Diverse Expression of Antimicrobial Activities Against Bacterial Vaginosis and Urinary Tract Infection Pathogens by Cervicovaginal Microbiota Strains of Lactobacillus gasseri and Lactobacillus crispatus

Vaginal microbiota and gynecological cancers: a complex and evolving relationship

The vagina hosts a community of microorganisms known as the vaginal microbiota. This community is relatively stable and straightforward, with Lactobacillus species being the most dominant members. The vaginal microbiota has various functions that are essential for maintaining human health and balance. For example, it can metabolise dietary nutrients, produce growth factors, communicate with other bacteria, modulate the immune system, and prevent the invasion of harmful pathogens. When the vaginal microbiota is disrupted, it can lead to diseases and infections. The observed disturbance is distinguished by a reduction in the prevalence of Lactobacillus and a concurrent rise in the number of other bacterial species that exhibit a higher tolerance to low oxygen levels. Gynecologic cancers are a group of cancers that affect the female reproductive organs and tissues, such as the ovaries, uterus, cervix, vagina, vulva, and endometrium. These cancers are a major global health problem for women. Understanding the complex interactions between the host and the vaginal microorganisms may provide new insights into the prevention and treatment of gynecologic cancers. This could improve the quality of life and health outcomes for women.

Cervicovaginal microbiota: a promising direction for prevention and treatment in cervical cancer

Cervical cancer is a common malignancy in women, with high incidence rate and mortality. Persistent infection of high-risk human papillomavirus (HPV) is the most important risk factor for cervical cancer and precancerous lesions. Cervicovaginal microbiota (CVM) plays an essential role in the defense of HPV infections and prevention of subsequent lesions. Dominance of Lactobacillus is the key of CVM homeostasis, which can be regulated by host, exogenous and endogenous factors. Dysbiosis of CVM, including altered microbial, metabolic, and immune signatures, can contribute to persist HPV infection, leading to cervical cancer. However, there is no evidence of the causality between CVM and cervical cancer, and the underlying mechanism remains unexplored. Considering the close correlation between CVM dysbiosis and persistent HPV infection, this review will overview CVM, its role in cervical cancer development and related mechanisms, and the prospects for therapeutic applications.

Prophylactic application of vaginal lactic acid bacteria against urogenital pathogens and its prospective use in sanitary suppositories

Beneficial and pathogenic microbes coexist in the vaginal canal, where a diminishing population of lactic acid bacteria may cause recurring urogenital infections. Probiotic bacteria Lactobacillus crispatus, Lactobacillus gasseri, Lactobacillus vaginalis, and pathogenic microbes Enterococcus faecalis, Enterobacter cloacae, Shigella sp., Staphylococcus epidermidis, and Escherichia fergusonii were isolated from vaginal swabs. Lactobacillus sp. and their probiotic culture free supernatant (PCFS) inhibited the growth of the above-mentioned urogenital pathogens. L. crispatus produced both lactic acid and hydrogen peroxide, exhibiting the best antimicrobial potential against the studied pathogens. Lyophilized L. crispatus had a shelf life of 12 months and the lyophilized PCFS also retained its antibacterial property with a minimum inhibition concentration of 1 μg/μL. Carboxy-methyl cellulose-alginate, a green alternative to super-absorbent polymers, was encapsulated with L. crispatus cells. The probiotic in its encapsulated state retained its viability for 21 days, and the bead showed 30% solvent absorptive capacity. PCFS-laced non-woven fabric displayed antibacterial property with no change in its physicochemical properties. These probiotic and postbiotic formulations have excellent prophylactic potential for urogenital infections. Such formulations can be exploited as additives in sanitary suppositories to enhance vaginal health.

Mesh and layered electrospun fiber architectures as vehicles for Lactobacillus acidophilus and Lactobacillus crispatus intended for vaginal delivery

Bacterial vaginosis (BV) is a recurrent condition that affects millions of women worldwide. The use of probiotics is a promising alternative or an adjunct to traditional antibiotics for BV prevention and treatment. However, current administration regimens often require daily administration, thus contributing to low user adherence and recurrence. Here, electrospun fibers were designed to separately incorporate and sustain two lactic acid producing model organisms, Lactobacillus crispatus (L. crispatus) and Lactobacillus acidophilus (L. acidophilus). Fibers were made of polyethylene oxide and polylactic-co-glycolic acid in two different architectures, one with distinct layers and the other with co-spun components. Degradation of mesh and layered fibers was evaluated via mass loss and scanning electron microscopy. The results show that after 48 h and 6 days, cultures of mesh and layered fibers yielded as much as 108 and 109 CFU probiotic/mg fiber in total, respectively, with corresponding daily recovery on the order of 108 CFU/(mg·day). In addition, cultures of the fibers yielded lactic acid and caused a significant reduction in pH, indicating a high level of metabolic activity. The formulations did not affect vaginal keratinocyte viability or cell membrane integrity in vitro. Finally, mesh and layered probiotic fiber dosage forms demonstrated inhibition of Gardnerella, one of the most prevalent and abundant bacteria associated with BV, respectively resulting in 8- and 6.5-log decreases in Gardnerella viability in vitro after 24 h. This study provides initial proof of concept that mesh and layered electrospun fiber architectures developed as dissolving films may offer a viable alternative to daily probiotic administration.

Vaginal colonization of women after oral administration of Lactobacillus crispatus strain NTCVAG04 from the human microbiota

BACKGROUND

The genomic approach has deeply changed the microbiology perspective, mainly concerning the microbioma identification. In this regard, some microbes colonize the healthy vagina. Vaginitis is a common gynecological ailment and includes bacterial vaginosis (BV), usually caused by local dysbiosis, such as a microbiota imbalance. Lactobacilli are the most prevalent bacteria colonizing the healthy vagina, so guaranteeing local eubiosis. In particular, vaginal colonization by L. crispatus is associated with low susceptibility to BV. Therefore, probiotics, such as life bacteria providing health advantages, are a current strategy in the prevention or treatment of vaginitis, including BV. However, there is a low level of evidence that probiotics after ingestion could really colonize the vagina. In particular, no study evidenced that L. crispatus after ingestion can colonize vagina. Therefore, the current study explored the capacity of Biovaginil® (NTC, Milan, Italy) dietary supplement containing Lactobacillus crispatus NTCVAG04 and vitamin A to colonize the gut and vagina in women with a history of vaginitis/vaginosis.

