhamnosus I (30/45; 66.7%), L. delbrueckii subsp. lactis I (30/45; 66.7%), and S. uberis II (30/45; 66.7%). Upon characterization according to the retained activity under variable physical and chemical conditions, the BLISs showed stability against heat, pH, and surfactants, but were protease-sensitive, which suggests a proteinaceous nature of the active substances. Using crystal violet assays, the BLISs reduced the Candida biofilm biomass significantly as compared to a control group that lacked BLISs. In vivo testing of the antagonistic activity was performed using the Galleria mellonella (G. mellonella) larvae model. BLISs significantly improved survival in G. mellonella larvae treated with Candida isolates on the first, second, and seventh days, as compared to larvae inoculated with Candida only (p < 0.01). The results show that BLISs can be used as biotherapeutic agents in vulvovaginal candidiasis.

A Summary of the Fifth Annual Virology Education HIV Microbiome Workshop

In October of 2019, researchers and community members from around the world met at the NIH for the fifth annual International Workshop on Microbiome in HIV. New research was presented on the role of the microbiome on chronic inflammation and vaccine design, interactions of genetics, environment, sexual practice and HIV infection with the microbiome and the development and clinical trials of microbiome-based therapeutic approaches intended to decrease the probability of HIV acquisition/transmission or ameliorate sequelae of HIV. The keynote address by Dr. Jacques Ravel focused on his work on the vaginal microbiome and efforts to improve the analysis and resolution of microbiome data.

The Microbiome Sets the Stage for Cholera

Interactions between the eukaryotic host, microbiome members, and invading pathogens help to shape disease outcomes. Using the Drosophila model, Fast et al. identified that Vibrio cholerae acts to inhibit epithelial renewal through complex interactions between the type VI secretion system of V. cholerae and the microbial community of the fly.

The vaginal microbiota associates with the regression of untreated cervical intraepithelial neoplasia 2 lesions

Emerging evidence suggests associations between the vaginal microbiota (VMB) composition, human papillomavirus (HPV) infection, and cervical intraepithelial neoplasia (CIN); however, causal inference remains uncertain. Here, we use bacterial DNA sequencing from serially collected vaginal samples from a cohort of 87 adolescent and young women aged 16–26 years with histologically confirmed, untreated CIN2 lesions to determine whether VMB composition affects rates of regression over 24 months. We show that women with a Lactobacillus-dominant microbiome at baseline are more likely to have regressive disease at 12 months. Lactobacillus spp. depletion and presence of specific anaerobic taxa including Megasphaera, Prevotella timonensis and Gardnerella vaginalis are associated with CIN2 persistence and slower regression. These findings suggest that VMB composition may be a future useful biomarker in predicting disease outcome and tailoring surveillance, whilst it may offer rational targets for the development of new prevention and treatment strategies.

Persistent infection with human papillomavirus can lead to cervical intraepithelial neoplasia (CIN). Here, the authors profile the vaginal microbiota in a cohort of non-pregnant young women diagnosed with CIN2 and find that absence of Lactobacillusspp. and presence of a diverse population of strict anaerobes associates with a decreased regression of untreated CIN2 lesions.

Interferon-γ Possesses Anti-Microbial and Immunomodulatory Activity on a Chlamydia Trachomatis Infection Model of Primary Human Synovial Fibroblasts

Chlamydia trachomatis, an obligate intracellular pathogen, is the most common cause of bacterial sexually transmitted diseases, and it is potentially responsible for severe chronic sequelae, such as reactive arthritis. To date, details of the mechanisms by which Chlamydiae induce innate antimicrobial pathways in synovial fibroblasts, are not well characterized; therefore, herein, we investigated the effects of interferon (IFN)α, IFNβ, and IFNγ on the infection, and replication phases of the C. trachomatis developmental cycle, as well as on the induction of pattern recognition receptors (PRRs) and IFN-related pathways. To do so, we set up an in vitro chlamydial-infection model of primary human synovial cells treated with IFNs before or after the infection. We then determined the number of chlamydial inclusion forming units and inclusion size, as well as the expression of toll like receptor (TLR)2, TLR3, TLR4, cyclic GMP-AMP synthase (cGAS), stimulator of IFN gene (STING), IRF9, ISG56, and GBP1. The main result of our study is the significant inhibition of C. trachomatis infection and replication in human synovial cells following the treatment with IFNγ, whereas IFN-I proved to be ineffective. Furthermore, IFNγ greatly upregulated all the PRRs and ISGs examined. In conclusion, IFNγ exhibited a potent anti-Chlamydia activity in human synovial cells as well as the ability to induce a strong increase of innate immune pathways.

