Cervicovaginal Microbiota Research Articles

Protective Mechanisms of Vaginal Lactobacilli against Sexually Transmitted Viral Infections.

The healthy cervicovaginal microbiota is dominated by various Lactobacillus species, which support a condition of eubiosis. Among their many functions, vaginal lactobacilli contribute to the maintenance of an acidic pH, produce antimicrobial compounds, and modulate the host immune response to protect against vaginal bacterial and fungal infections. Increasing evidence suggests that these beneficial bacteria may also confer protection against sexually transmitted infections (STIs) caused by viruses such as human papillomavirus (HPV), human immunodeficiency virus (HIV) and herpes simplex virus (HSV). Viral STIs pose a substantial public health burden globally, causing a range of infectious diseases with potentially severe consequences. Understanding the molecular mechanisms by which lactobacilli exert their protective effects against viral STIs is paramount for the development of novel preventive and therapeutic strategies. This review aims to provide more recent insights into the intricate interactions between lactobacilli and viral STIs, exploring their impact on the vaginal microenvironment, host immune response, viral infectivity and pathogenesis, and highlighting their potential implications for public health interventions and clinical management strategies.

The role of cervicovaginal microbiota in the occurrence of severe cervical intraepithelial dysplasia

BACKGROUND: Despite the availability of visual examination of the cervix, cervical screening in Russia has not been widespread enough, and therefore the incidence of cervical cancer remains consistently high. In recent years, the vaginal microbiota is given special attention as a risk factor for the development of precancerous diseases of the cervix. AIM: The aim of this study was to compare the cervicovaginal microbiota in patients with high-grade squamous intraepithelial lesions (HSIL) or negative for intraepithelial lesions or malignancy (NILM). MATERIALS AND METHODS: Microorganisms isolated from the cervicovaginal microbiota were identified in 40 patients using the mass spectrometry method. 20 women had severe cervical dysplasia, and the other 20 were healthy women without precancerous cervical lesions. RESULTS: Corynebacterium spp. and Streptococcus spp. were found more often in the cervicovaginal microbiome in patients with high-grade squamous intraepithelial lesions than in women negative for intraepithelial lesions or malignancy. CONCLUSIONS: The data obtained suggest that the presence of Corynebacterium spp. and Streptococcus spp. in the cervicovaginal microbiota is associated with the presence of severe cervical intraepithelial changes.

Species-level characterization of the cervicovaginal microbiota and its role in human papillomavirus-associated cervical carcinogenesis.

The cervicovaginal microbiome may contribute to human papillomavirus (HPV)-associated cervical carcinogenesis, but studies have been limited by low-resolution analysis methods. Using a high-resolution bioinformatics pipeline, we evaluated the relationship of the cervicovaginal microbiome with HPV and cervical intraepithelial neoplasia (CIN). The cervicovaginal microbiome of 186 women was characterized by sequencing 16S rRNA regions (V3-V4 and V5-V6) and annotated with the high-resolution ANCHOR pipeline. Samples were genotyped for HPV using the Roche-Cobas 4800 assay. We fitted logistic regression models using stepwise forward selection to select species (presence/absence) as correlates of CIN1+ and constructed a linear microbiome-based score using the regression coefficients. An HPV-based score was calculated from a separate logistic regression model to detect CIN1+ . Receiver operating characteristic curve analyses were performed; the area under the curve (AUC) and 95% confidence intervals (CI) were compared between scores. Overall, 66.7% of participants were HPV-positive. 77 unique species were identified: 8 using V3-V4, 48 using V5-V6, and 21 shared. Twelve species were retained via stepwise selection. The AUCs for the microbiome-, and HPV-based scores were 0.7656 (95% CI 0.6885-0.8426), and 0.7529 (95% CI 0.6855-0.8204), respectively. Bacterial species may be involved in cervical carcinogenesis as the microbiome- and HPV-based scores performed similarly for CIN1+ detection.

Risk factors for the development of cervical cancer: analysis of the evidence

IntroductionCervical cancer (CC) is the fourth most prevalent female cancer globally. Understanding its epidemiology is crucial for devising practical strategies suited to geographic and social contexts to attain the global eradication of CC. Hence, this study examined the latest evidence of risk factors contributing to CC development.MethodsAn independent literature search was conducted on PubMed using MESH terms. The primary sources were meta-analyses published from 2010 to 2023, which detail updated evidence on risk factors associated with CC. Additionally, the quality of the evidence was evaluated using the GRADE system and recommendations were made accordingly.ResultsThe main risk factors related to the cause of CC include co-infections with other sexually transmitted infections, genetic markers, cervicovaginal microbiota, nutritional factors, comorbidities that affect the immune response, smoking, and the use of hormonal contraceptives with a quality evidence based on the GRADE scale moderate.ConclusionsSince the necessary cause for CC is persistent cervicovaginal HPV, all the risk factors implicated in the causality of CC act as non-independent cofactors that increase the risk of CC. Thus, changes in public policies aimed at addressing these risk factors are highly recommended and can substantially decrease the risk of CC.