METHODS

Twenty fertile females (mean age 34.0 years) were enrolled in the study. Rectal and vaginal swabs were collected at baseline and after the first and second cycle of Biovaginil®. Each cycle lasted 14 days within two consecutive menstrual periods.

RESULTS

Seven women were excluded from the analysis because the samples were technically not evaluable. One woman dropped out because of mild adverse event. At the end of the study, nine women (75%) had positive rectal swab for L. crispatus NTCVAG04, and 8 of them also had positive vaginal swab.

CONCLUSIONS

The current study provided the first evidence that L. crispatus NTCVAG04, administered by two Biovaginil® courses, colonized both the gut and vagina. Moreover, the L. crispatus NTCVAG04 strain could be considered the archetype of a new class of oral probiotics that actively colonize the vagina, and that could be called "colpobiotics."

Draft genome sequence and probiotic functional property analysis of Lactobacillus gasseri LM1065 for food industry applications

Probiotics are defined as live organisms in the host that contribute to health benefits. Lactobacillus gasseri LM1065, isolated from human breast milk, was investigated for its probiotic properties based on its genome. Draft genome map and de novo assembly were performed using the PacBio RS II system and hierarchical genome assembly process (HGAP). Probiotic properties were determined by the resistance to gastric conditions, adherence ability, enzyme production, safety assessment and mobile genetic elements. The fungistatic effect and inhibition of hyphae transition were studied using the cell-free supernatant (CFS). L. gasseri LM1065 showed high gastric pepsin tolerance and mild tolerance to bile salts. Auto-aggregation and hydrophobicity were measured to be 61.21% and 61.55%, respectively. The adherence to the human intestinal epithelial cells was measured to be 2.02%. Antibiotic-resistance genes and putative virulence genes were not predicted in the genomic analysis, and antibiotic susceptibility was satisfied by the criteria of the European Food Safety Authority. CFS showed a fungistatic effect and suppressed the tricarboxylic acid cycle in Candida albicans (29.02%). CFS also inhibited the transition to true hyphae and damaged the blastoconidia. This study demonstrates the essential properties of this novel probiotic, L. gasseri LM1065, and potential to inhibit vaginal C. albicans infection.

Lactobacillus crispatus-loaded electrospun fibers yield viable and metabolically active bacteria that kill Gardnerella in vitro

Bacterial vaginosis (BV) is a common condition that affects one-third of women worldwide. BV is characterized by low levels of healthy lactobacilli and an overgrowth of common anaerobes such as Gardnerella. Antibiotics for BV are administered orally or vaginally; however, approximately half of those treated will experience recurrence within 6 months. Lactobacillus crispatus present at high levels has been associated with positive health outcomes. To address the high recurrence rates following BV treatment, beneficial bacteria have been considered as an alternative or adjunct modality. This study aimed to establish proof-of-concept for a new long-acting delivery vehicle for L. crispatus. Here, it is shown that polyethylene oxide (PEO) fibers loaded with L. crispatus can be electrospun with poly(lactic-co-glycolic acid) (PLGA) fibers (ratio 1:1), and that this construct later releases L. crispatus as metabolically viable bacteria capable of lactic acid production and anti-Gardnerella activity. Probiotic-containing fibers were serially cultured in MRS (deMan, Rogosa, Sharpe) broth with daily media replacement and found to yield viable L. crispatus for at least 7 days. Lactic acid levels and corresponding pH values generally corresponded with levels of L. crispatus cultured from the fibers and strongly support the conclusion that fibers yield viable L. crispatus that is metabolically active. Cultures of L. crispatus-loaded fibers limited the growth of Gardnerella in a dilution-dependent manner during in vitro assays in the presence of cultured vaginal epithelial cells, demonstrating bactericidal potential. Exposure of VK2/E6E7 cells to L. crispatus-loaded fibers resulted in minimal loss of viability relative to untreated cells. Altogether, these data provide proof-of-concept for electrospun fibers as a candidate delivery vehicle for application of vaginal probiotics in a long-acting form.

The Impact of the Female Genital Microbiota on the Outcome of Assisted Reproduction Treatments

The vaginal microbiota plays a critical role in the health of the female genital tract, and its composition contributes to gynecological disorders and infertility. Lactobacilli are the dominant species in the female genital tract: their production of lactic acid, hydrogen peroxide, and bacteriocins prevents the invasion and growth of pathogenic microorganisms. Several factors such as hormonal changes, age of reproduction, sexual practices, menstrual cycle, pregnancy, and antimicrobial drugs use can cause imbalance and dysbiosis of the vaginal microbiota. This review aims to highlight the impact of the vaginal microbiota in Assisted Reproductive Technology techniques (ART) and it examines the factors that influence the vaginal microbiota, the consequences of dysbiosis, and potential interventions to restore a healthy female genital tract.

Special Issue "An Update on Lactobacillus": Editorial

As indicated in the introduction to this Special Issue, as of 2020, the original genus Lactobacillus comprised over 260 recognized species, a figure which is probably much higher now [...].

Etiology of recurrent cystitis in postmenopausal women based on vaginal microbiota and the role of Lactobacillus vaginal suppository

Background

The vaginal microbiota can be altered by uropathogenic bacteria associated with recurrent cystitis (RC), and the vaginal administration of Lactobacillus have suggested certain effects to prevent RC. The relationship between vaginal microbiota and the development of RC has not been elucidated. We aimed to clarify the etiology of RC from vaginal microbiota and importance of vaginal Lactobacillus.

Methods

Vaginal samples obtained from 39 postmenopausal women were classified into four groups: healthy controls; uncomplicated cystitis; RC; and prevention (prevented RC by Lactobacillus crispatus-containing vaginal suppositories). Principal coordinate analysis and beta-diversity analysis was used to assess 16S rRNA gene sequencing data from the vaginal microbiome.