Diversity of endocervical microbiota associated with genital Chlamydia trachomatis infection and infertility among women visiting obstetrics and gynecology clinics in Malaysia

The cervical microbiota constitutes an important protective barrier against the invasion of pathogenic microorganisms. A disruption of microbiota within the cervical milieu has been suggested to be a driving factor of sexually transmitted infections. These include Chlamydia trachomatis which frequently causes serious reproductive sequelae such as infertility in women. In this study, we profiled the cervical microbial composition of a population of 70 reproductive-age Malaysian women; among which 40 (57.1%) were diagnosed with genital C. trachomatis infection, and 30 (42.8%) without C. trachomatis infection. Our findings showed a distinct compositional difference between the cervical microbiota of C. trachomatis-infected subjects and subjects without C. trachomatis infection. Specifically, significant elevations of mostly strict and facultative anaerobes such as Streptococcus, Megasphaera, Prevotella, and Veillonella in the cervical microbiota of C. trachomatis-positive women were detected. The results from the current study highlights an interaction of C. trachomatis with the environmental microbiome in the endocervical region.

The Cervicovaginal Microbiota-Host Interaction Modulates Chlamydia trachomatis Infection

The mechanism(s) by which Lactobacillus-dominated cervicovaginal microbiota provide a barrier to Chlamydia trachomatis infection remain(s) unknown. Here we evaluate the impact of different Lactobacillus spp. identified via culture-independent metataxonomic analysis of C. trachomatis-infected women on C. trachomatis infection in a three-dimensional (3D) cervical epithelium model. Lactobacillus spp. that specifically produce d(-) lactic acid were associated with long-term protection against C. trachomatis infection, consistent with reduced protection associated with Lactobacillus iners, which does not produce this isoform, and with decreased epithelial cell proliferation, consistent with the observed prolonged protective effect. Transcriptomic analysis revealed that epigenetic modifications involving histone deacetylase-controlled pathways are integral to the cross talk between host and microbiota. These results highlight a fundamental mechanism whereby the cervicovaginal microbiota modulates host functions to protect against C. trachomatis infection.IMPORTANCE The vaginal microbiota is believed to protect women against Chlamydia trachomatis, the etiologic agent of the most prevalent sexually transmitted infection (STI) in developed countries. The mechanism underlying this protection has remained elusive. Here, we reveal the comprehensive strategy by which the cervicovaginal microbiota modulates host functions to protect against chlamydial infection, thereby providing a novel conceptual mechanistic understanding. Major implications of this work are that (i) the impact of the vaginal microbiota on the epithelium should be considered in future studies of chlamydial infection and other STIs and (ii) a fundamental understanding of the cervicovaginal microbiota's role in protection against STIs may enable the development of novel microbiome-based therapeutic strategies to protect women from infection and improve vaginal and cervical health.

Chlamydia trachomatis and Chlamydia pneumoniae Interaction with the Host: Latest Advances and Future Prospective

Research in Chlamydia trachomatis and Chlamydia pneumoniae has gained new traction due to recent advances in molecular biology, namely the widespread use of the metagenomic analysis and the development of a stable genomic transformation system, resulting in a better understanding of Chlamydia pathogenesis. C. trachomatis, the leading cause of bacterial sexually transmitted diseases, is responsible of cervicitis and urethritis, and C. pneumoniae, a widespread respiratory pathogen, has long been associated with several chronic inflammatory diseases with great impact on public health. The present review summarizes the current evidence regarding the complex interplay between C. trachomatis and host defense factors in the genital micro-environment as well as the key findings in chronic inflammatory diseases associated to C. pneumoniae.