Results

Cluster analysis divided the vaginal bacterial communities among 129 vaginal samples into three clusters (A, B, and C). Fourteen of 14 (100%) samples from the RC group and 51 of 53 (96%) samples from the prevention group were in clusters B and C, while 29 of 38 (76%) samples from the healthy group and 14 of 24 (58%) samples from the uncomplicated cystitis group were in cluster A. The principal coordinate analysis showed that plots in the uncomplicated cystitis group were similar to the healthy group, indicating a large separation between the RC group and the uncomplicated cystitis group. On beta-diversity analysis, there were significant differences between the healthy group and the uncomplicated cystitis group (p = 0.045), and between the RC group and the uncomplicated cystitis group or the healthy group (p = 0.001, p = 0.001, respectively). There were no significant differences between the RC group and the prevention group (p = 0.446). The top six taxa were as follows: Prevotella, Lactobacillus, Streptococcus, Enterobacteriaceae, Anaerococcus, and Bifidobacterium. Among patients with RC, Lactobacillus was undetectable before administration of suppositories, while the median relative abundance of Lactobacillus was 19% during administration of suppositories (p = 0.0211), reducing the average cystitis episodes per year (6.3 vs. 2.4, p = 0.0015).

Conclusion

The vaginal microbiota of postmenopausal women with RC is differed from healthy controls and uncomplicated cystitis in terms of lack of Lactobacillus and relatively dominant of Enterobacteriaceae. Vaginal administration of Lactobacillus-containing suppositories can prevent RC by stabilizing vaginal dysbiosis and causing a loss of pathogenic bacteria virulence.

ESKAPEE Pathogen Biofilm Control on Surfaces with Probiotic Lactobacillaceae and Bacillus species

Combatting the rapidly growing threat of antimicrobial resistance and reducing prevalence and transmission of ESKAPEE pathogens in healthcare settings requires innovative strategies, one of which is displacing these pathogens using beneficial microorganisms. Our review comprehensively examines the evidence of probiotic bacteria displacing ESKAPEE pathogens, with a focus on inanimate surfaces. A systematic search was conducted using the PubMed and Web of Science databases on 21 December 2021, and 143 studies were identified examining the effects of Lactobacillaceae and Bacillus spp. cells and products on the growth, colonization, and survival of ESKAPEE pathogens. While the diversity of study methods limits evidence analysis, results presented by narrative synthesis demonstrate that several species have the potential as cells or their products or supernatants to displace nosocomial infection-causing organisms in a variety of in vitro and in vivo settings. Our review aims to aid the development of new promising approaches to control pathogen biofilms in medical settings by informing researchers and policymakers about the potential of probiotics to combat nosocomial infections. More targeted studies are needed to assess safety and efficacy of different probiotic formulations, followed by large-scale studies to assess utility in infection control and medical practice.

Covariates of vaginal microbiota and pro-inflammatory cytokine levels in women of reproductive age

This study aimed to assess the correlation between covariates of the vaginal microbiota and local levels of proinflammatory cytokines in women of reproductive age presenting four molecularly defined bacterial community-state types (CSTs). We enrolled 133 non-pregnant women who attended primary care health clinics for routine Pap-testing. Molecular profiling of vaginal microbiota was performed by V3-V4 16S rRNA sequencing. The covariates of vaginal microbiota included were: vaginal pH, total bacterial cell count, diversity (Shannon index), -richness and dominant taxa abundances. Levels of interleukin (IL)-1β, IL-6, IL-8, and tumour necrosis factor (TNF-α) were measured by enzyme-linked immunosorbent assays in supernatants of cervicovaginal fluids. Nonparametric Kruskal-Wallis test was used to compare microbiota covariates and cytokines among different CSTs. Spearman's tests were performed to assess correlations across the measured parameters. A total of 96 (72.2%) participants had CSTs dominated by Lactobacillus spp. (Lactobacillus crispatus CST I, n=38; Lactobacillus gasseri CST II, n=20; and Lactobacillus iners CST III, n=38). A total of 37 (27.8%) presented the Lactobacillus-depleted CST IV. Total bacterial count was higher in CST II (1.29E+05, 3.40E+04-6.69E+05) compared to other Lactobacillus-dominated CSTs (p=0.0003). The highest values of microbiota diversity (1.85; 0.23-2.68) and richness (27.0; 5.0-37.0) were observed in CST IV (P<0.0001). Lower levels of IL-1β were observed in CST I (5.4; 0.0-3,256) when compared to CST III (51.7; 0.0-2,616) and to CST IV (56.2; 0.0-3,407) (P=0.008). Levels of IL-6 were higher in CST II (4.13; 0-131.4) than in CST IV (0.0-58.27) (P=0.02). Correlation tests showed an overall distinct profile of CST II when compared to other Lactobacillusdominated CSTs, particularly regarding the correlation between total bacterial load and cytokines (r>0.39). In conclusion, this study provides evidence of a single pro-inflammatory signature of L. gasseri-dominated microbiota in response to bacterial load. Further studies evaluating a broader range of inflammation markers are warranted.

Effects of Marinades Prepared from Food Industry By-Products on Quality and Biosafety Parameters of Lamb Meat

This study aimed to develop marinade formulas based on by-products from the dairy, berry, and fruit industries and apply them to lamb meat (LM) treatments to improve the safety and quality characteristics of the meat. To fulfil this aim, six marinade (M) formulations were created based on acid whey (AW) fermented with Lacticaseibacillus casei (Lc) and Liquorilactobacillus uvarum (Lu), either alone or combined with freeze-dried apple (AP) or blackcurrant (BC) pomace. The most appropriate fermentation times for the marinades were selected according to the lower pH values and higher viable LAB counts in the samples. Additionally, the antimicrobial activity of the selected marinades against pathogenic and opportunistic bacterial strains was tested. The characteristics of the LM were analysed after 24 and 48 h of treatment, including physicochemical, technological, and microbiological parameters, as well as overall acceptability. It was established that, after 48 h of fermentation, all of the tested marinades, except M-AWLuBC, had lactic acid bacterial counts > 8.0 log10 CFU·mL−1 and pH values < 3.74. The broadest spectra of pathogen inhibition were observed in the M-AWLuAP and M-AWLuBC marinades. The latter formulations improved the water holding capacity (WHC) and overall acceptability of the LM, while, in the LM-AWLcAP samples, histamine, cadaverine, putrescine, tryptamine, and phenylethylamine were not formed. Lastly, LM treatment with the M-AWLcAP and M-AWLuAP formulas for 48 h achieved the highest overall acceptability (9.04 and 9.43), tenderness (1.53 and 1.47 kg·cm−2) and WHC (2.95% and 3.5%) compared to the control samples.

Lactobacilli and Their Probiotic Effects in the Vagina of Reproductive Age Women

In the present narrative review, the probiotic effects of vaginal Lactobacillus spp. are described in detail, covering the importance of the differential production of lactic acid, the lactic acid D/L isoforms, the questionable in vivo effect of hydrogen peroxide, as well as bacteriocins and other core proteins produced by vaginal Lactobacillus spp. Moreover, the microbe–host interaction is explained with emphasis on the vaginal mucosa. To understand the crucial role of Lactobacillus spp. dominance in the vaginal microbiota, different dysbiotic states of the vagina are explained including bacterial vaginosis and aerobic vaginitis. Finally, this review takes on the therapeutic aspect of live lactobacilli in the context of bacterial vaginosis. Until recently, there was very low-quality evidence to suggest that any probiotic might aid in reducing vaginal infections or dysbiosis. Therefore, clinical usage or over the counter usage of probiotics was not recommended. However, recent progress has been made, moving from probiotics that are typically regulated as food supplements to so-called live biotherapeutic products that are regulated as medical drugs. Thus, recently, a phase 2b trial using a Lactobacillus crispatus strain as a therapeutic add-on to standard metronidazole showed significant reduction in the recurrence of bacterial vaginosis by 12 weeks compared to placebo. This may constitute evidence for a brighter future where the therapeutic use of lactobacilli can be harnessed to improve women’s health.

Impact of Lactobacillus crispatus-containing oral and vaginal probiotics on vaginal health: a randomised double-blind placebo controlled clinical trial

Health of reproductive tract is tightly associated with balance of microbial communities in this area. Bacterial vaginosis (BV) and vulvovaginal candidiasis (VVC) represent common disturbances of vaginal communities. Vaginal discharge due to BV or VVC is a very frequent reason for visiting gynaecologist. We aimed to evaluate the impact of the novel evidence-based probiotics on BV and VVC patients. The study group included 89 BV and 93 VVC patients (aged 18-50 years) who were recruited into randomised double-blind placebo-controlled two-arm parallel trial. The patients of each diagnosis group received oral or vaginal probiotic capsules, or placebo capsules during 3 months. A probiotic capsule contained two (DSM32717 and DSM32720, in case of BV) or three (DSM32720, DSM32718 and DSM32716, in case of VVC) Lactobacillus crispatus strains. Vaginal, intestinal and general health was monitored weekly by questionnaire. Blood analyses were done in the beginning and at the end of trial. Vaginal samples were collected monthly, microscopic and molecular analyses were performed. The study revealed that both oral and vaginal capsules reduced the signs and symptoms in BV patients. Remarkable improvement was noted in Nugent score, amount and smell of discharge, but also in itching/irritation. Consumption of vaginal probiotics significantly increased the lactobacilli counts in their vagina while mean proportion of some BV-related bacteria decreased. In VVC patients, both oral and vaginal capsules lowered the combined score of two most important symptoms, amount of discharge and itching/irritation. In conclusion, the novel formulations of evidence-based well-focused probiotic L. crispatus strains are effective against BV and VVC being suitable for both vaginal and oral administration. Clinical trial registration: ISRCTN34840624, BioMed Central.

Microbiota Ecosystem in Recurrent Cystitis and the Immunological Microenvironment of Urothelium

Urinary tract infections (UTIs) represent one of the most frequent low genital tract diseases in the female population. When UTIs occur with a frequency of at least three times per year or two times in the last six month, we speak of recurrent UTI (rUTI) and up to 70% of women will have rUTI within 1 year. It was previously thought that antibiotic resistance was principally responsible for the recurrence of UTIs, but nowadays new diagnostic technologies have shown the role of microbiota in the pathophysiology of these diseases. Much research has been conducted on the role of gut microbiome in the development of rUTI, while little is known yet about vaginal and urinary microbiome and the possible immunological and microscopical mechanisms through which they trigger symptoms. New discoveries and clinical perspectives are arising, and they all agree that a personalized, multi-modal approach, treating vaginal and urinary dysbiosis, may reduce rUTIs more successfully.

Lactobacilli, a Weapon to Counteract Pathogens through the Inhibition of Their Virulence Factors

To date, several studies have reported an alarming increase in pathogen resistance to current antibiotic therapies and treatments. Therefore, the search for effective alternatives to counter their spread and the onset of infections is becoming increasingly important.

The association of cervicovaginal Langerhans cells with clearance of human papillomavirus

Human papillomavirus (HPV) clearance is important in eliminating cervical cancer which contributes to high morbidity and mortality in women. Nevertheless, it remains largely unknown about key players in clearing pre-existing HPV infections. HPV antigens can be detected by the most important cervical antigen-presenting cells (Langerhans cells, LCs), of which the activities can be affected by cervicovaginal microbiota. In this review, we first introduce persistent HPV infections and then describe HPV-suppressed LCs activities, including but not limited to antigen uptake and presentation. Given specific transcriptional profiling of LCs in cervical epithelium, we also discuss the impact of cervicovaginal microbiota on LCs activation as well as the promise of exploring key microbial players in activating LCs and HPV-specific cellular immunity.