Liquid crystal delivery of ciprofloxacin to treat infections of the female reproductive tract

Infections of the female reproductive tract are a major cause of morbidity and mortality in humans, requiring significant investment to sustain treatment and representing a major challenge to health. The increasing prevalence of bacterial resistance, and an almost complete absence of new antibiotic therapies for the past five decades, mean there is a desperate need for novel approaches to the treatment of bacterial infections. Within the present study, we demonstrate the effective ex vivo treatment of bacterial infection of the female reproductive tract using a controlled-release, liquid crystal-based platform. Liquid crystal encapsulation of ciprofloxacin significantly enhanced its bactericidal efficacy and reduced cell toxicity. Liquid crystal structures are low-cost, simple to manufacture and provide a sustained-release profile of encapsulated ciprofloxacin. Treatment of Escherichia coli infected reproductive tract epithelial cells and whole organ cultures with liquid crystal encapsulated ciprofloxacin proved to be an effective strategy for reducing bacterial load and reproductive tract inflammatory responses to infection. These data suggest that such an approach could provide an efficacious treatment modality for enhancing the effectiveness of current antibiotic therapies.

Biofilm in Genital Ecosystem: A Potential Risk Factor for Chlamydia trachomatis Infection

In healthy women, the cervicovaginal microbiota is mostly populated by Lactobacillus spp., the main host defense factor of the female genital tract. In addition to Lactobacilli, other microorganisms populate the cervicovaginal microbiota, like Candida spp. and Gardnerella vaginalis. The overgrowth of Candida spp. or G. vaginalis, known as biofilm-producing microorganisms in the genital ecosystem, may lead to microbial dysbiosis that increases the risk of acquiring sexually transmitted infections, like Chlamydia trachomatis. C. trachomatis, the leading cause of bacterial sexually transmitted diseases, is still considered an important public health problem worldwide because of the impact of asymptomatic infections on long-term reproductive sequelae, including pelvic inflammatory disease and infertility. The aim of our study was to investigate the interaction between C. trachomatis and the biofilm produced by Candida albicans or Gardnerella vaginalis, evaluating whether the biofilm can harbor C. trachomatis and influence its survival as well as its infectious properties. In order to do so, we developed an in vitro coculture transwell-based biofilm model. Our findings proved, for the first time, that C. trachomatis, an intracellular obligate pathogen, survived, for up to 72 hours after exposure, inside the biofilm produced by C. albicans or G. vaginalis, retaining its infectious properties, as evidenced by the typical chlamydial inclusions observed in the cell monolayer (chlamydial inclusion-forming units at 72 h: 9255 ± 1139 and 9873 ± 1015, respectively). In conclusion, our results suggest that the biofilm related to Candida or Gardnerella genital infections may act as a reservoir of C. trachomatis and, thus, contribute to the transmission of the infection in the population as well as to its dissemination into the upper genital tract, increasing the risk of developing severe reproductive sequelae.

Vaginal pH measured in vivo: lactobacilli determine pH and lactic acid concentration

Background

Lactic acid (protonated lactate) has broad antimicrobial activity. Vaginal lactobacilli produce lactic acid, and are known to confer protection against reproductive tract infections when they are predominant in the vaginal microbiota. Using novel ex vivo methods, we showed that cervicovaginal fluid (CVF) from women with a predominantly lactobacilli-morphotype microbiota contains significantly more lactic acid than previously thought, sufficient to inactivate reproductive tract pathogens.

Here, we measured vaginal pH in vivo in 20 women with a predominantly lactobacilli-morphotype (low Nugent score) microbiota. We also investigated the in vitro production of protons (as hydrogen ions) and lactate by vaginal lactobacilli.

Results

The average vaginal pH in these women was 3.80 ± 0.20, and the average lactate concentration was 0.79% ± 0.22% w/v, with pH and lactate concentration tightly correlated for each sample. In vitro, lactobacilli cultured from these CVF samples reached an average pH of 3.92 ± 0.22, but the average lactate concentration was only 0.14% ± 0.06% w/v, approximately five-fold less than in the corresponding CVF samples. When the pH of the cultures was raised, lactate and hydrogen ion production resumed, indicating that production of lactate and hydrogen ions by vaginal lactobacilli is limited primarily by their sensitivity to hydrogen ion concentration (low pH) not lactate concentration.