Protective Effect of Lactobacillus crispatus against Vaginal Colonization with Group B Streptococci in the Third Trimester of Pregnancy

Background: A normal vaginal microbiota may protect the vaginal mucosa from colonization by potentially pathogenic bacteria, including group B streptococci (GBS). The aim of this study was to investigate the association between colonization with GBS and the presence of specific vaginal microbiota isolated from vaginal swabs in the third trimester of pregnancy. Methods: A semiquantitative culture of 1860 vaginal swabs from consecutive pregnant women in their third trimester was analyzed. The dominant bacteria, including lactobacilli, were identified using MALDI-TOF mass spectrometry. An enrichment culture for GBS was performed on the swabs. GBS colonization correlated with the bacteria isolated at the same time. Results: Lactobacilluscrispatus was isolated in 27.5% of the cultures, followed by L. jensenii (13.9%), L. gasseri (12.6%), and L. iners (10.1%). The presence of lactobacilli as a group, and of L. crispatus, inversely correlated with GBS colonization (OR = 0.44 and OR = 0.5, respectively; both with p < 0.001). Other microorganisms, including Gardnerella vaginalis, mixed aerobic bacteria and yeasts, were not associated with GBS colonization. Conclusions: Lactobacilli, especially L. crispatus, may prevent GBS colonization in pregnancy. Maintaining a normal vaginal microbiota could be an effective method for the antibiotic-free prevention of invasive GBS infections in neonates.

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.

Commensal Urinary Lactobacilli Inhibit Major Uropathogens In Vitro With Heterogeneity at Species and Strain Level

The human urinary microbiome is thought to affect the development and progression of urinary tract infections (UTI), particularly recurrent UTIs in aging populations of women. To understand the possible interactions of urinary pathogens with commensal bacteria inhabiting the aging bladder, we conducted an initial functional assessment of a representative set of urinary lactobacilli that dominate this niche in postmenopausal women. We created a repository of urinary bladder bacteria isolated via Enhanced Quantitative Urinary Culture (EQUC) from healthy postmenopausal women, as well as those with a culture-proven recurrent UTI (rUTI) diagnosis. This repository contains lactobacilli strains from eight different species. As many other lactobacilli are known to inhibit human pathogens, we hypothesized that some urinary lactobacilli will have similar abilities to inhibit the growth of typical uropathogens and thus, provide a link between the urinary microbiome and the predisposition to the rUTI. Therefore, we screened the urinary lactobacilli in our repository for their ability to inhibit model uropathogens in vitro. We observed that many urinary isolates strongly inhibit model strains of gram-negative Escherichia coli and Klebsiella pneumoniae but demonstrate less inhibition of gram-positive Enterococcus faecalis. The observed inhibition affected model strains of uropathogens as well as clinical and multidrug-resistant isolates of those species. Our preliminary analysis of inhibition modes suggests a combination of pH-dependent and cell-dependent inhibition. Overall, inhibition strongly varies among species and strains of urinary lactobacilli. While the strength of the inhibition is not predictive of health outcomes in this limited repository, there is a high level of species and strain diversity that warrants future detailed investigations.

Breaking Down the Barrier: The Role of Cervical Infection and Inflammation in Preterm Birth

Approximately 40% of cases of spontaneous preterm birth (sPTB) are associated with ascending intrauterine infections. The cervix serves as a physical and immunological gatekeeper, preventing the ascent of microorganisms from the vagina to the amniotic cavity. The cervix undergoes remodeling during pregnancy. It remains firm and closed from the start until the late third trimester of pregnancy and then dilates and effaces to accommodate the passage of the fetus during delivery. Remodeling proceeds appropriately and timely to maintain the pregnancy until term delivery. However, risk factors, such as acute and chronic infection and local inflammation in the cervix, may compromise cervical integrity and result in premature remodeling, predisposing to sPTB. Previous clinical studies have established bacterial (i.e., chlamydia, gonorrhea, mycoplasma, etc.) and viral infections (i.e., herpesviruses and human papillomaviruses) as risk factors of PTB. However, the exact mechanism leading to PTB is still unknown. This review focuses on: (1) the epidemiology of cervical infections in pregnant patients; (2) cellular mechanisms that may explain the association of cervical infections to premature cervical ripening and PTB; (3) endogenous defense mechanisms of the cervix that protect the uterine cavity from infection and inflammation; and (4) potential inflammatory biomarkers associated with cervical infection that can serve as prognostic markers for premature cervical ripening and PTB. This review will provide mechanistic insights on cervical functions to assist in managing cervical infections during pregnancy.

Engineering of Vaginal Lactobacilli to Express Fluorescent Proteins Enables the Analysis of Their Mixture in Nanofibers

Lactobacilli are a promising natural tool against vaginal dysbiosis and infections. However, new local delivery systems and additional knowledge about their distribution and mechanism of action would contribute to the development of effective medicine. This will be facilitated by the introduction of the techniques for effective, inexpensive, and real-time tracking of these probiotics following their release. Here, we engineered three model vaginal lactobacilli (Lactobacillus crispatus ATCC 33820, Lactobacillus gasseri ATCC 33323, and Lactobacillus jensenii ATCC 25258) and a control Lactobacillus plantarum ATCC 8014 to express fluorescent proteins with different spectral properties, including infrared fluorescent protein (IRFP), green fluorescent protein (GFP), red fluorescent protein (mCherry), and blue fluorescent protein (mTagBFP2). The expression of these fluorescent proteins differed between the Lactobacillus species and enabled quantification and discrimination between lactobacilli, with the longer wavelength fluorescent proteins showing superior resolving power. Each Lactobacillus strain was labeled with an individual fluorescent protein and incorporated into poly (ethylene oxide) nanofibers using electrospinning, as confirmed by fluorescence and scanning electron microscopy. The lactobacilli retained their fluorescence in nanofibers, as well as after nanofiber dissolution. To summarize, vaginal lactobacilli were incorporated into electrospun nanofibers to provide a potential solid vaginal delivery system, and the fluorescent proteins were introduced to distinguish between them and allow their tracking in the future probiotic-delivery studies.