Conclusions

Some vaginal lactobacilli cultures have a lower limiting pH than others, and limiting pHs in vitro showed good correlation with pHs measured in vivo. The limiting pH of the lactobacilli predominant in a woman’s vaginal microbiota seems critical in determining the concentration of antimicrobial lactic acid protecting her.

Lactobacillus crispatus BC5 Interferes With Chlamydia trachomatis Infectivity Through Integrin Modulation in Cervical Cells

Lactobacilli play a crucial role in maintaining the ecological equilibrium of the vaginal niche, preventing the colonization of exogenous microorganisms. Although many studies have discussed the mechanisms displayed by lactobacilli in counteracting several urogenital pathogens, a few data are available on the interaction between lactobacilli and Chlamydia trachomatis. This study aimed to elucidate the molecular bases of the interaction among vaginal lactobacilli, the sexually transmitted pathogen C. trachomatis and the epithelial cervical cells. We evaluated the in vitro activity of 15 Lactobacillus strains, belonging to different species (i.e., L. crispatus, L. gasseri, L. vaginalis), against C. trachomatis. In particular, we evaluated the capability of lactobacilli cells to interfere with C. trachomatis infection in HeLa cells, by exclusion assays. Lactobacilli significantly reduced C. trachomatis infectivity, being L. crispatus the most active species. Although a dose-dependent effect was noticed, a significant antagonistic activity was maintained even at lower doses. As other Gram-positive bacteria (i.e., Streptococcus agalactiae, Enterococcus faecalis, and Bacillus subtilis) failed to interfere with C. trachomatis infectivity, Lactobacillus activity proved to be specific. The potential mechanism of protection was investigated in Lactobacillus crispatus BC5, chosen as the model strain. The incubation of HeLa cell line with BC5 cells induced important modifications in the epithelial plasma membrane, by altering lipid composition and α5 integrin subunit exposure. When α5 integrin subunits were masked by a specific blocking antibody or ITGA5 gene expression was silenced, Chlamydia infection was significantly reduced. It follows that α5 integrin subunit is crucial for the pathogen infection process, and the anti-Chlamydia activity can be directly linked to membrane properties modifications in cervical cells. The three Gram-positive bacteria used as controls failed to modify the expression of α5β1 integrin. In conclusion, we identified a potential molecular mechanism at the basis of the protection exerted by L. crispatus BC5 against C. trachomatis, getting insights into the role of the cervico-vaginal microbiota for the woman’s health.

The two-sided role of the vaginal microbiome in Chlamydia trachomatis and Mycoplasma genitalium pathogenesis

Sexually transmitted infections (STI) can have major consequences for the reproductive health of women. Mycoplasma genitalium is a STI that is not as well studied but causes pelvic inflammatory disease (PID) among other complications. Another well-known STI is Chlamydia trachomatis, notorious for its capability to cause infertility. Both C. trachomatis and M. genitalium share some of the same clinical aspects. Parts of the pathogenesis of C. trachomatis and M. genitalium infections are unclear but potential factors are the microbiome and other STIs. The healthy vaginal microbiome is dominated by Lactobacillus spp; these bacteria protect the host against invading bacteria like C. trachomatis and M. genitalium by producing antibacterial compounds and providing a mechanical barrier. A dysbiosis of the vaginal microbiome is characterized by a non-Lactobacillus spp. dominated microbiome, also known as bacterial vaginosis (BV). BV and BV associated bacteria play a role in the pathogenesis of STIs such as C. trachomatis and M. genitalium. The different species of BV associated bacteria have distinct characteristics that could play a role in C. trachomatis and M. genitalium infections. Host factors should also be considered when analysing the interaction of C. trachomatis and M. genitalium and the microbiome. One important factor is the hormonal homeostasis. Oral hormonal contraception influences the vaginal milieu and could influence the infection process of STIs. Overall, this review attempts to give an overview of the pathogenesisof C. trachomatis and M. genitalium infections and the relationship between M. genitalium, C. trachomatis, and the vaginal microbiome.

Recurrent urinary tract infections in women: How promising is the use of probiotics?

Urinary tract infections (UTIs) currently rank amongst the most prevalent bacterial infections, representing a major health hazard. UTIs in females usually start as vaginal infections and ascend to the urethra and bladder. Recurrent UTIs (rUTIs) can be defined as at least three episodes of UTI in 1 year or two episodes in 6 months. Various antibiotics have been the mainstay of therapy in ameliorating the incidence of UTIs, but recurrent infections continue to afflict many women. It necessitates the exploitation of alternative antimicrobial therapy. Probiotics have been shown to be effective in varied clinical trials for long-term preventions of rUTI. Because Escherichia coli is the primary pathogen involved in UTIs which spreads from the rectum to vagina and then ascends up the sterile urinary tract, improving the gut or vaginal flora will thus impact the urinary tract. Since a healthy vaginal microbiota is mainly dominated by Lactobacillus species, in this context, exogenously administered probiotics containing Lactobacilli play a pivotal role in reducing the risk of rUTI. The concept of artificially boosting the Lactobacilli numbers through probiotic administration has long been conceived but has been recently shown to be possible. Lactobacilli may especially be useful for women with a history of recurrent, complicated UTIs or on prolonged antibiotic use. Probiotics do not cause antibiotic resistance and may offer other health benefits due to vaginal re-colonisation with Lactobacilli. However, more comprehensive research is still needed, to recommend for probiotics as an alternative to antibiotics.

Role of Lactobacilli and Lactoferrin in the Mucosal Cervicovaginal Defense

The innate defense system of the female mucosal genital tract involves a close and complex interaction among the healthy vaginal microbiota, different cells, and various proteins that protect the host from pathogens. Vaginal lactobacilli and lactoferrin represent two essential actors in the vaginal environment. Lactobacilli represent the dominant bacterial species able to prevent facultative and obligate anaerobes outnumber in vaginal microbiota maintaining healthy microbial homeostasis. Several mechanisms underlie the protection exerted by lactobacilli: competition for nutrients and tissue adherence, reduction of the vaginal pH, modulation of immunity, and production of bioactive compounds. Among bioactive factors of cervicovaginal mucosa, lactoferrin, an iron-binding cationic glycoprotein, is a multifunctional glycoprotein with antibacterial, antifungal, antiviral, and antiparasitic activities, recently emerging as an important modulator of inflammation. Lactobacilli and lactoferrin are largely under the influence of female hormones and of paracrine production of various cytokines. Lactoferrin is strongly increased in lower genital tract mucosal fluid of women affected by Neisseria gonorrheae, Chlamydia trachomatis, and Trichomonas vaginalis infections promoting both innate and adaptive immune responses. In vaginal dysbiosis characterized by low amounts of vaginal lactobacilli and increased levels of endogenous anaerobic bacteria, the increase in lactoferrin could act as an immune modulator assuming the role normally played by the healthy microbiota in vaginal mucosa. Then lactoferrin and lactobacilli may be considered as biomarkers of altered microbial homeostasis at vaginal level. Considering the shortage of effective treatments to counteract recurrent and/or antibiotic-resistant bacterial infections, the intravaginal administration of lactobacilli and lactoferrin could be a novel efficient therapeutic strategy and a valuable tool to restore mucosal immune homeostasis.

Lactobacilli-lactoferrin interplay in Chlamydia trachomatis infection

In the cervicovaginal microenvironment, lactobacilli are known to protect against genital infections and, amongst the host defence compounds, lactoferrin has recently acquired importance for its anti-microbial and anti-inflammatory properties. An abnormal genital microenvironment facilitates the acquisition of pathogens like Chlamydia trachomatis, the leading cause of bacterial sexually transmitted infections worldwide. The aim of our study is to investigate the effects of Lactobacillus crispatus, Lactobacillus brevis and bovine lactoferrin on chlamydial infection, in order to shed light on the complex interplay between host defence mechanisms and C. trachomatis. We have also evaluated the effect of these defence factors to modulate the chlamydia-mediated inflammatory state. To this purpose, we have determined the infectivity and progeny production of C. trachomatis as well as interleukin-8 and interleukin-6 synthesis. The main result of our study is that the combination of L. brevis and bovine lactoferrin is the most effective in inhibiting the early phases (adhesion and invasion) of C. trachomatis infection of cervical epithelial cells and in decreasing the levels of both cytokines. In conclusion, the interaction between L. brevis and lactoferrin seems to play a role in the protection against C. trachomatis, reducing the infection and regulating the immunomodulatory activity, thus decreasing the risk of severe complications.