The urobiome, urinary tract infections, and the need for alternative therapeutics

Improvements in bacterial culturing and DNA sequencing techniques have revealed a diverse, and hitherto unknown, urinary tract microbiome (urobiome). The potential role of this microbial community in contributing to health and disease, particularly in the context of urinary tract infections (UTIs) is of significant clinical importance. However, while several studies have confirmed the existence of a core urobiome, the role of its constituent microbes is not yet fully understood, particularly in the context of health and disease. Herein, we review the current state of the art, concluding that the urobiome represents an important component of the body's innate immune defences, and a potentially rich resource for the development of alternative treatment and control strategies for UTIs.

Phenyl-lactic acid is an active ingredientin bactericidal supernatants of Lactobacillus crispatus

Lactobacillus crispatus is a well-established probiotic, with antimicrobial activity against pathogens across several niches of the human body generally attributed to the production of bacteriostatic molecules, including hydrogen peroxide and lactic acid. Here, we show that the cell-free supernatants of clinical isolates of L. crispatus harbor robust bactericidal activity. We further identify phenyl-lactic acid as a bactericidal compound with properties and susceptibility range near-identical to that of the cell-free supernatant. As such, we hypothesize that phenyl-lactic acid is a key active ingredient in L. crispatus supernatant. IMPORTANCE Although Lactobacillus crispatus is an established commensal microbe frequently used in probiotics, its protective role in the bladder microbiome has not been clarified. We report here that some urinary isolates of L. crispatus exhibit bactericidal activity, primarily due to its ability to excrete phenyl-lactic acid into its environment. Both cell free supernatants of L. crispatus isolates and phenyl-lactic acid exhibit bactericidal activity against a wide range of pathogens, including several that are resistant to multiple antibiotics.

Variability of the response of human vaginal Lactobacillus crispatus to 17β-estradiol

We previously showed that the physiological concentration of 17β-estradiol in the vaginal environment is sufficient to affect the membrane dynamics and adhesion phenotype of the Lactobacillus crispatus strain CIP104459. However, L. crispatus is a heterogeneous species. Here, we investigated the effect of 17β-estradiol on the recently isolated L. crispatus vaginal strain V4, related to a cluster distant from CIP104459 and at the limit of being a different subspecies. Grown in the same medium, the two strains expressed a highly similar pool of proteins. However, in contrast to CIP104459, L. crispatus V4 showed high aggregation potential and 17β-estradiol promoted this phenotype. This effect was associated with large changes in cell-surface polarity and Lewis acid/base properties. In addition, we observed no effect on the membrane dynamics, contrary to CIP104459. These results can be explained by differences in the properties and organization of the S layer between the two strains. However, as for CIP104459, 17β-estradiol increased biosurfactant production of L. crispatus V4 and their adhesion to vaginal cells. This suggests that 17β-estradiol agonists would be valuable tools to favor a stable re-implantation of L. crispatus in the vaginal mucosa.

Impact of Vaginal Estrogen on the Urobiome in Postmenopausal Women With Recurrent Urinary Tract Infection

OBJECTIVE

The aim of this study was to describe effects of vaginal estrogen (VE) on the urogenital microbiome in postmenopausal women with recurrent urinary tract infections (rUTIs).

METHODS

This is a secondary analysis of 17 participants enrolled in a randomized controlled trial of VE versus placebo on urinary tract infection recurrence in postmenopausal women with rUTIs. Paired clean-catch urine samples were collected at baseline and after 6 months of VE and sequenced using 16S rRNA gene sequencing. Sequence reads were analyzed using Quantitative Insights Into Microbial Ecology 2. Changes in α diversity, β diversity, and differentially abundant genera were measured between paired baseline and 6-month samples and between those with a urinary tract infection at 6 months (failures) and those without (successes).

RESULTS

Of the 17 women, 11 were successes and 6 were failures after 6 months of VE treatment. There was a significant change in α diversity from baseline to month 6 in samples overall (Kruskal-Wallis χ2 = 3.47, P = 0.037) and in the treatment success group (Yuen T = -2.53, P = 0.035). The increase in relative abundance of Lactobacillus crispatus, Lactobacillus gasseri, and Lactobacillus iners AB-1 was correlated with month 6. A relative bloom of L. crispatus compared with L. gasseri was associated with treatment success (Kruskal-Wallis χ2 = 4.9, P = 0.0014).

CONCLUSIONS

Lactobacillus increases in the urogenital microbiome of postmenopausal women with rUTI after 6 months of VE. However, only the relative increase in L. crispatus specifically may be associated with treatment success.

Targeted Delivery of Probiotics: Perspectives on Research and Commercialization

Considering the significance of the gut microbiota on human health, there has been ever-growing research and commercial interest in various aspects of probiotic functional foods and drugs. A probiotic food requires cautious consideration in terms of strain selection, appropriate process and storage conditions, cell viability and functionality, and effective delivery at the targeted site. To address these challenges, several technologies have been explored and some of them have been adopted for industrial applicability. Encapsulation of probiotics has been recognized as an effective way to stabilize them in their dried form. By conferring a physical barrier to protect them from adverse conditions, the encapsulation approach renders direct benefits on stability, delivery, and functionality. Various techniques have been explored to encapsulate probiotics, but it is noteworthy that the encapsulation method itself influences surface morphology, viability, and survivability of probiotics. This review focuses on the need to encapsulate probiotics, trends in various encapsulation techniques, current research and challenges in targeted delivery, the market status of encapsulated probiotics, and future directions. Specific focus has been given on various in vitro methods that have been explored to better understand their delivery and performance.

Antibacterial Activity of Lactic Acid Producing Leuconostoc mesenteroides QZ1178 Against Pathogenic Gallibacterium anatis

Lactic acid bacteria (LAB) convert carbohydrates into organic acids [mainly lactic acid (LA)], which reportedly have bactericidal activities. Gallibacterium anatis is a Gram-negative bacteria which infects birds, and causes significant economic losses. In this study, we investigated the antibacterial activity of the LA producing, Leuconostoc mesenteroides QZ1178 from Qula (fermented food), against G. anatis, using the Oxford cup method. Our data showed that L. mesenteroides QZ1178 inhibited G. anatis isolates from different origins; however, L. mesenteroides QZ1178 antibacterial activity dropped dramatically at pH 5.5–pH 6. The LA concentration and pH of the liquid broth containing L. mesenteroides QZ1178 after 24 h culture was 29 mg/mL and 3.6, respectively. This concentration (29 mg/mL at pH 3.6) and the antibiotic, cefotaxime (minimum inhibitory concentration (MIC) 2.5 μg/mL) effectively inhibited G. anatis (GAC026) growth as observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Gallibacterium anatis treated with LA exhibited extensive cell surface collapse, increased cell damage, cell membrane disruption, and cytoplasmic leakage, indicative of cell lysis. We suggest L. mesenteroides QZ1178 exerts potential antibacterial effects against the poultry pathogen, G. anatis via LA.

Effect of 17β-estradiol on a human vaginal Lactobacillus crispatus strain

Lactobacilli and estrogens play essential roles in vaginal homeostasis. We investigated the potential direct effect of 17β-estradiol on a vaginal strain of Lactobacillus crispatus, the major bacterial species of the vaginal microbiota. 17β-estradiol (10^-6 to 10^-10 M) had no effect on L. crispatus growth, but markedly affected the membrane dynamics of this bacterium. This effect appeared consistent with a signal transduction process. The surface polarity and aggregation potential of the bacterium were unaffected by exposure to 17β-estradiol, but its mean size was significantly reduced. 17β-estradiol also promoted biosurfactant production by L. crispatus and adhesion to vaginal VK2/E6E7 cells, but had little effect on bacterial biofilm formation activity. Bioinformatic analysis of L. crispatus identified a membrane lipid raft-associated stomatin/prohibitin/flotillin/HflK domain containing protein as a potential 17β-estradiol binding site. Overall, our results reveal direct effects of 17β-estradiol on L. crispatus. These effects are of potential importance in the physiology of the vaginal environment, through the promotion of lactobacillus adhesion to the mucosa and protection against pathogens.

Vaginotypes of the human vaginal microbiome

The human vaginal environment harbours a community of bacteria that plays an important role in maintaining vaginal health and in protecting this environment from various urogenital infections. This bacterial population, also known as vaginal microbiota, has been demonstrated to be dominated by members of the Lactobacillus genus. Several studies employing 16S rRNA gene-based amplicon sequencing have classified the vaginal microbiota into five distinct community state types (CSTs) or vaginotypes. To deepen our understanding of the vaginal microbiota we performed an in-depth meta-analysis of 1312 publicly available datasets concerning healthy vaginal microbiome information obtained by metagenomics sequencing. The analysis confirmed the predominance of taxa belonging to the Lactobacillus genus, followed by members of the genera Gardnerella, Vibrio and Atopobium. Moreover, the statistical robustness offered by this meta-analysis allowed us to disentangle the species-level composition of dominant and accessory taxa constituting each vaginotype and to revisit and refine the previously proposed CST classification. In addition, a functional characterization of the metagenomic datasets revealed particular genetic features associated with each assigned vaginotype.

Quantitative modeling predicts mechanistic links between pre-treatment microbiome composition and metronidazole efficacy in bacterial vaginosis

Bacterial vaginosis is a condition associated with adverse reproductive outcomes and characterized by a shift from a Lactobacillus-dominant vaginal microbiota to a polymicrobial microbiota, consistently colonized by strains of Gardnerella vaginalis. Metronidazole is the first-line treatment; however, treatment failure and recurrence rates remain high. To understand complex interactions between Gardnerella vaginalis and Lactobacillus involved in efficacy, here we develop an ordinary differential equation model that predicts bacterial growth as a function of metronidazole uptake, sensitivity, and metabolism. The model shows that a critical factor in efficacy is Lactobacillus sequestration of metronidazole, and efficacy decreases when the relative abundance of Lactobacillus is higher pre-treatment. We validate results in Gardnerella and Lactobacillus co-cultures, and in two clinical cohorts, finding women with recurrence have significantly higher pre-treatment levels of Lactobacillus relative to bacterial vaginosis-associated bacteria. Overall results provide mechanistic insight into how personalized differences in microbial communities influence vaginal antibiotic efficacy.

Understanding the potential of lactobacilli in recurrent UTI prevention

Urinary tract infections (UTIs) are one of the most common infections in women. The only proven preventive strategy for recurrent UTIs is prophylactic antibiotics. Given growing antibiotic resistance, the use of probiotics has been proposed as an alternative to antibiotics. Herein, we discuss the current evidence to support the possibility that exogenous lactobacilli may limit the pathogenicity of uropathogens such as E. coli. Probiotics appear to have a significant potential in prevention of recurrent UTI, however, additional data are needed to understand how they can be effectively used in clinical practice.

Genomic Survey of E. coli From the Bladders of Women With and Without Lower Urinary Tract Symptoms

Urinary tract infections (UTIs) are one of the most common human bacterial infections. While UTIs are commonly associated with colonization by Escherichia coli, members of this species also have been found within the bladder of individuals with no lower urinary tract symptoms (no LUTS), also known as asymptomatic bacteriuria. Prior studies have found that both uropathogenic E. coli (UPEC) strains and E. coli isolates that are not associated with UTIs encode for virulence factors. Thus, the reason(s) why E. coli sometimes causes UTI-like symptoms remain(s) elusive. In this study, the genomes of 66 E. coli isolates from adult female bladders were sequenced. These isolates were collected from four cohorts, including women: (1) without lower urinary tract symptoms, (2) overactive bladder symptoms, (3) urgency urinary incontinence, and (4) a clinical diagnosis of UTI. Comparative genomic analyses were conducted, including core and accessory genome analyses, virulence and motility gene analyses, and antibiotic resistance prediction and testing. We found that the genomic content of these 66 E. coli isolates does not correspond with the participant's symptom status. We thus looked beyond the E. coli genomes to the composition of the entire urobiome and found that the presence of E. coli alone was not sufficient to distinguish between the urobiomes of individuals with UTI and those with no LUTS. Because E. coli presence, abundance, and genomic content appear to be weak predictors of UTI status, we hypothesize that UTI symptoms associated with detection of E. coli are more likely the result of urobiome composition.