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.

The Role of Skin and Orogenital Microbiota in Protective Immunity and Chronic Immune-Mediated Inflammatory Disease

The skin and orogenital mucosae, which constitute complex protective barriers against infection and injuries, are not only the first to come into contact with pathogens but are also colonized by a set of microorganisms that are essential to maintain a healthy physiological environment. Using 16S ribosomal RNA metagenomic sequencing, scientists recognized that the microorganism colonization has greater diversity and variability than previously assumed. These microorganisms, such as commensal bacteria, affect the host’s immune response against pathogens and modulate chronic inflammatory responses. Previously, a single pathogen was thought to cause a single disease, but current evidence suggests that dysbiosis of the tissue microbiota may underlie the disease status. Dysbiosis results in aberrant immune responses at the surface and furthermore, affects the systemic immune response. Hence, understanding the initial interaction between the barrier surface immune system and local microorganisms is important for understanding the overall systemic effects of the immune response. In this review, we describe current evidence for the basis of the interactions between pathogens, microbiota, and immune cells on surface barriers and offer explanations for how these interactions may lead to chronic inflammatory disorders.

Diversity of Cervical Microbiota in Asymptomatic Chlamydia trachomatis Genital Infection: A Pilot Study

Chlamydia trachomatis genital infection continues to be an important public health problem worldwide due to its increasing incidence. C. trachomatis infection can lead to severe sequelae, such as pelvic inflammatory disease, obstructive infertility, and preterm birth. Recently, it has been suggested that the cervico-vaginal microbiota may be an important defense factor toward C. trachomatis infection as well as the development of chronic sequelae. Therefore, the investigation of microbial profiles associated to chlamydial infection is of the utmost importance. Here we present a pilot study aiming to characterize, through the metagenomic analysis of sequenced 16s rRNA gene amplicons, the cervical microbiota from reproductive age women positive to C. trachomatis infection. The main finding of our study showed a marked increase in bacterial diversity in asymptomatic C. trachomatis positive women as compared to healthy controls in terms of Shannon's diversity and Shannon's evenness (P = 0.031 and P = 0.026, respectively). More importantly, the cervical microbiota from C. trachomatis positive women and from healthy controls significantly separated into two clusters in the weighted UniFrac analysis (P = 0.0027), suggesting that differences between the two groups depended entirely on the relative abundance of bacterial taxa rather than on the types of bacterial taxa present. Furthermore, C. trachomatis positive women showed an overall decrease in Lactobacillus spp. and an increase in anaerobes. These findings are part of an ongoing larger epidemiological study that will evaluate the potential role of distinct bacterial communities of the cervical microbiota in C. trachomatis infection.

Novel approaches for the taxonomic and metabolic characterization of lactobacilli: Integration of 16S rRNA gene sequencing with MALDI-TOF MS and 1H-NMR

Lactobacilli represent a wide range of bacterial species with several implications for the human host. They play a crucial role in maintaining the ecological equilibrium of different biological niches and are essential for fermented food production and probiotic formulation. Despite the consensus about the ‘health-promoting’ significance of Lactobacillus genus, its genotypic and phenotypic characterization still poses several difficulties. The aim of this study was to assess the integration of different approaches, genotypic (16S rRNA gene sequencing), proteomic (MALDI-TOF MS) and metabolomic (¹H-NMR), for the taxonomic and metabolic characterization of Lactobacillus species. For this purpose we analyzed 40 strains of various origin (intestinal, vaginal, food, probiotics), belonging to different species. The high discriminatory power of MALDI-TOF for species identification was underlined by the excellent agreement with the genotypic analysis. Indeed, MALDI-TOF allowed to correctly identify 39 out of 40 Lactobacillus strains at the species level, with an overall concordance of 97.5%. In the perspective to simplify the MALDI TOF sample preparation, especially for routine practice, we demonstrated the perfect agreement of the colony-picking from agar plates with the protein extraction protocol. ¹H-NMR analysis, applied to both culture supernatants and bacterial lysates, identified a panel of metabolites whose variations in concentration were associated with the taxonomy, but also revealed a high intra-species variability that did not allow a species-level identification. Therefore, despite not suitable for mere taxonomic purposes, metabolomics can be useful to correlate particular biological activities with taxonomy and to understand the mechanisms related to the antimicrobial effect shown by some Lactobacillus species.