[Ten questions about bacterial vaginosis]

The physiopathology of bacterial vaginosis (BV), the ultimate stage of vaginal dysbiosis, has benefited from recent advances in molecular biology, highlighting, among others, the important role of A. vaginae. Certain immunological specificities (variants of TLR4, elevation of IL-1β, for example) explain the variations in the prevalence of this infection, the poor clinical and cellular inflammatory response and the promoting influence of BV on the acquisition and progression of some sexually transmitted infections. These advances do not fully elucidate the causes of the high rate of recurrences. Some risk factors for relapses of BV have been identified such as tobacco use, stress or hygienic errors have been associated to relapses of BV. However, other paths are beginning to be explored such as the role of sexual transmission, the resistance of certain bacteria associated to BV to nitroimidazoles or the lack of efficacy of conventional treatments on dysbiosis itself. Taking into acount this vaginal dysbiosis appears to be important or even essential to better control the natural history of HPV-hr infection or improve the success rate of IVF, for example. Despite heterogeneous results, the use of probiotics as a complement to conventional treatments (nitroimidazoles, dequalinium chloride) has demonstrated a preventive effect on BV recurrences. Further studies are needed to customize the contribution of probiotics (or synbiotics) according to the individual specificities of the vaginal microbiome.

Pathogenesis and in vivo interactions of human Streptococcus agalactiae isolates in the Galleria mellonella invertebrate model

Group B Streptococcus (GBS) is a gram positive bacterium colonizing the gastrointestinal and urogenital tracts in humans. However under certain conditions GBS invades leading to severe infections in neonates, pregnant women, immunocompromised patients and the elderly people. The precise mechanisms involved in the transition from colonizer to pathogen remain to be elucidated, however it has been suggested that environmental determinants may regulate gene expression resulting in GBS invasion. We have assessed the potential of the moth Galleria mellonella as a model to study the in vivo virulence and GBS interactions of invasive and noninvasive human isolates from our population. Temperature, pH and bacterial competition effects were examined in the model as well as the response of Galleria hemocytes to GBS infection. GBS strains were able to effectively grow and infect G. mellonella in a dose dependent manner with a (half-lethal dose) LD₅₀ 1 × 10⁷ CFU after 24 h. GBS infection induced larva melanization with hemocyte vacuolation and depletion. Larval killing increased with environmental conditions such as temperature (37 °C) and pH (≥5.5-7.2). Bacterial interference assays showed a remarkable antagonistic effect of Lactobacillus gasseri (cells and filtrates) on GBS infection and significantly improved Galleria survival. The protective effect of L. gasseri was observed even at ratios similar to those of GBS colonization suggesting that L. gasseri modulation by its metabolic products is relevant. Exposure to L. gasseri acidic filtrates induced growth inhibition and prevented larva killing after infection with the hypervirulent GBS clone (a multiresistant clinical ST 17 strain). We showed that mechanisms mediating these effects are mainly pH dependent, however other mechanisms may have a role depending on inocula. We also found that G. mellonella infected with invasive human GBS isolates showed differential killing curves with higher killing rates after 24 h when compared to those considered colonizers or noninvasive isolates. Overall it has been shown that G. mellonella may be a representative in vivo model for baseline GBS studies. Given the potential effects over the hypervirulent strain, our findings support the use of L. gasseri in the GBS control strategies based on Lactobacillus formulations.

Evaluation of the Inhibitory Effects of Lactobacillus gasseri and Lactobacillus crispatus on the Adhesion of Seven Common Lower Genital Tract Infection-Causing Pathogens to Vaginal Epithelial Cells

Background/Purpose: Lactobacillus colonization is important to maintain urogenital flora stability and prevent pathogenic infection. Different Lactobacillus species have distinct properties and effects on the urogenital flora. To select probiotics that colonize the vagina and provide protection against pathogenic infection, we evaluated the adhesion of five Lactobacillus strains and their inhibitory effects on the adhesion of pathogens to vaginal epithelial cells (VECs). Methods and Materials: (1) Lactobacillus adhesion experiments: VK2/E6E7 and primary VECs were used to evaluate the adhesion of two Lactobacillus gasseri and three Lactobacillus crispatus strains. The adhesion of these five Lactobacillus strains was compared. (2) Adhesion inhibition experiments: The inhibitory effects of the five Lactobacillus strains on the adhesion of pathogens (Gardnerella, Mobiluncus, Candida albicans, Streptococcus agalactiae, Staphylococcus aureus, Escherichia coli, and Enterococcus faecalis) were evaluated by adhesion exclusion, displacement, and competition experiments. Results: (1) Lactobacillus adhesion was stronger in the primary VECs than in the VK2/E6E7 VECs (P < 0.05). The adhesion of the three L. crispatus strains was stronger than that of the two L. gasseri strains (P < 0.05). L. crispatus 4# showed the strongest adhesion. (2) The exclusion, displacement, and competition experiments showed that all five Lactobacillus strains significantly inhibited the adhesion of the seven pathogenic strains to the VECs (P < 0.05). The displacement effect was stronger than the exclusion and competition effects of each Lactobacillus strain. (3) The results of the exclusion, displacement, and competition experiments indicated that L. gasseri 1# showed the strongest adhesion inhibition of C. albicans and S. agalactiae. L. crispatus 3# showed the strongest adhesion inhibition of S. aureus, whereas L. crispatus 4# showed the strongest adhesion inhibition of Gardnerella, Mobiluncus, E. coli, and E. faecalis. Conclusion: The source of the VECs might not affect the selection of the most adhesive Lactobacillus strain. L. crispatus showed stronger VEC adhesion than L. gasseri. The degree of antagonism of the Lactobacillus strains toward the different pathogens varied. This result provides incentives for personalized clinical treatment.