Improvement of abnormal vaginal flora in Ugandan women by self-testing and short use of intravaginal antimicrobials

The vaginal composition of African women is more often lactobacillus-deficient compared to that of women from other areas around the world. Lactobacillus-deficient microflora is a known risk factor for serious health problems, such as preterm birth, cervix cancer, and entrapment of human immunodeficiency virus (HIV) and other sexually transmitted infections (STIs). The aim of this study was to assess the effect of local vaginal antibiotic or antiseptic treatment on abnormal vaginal flora (AVF), aerobic vaginitis (AV), and bacterial vaginosis (BV) among women in rural, semi-urban, and urban areas in Uganda, as compared to placebo. In a double-blind, placebo-controlled, randomized trial, 300 women presenting for outpatient routine, follow-up, or medical care at Mulago Hospital in Kampala, Uganda, were enrolled to receive 6 days of treatment with vaginal rifaximin (RFX), dequalinium chloride (DQC), or placebo if they had an increased vaginal pH of >4.5 as determined by self-testing. At initial visit and at control visit after 4 weeks, a smear was taken for blinded wet mount microscopy to determine AVF, BV, AV, and Candida severity scores. As compared to placebo, both RFX or DQC treatments dramatically diminished BV prevalence and severity from the initial to follow-up visit: the BV score declined from 2.5 to 1.6 (p < 0.0001) and from 2.5 to 1.9 (p < 0.0001), respectively. Similarly, strong improvements in the AV score were seen in both treatment regimens: moderate and severe AV declined from AV scores of 6.3 to 3.6 (p = 0.003) and from 6.6 to 4.1 (p < 0.004), respectively. Also, women with AVF (deceased or absent lactobacilli) showed similar improvements when compared with placebo. Women with normal flora and Candida at the initial visit showed less Candida after 4 weeks in the group treated with DQC (p = 0.014). Even after a short duration of intravaginal treatment with local non-absorbable antiseptics or antibiotics produced significant, lasting improvements in the vaginal microbiome composition of women with disturbed vaginal microflora. As African women have high prevalences of BV, AV, and AVF, this approach could improve their odds to prevent health-compromising complications. Further studies assessing direct health outcomes are needed to substantiate this.

The vaginal microbiota, human papillomavirus infection and cervical intraepithelial neoplasia: what do we know and where are we going next?

The vaginal microbiota plays a significant role in health and disease of the female reproductive tract. Next-generation sequencing techniques based upon the analysis of bacterial 16S rRNA genes permit in-depth study of vaginal microbial community structure to a level of detail not possible with standard culture-based microbiological techniques. The human papillomavirus (HPV) causes both cervical intraepithelial neoplasia (CIN) and cervical cancer. Although the virus is highly prevalent, only a small number of women have a persistent HPV infection and subsequently develop clinically significant disease. There is emerging evidence which leads us to conclude that increased diversity of vaginal microbiota combined with reduced relative abundance of Lactobacillus spp. is involved in HPV acquisition and persistence and the development of cervical precancer and cancer. In this review, we summarise the current literature and discuss potential mechanisms for the involvement of vaginal microbiota in the evolution of CIN and cervical cancer. The concept of manipulation of vaginal bacterial communities using pre- and probiotics is also discussed as an exciting prospect for the field of cervical pathology.

Effect of bovine lactoferrin on Chlamydia trachomatis infection and inflammation

Chlamydia trachomatis is an obligate, intracellular pathogen responsible for the most common sexually transmitted bacterial disease worldwide, causing acute and chronic infections. The acute infection is susceptible to antibiotics, whereas the chronic one needs prolonged therapies, thus increasing the risk of developing antibiotic resistance. Novel alternative therapies are needed. The intracellular development of C. trachomatis requires essential nutrients, including iron. Iron-chelating drugs inhibit C. trachomatis developmental cycle. Lactoferrin (Lf), a pleiotropic iron binding glycoprotein, could be a promising candidate against C. trachomatis infection. Similarly to the efficacy against other intracellular pathogens, bovine Lf (bLf) could both interfere with C. trachomatis entry into epithelial cells and exert an anti-inflammatory activity. In vitro and in vivo effects of bLf against C. trachomatis infectious and inflammatory process has been investigated. BLf inhibits C. trachomatis entry into host cells when incubated with cell monolayers before or at the moment of the infection and down-regulates IL-6/IL-8 synthesized by infected cells. Six out of 7 pregnant women asymptomatically infected by C. trachomatis, after 30 days of bLf intravaginal administration, were negative for C. trachomatis and showed a decrease of cervical IL-6 levels. This is the first time that the bLf protective effect against C. trachomatis infection has been demonstrated.

Natural Products for the Treatment of Chlamydiaceae Infections

Due to the global prevalence of Chlamydiae, exploring studies of diverse antichlamydial compounds is important in the development of effective treatment strategies and global infectious disease management. Chlamydiaceae is the most widely known bacterial family of the Chlamydiae order. Among the species in the family Chlamydiaceae, Chlamydia trachomatis and Chlamydia pneumoniae cause common human diseases, while Chlamydia abortus, Chlamydia psittaci, and Chlamydia suis represent zoonotic threats or are endemic in human food sources. Although chlamydial infections are currently manageable in human populations, chlamydial infections in livestock are endemic and there is significant difficulty achieving effective treatment. To combat the spread of Chlamydiaceae in humans and other hosts, improved methods for treatment and prevention of infection are needed. There exist various studies exploring the potential of natural products for developing new antichlamydial treatment modalities. Polyphenolic compounds can inhibit chlamydial growth by membrane disruption, reestablishment of host cell apoptosis, or improving host immune system detection. Fatty acids, monoglycerides, and lipids can disrupt the cell membranes of infective chlamydial elementary bodies (EBs). Peptides can disrupt the cell membranes of chlamydial EBs, and transferrins can inhibit chlamydial EBs from attachment to and permeation through the membranes of host cells. Cellular metabolites and probiotic bacteria can inhibit chlamydial infection by modulating host immune responses and directly inhibiting chlamydial growth. Finally, early stage clinical trials indicate that polyherbal formulations can be effective in treating chlamydial infections. Herein, we review an important body of literature in the field of antichlamydial research.

Lactobacillus crispatus inhibits the infectivity of Chlamydia trachomatis elementary bodies, in vitro study

Lactobacillus species dominate the vaginal microbiota of healthy reproductive-age women and protect the genitourinary tract from the attack of several infectious agents. Chlamydia trachomatis, a leading cause of sexually transmitted disease worldwide, can induce severe sequelae, i.e. pelvic inflammatory disease, infertility and ectopic pregnancy. In the present study we investigated the interference of Lactobacillus crispatus, L. gasseri and L. vaginalis, known to be dominant species in the vaginal microbiome, with the infection process of C. trachomatis. Lactobacilli exerted a strong inhibitory effect on Chlamydia infectivity mainly through the action of secreted metabolites in a concentration/pH dependent mode. Short contact times were the most effective in the inhibition, suggesting a protective role of lactobacilli in the early steps of Chlamydia infection. The best anti-Chlamydia profile was shown by L. crispatus species. In order to delineate metabolic profiles related to anti-Chlamydia activity, Lactobacillus supernatants were analysed by ¹H-NMR. Production of lactate and acidification of the vaginal environment seemed to be crucial for the activity, in addition to the consumption of the carbonate source represented by glucose. The main conclusion of this study is that high concentrations of L. crispatus inhibit infectivity of C. trachomatis in vitro.