Leveraging existing 16S rRNA gene surveys to decipher microbial signatures and dysbiosis in cervical carcinogenesis

The presence of dysbiotic cervicovaginal microbiota has been observed to be linked to the persistent development of cervical carcinogenesis mediated by the human papillomavirus (HPV). Nevertheless, the characteristics of the cervical microbiome in individuals diagnosed with cervical cancer (CC) are still not well understood. Comprehensive analysis was conducted by re-analyzing the cervical 16S rRNA sequencing datasets of a total of 507 samples from six previously published studies. We observed significant alpha and beta diversity differences in between CC, cervical intraepithelial neoplasia (CIN) and normal controls (NC), but not between HPV and NC in the combined dataset. Meta-analysis revealed that opportunistic pernicious microbes Streptococcus, Fusobacterium, Pseudomonas and Anaerococcus were enriched in CC, while Lactobacillus was depleted compared to NC. Members of Gardnerella, Sneathia, Pseudomonas, and Fannyhessea have significantly increased relative abundance compared to other bacteria in the CIN group. Five newly identified bacterial genera were found to differentiate CC from NC, with an area under the curve (AUC) of 0.8947. Moreover, co-occurrence network analysis showed that the most commonly encountered Lactobacillus was strongly negatively correlated with Prevotella. Overall, our study identified a set of potential biomarkers for CC from samples across different geographic regions. Our meta-analysis provided significant insights into the characteristics of dysbiotic cervicovaginal microbiota undergoing CC, which may lead to the development of noninvasive CC diagnostic tools and therapeutic interventions.

The Role of Prevotella Species in Female Genital Tract Infections.

Female genital tract infections (FGTIs) include vaginal infections (e.g., bacterial vaginosis [BV]), endometritis, pelvic inflammatory disease [PID], and chorioamnionitis [amniotic fluid infection]. They commonly occur in women of reproductive age and are strongly associated with multiple adverse health outcomes including increased risk of HIV/sexually transmitted infection acquisition and transmission, infertility, and adverse birth outcomes such as preterm birth. These FGTIs are characterized by a disruption of the cervicovaginal microbiota which largely affects host immunity through the loss of protective, lactic acid-producing Lactobacillus spp. and the overgrowth of facultative and strict anaerobic bacteria. Prevotella species (spp.), anaerobic Gram-negative rods, are implicated in the pathogenesis of multiple bacterial FGTIs. Specifically, P. bivia, P. amnii, and P. timonensis have unique virulence factors in this setting, including resistance to antibiotics commonly used in treatment. Additionally, evidence suggests that the presence of Prevotella spp. in untreated BV cases can lead to infections of the upper female genital tract by ascension into the uterus. This narrative review aims to explore the most common Prevotella spp. in FGTIs, highlight their important role in the pathogenesis of FGTIs, and propose future research in this area.

Chemical characterization of Thymus zygis L. (thyme) and Elettaria cardamomum L. (cardamom) essential oils and investigation of their inhibitory potentials against cervicovaginal Escherichia coli isolates

IntroductionThe cervicovaginal microbiota plays a crucial role in women's well-being and reproductive health. This study initially focuses on identifying the chemical components of the essential oils (EOs) from Elettaria cardamomum L. (cardamom) (Ec) and Thymus zygis L. (thyme) (Tz). Subsequently, this study aims to determine the antimicrobial and biofilm inhibitory effects of these EOs against both cervicovaginal mixed cultures and the microbial strains isolated from them. MethodsThe compositions of EOs were determined by GC–MS analysis using an Agilent 7890B GC/5977A Series MSD System. Cervicovaginal samples were obtained from two women presenting complaints of a strong odor and vaginal discharge. Samples were collected from the cervix using a sterile cytobrush, ensuring no contact with the urethra, rectum, or external parts of the vagina. The cytological examination was conducted using Papanicolaou staining. Isolated microorganisms were identified through 16S Ribosomal RNA Gene Sequence Analysis and characterized using antibiogram tests. Antimicrobial tests of the EOs were performed by broth microdilution and disc diffusion methods. Biofilm formation was assessed using a crystal violet binding assay. ResultsThe major components of Ec EO were α-terpinyl acetate (41.95 %) and eucalyptol (28.58 %), whereas Tz EO contained significant amounts of o-cymene (38.76 %), carvacrol (22.66 %), and thymol (20.69 %). Escherichia coli codes OR651248 and OR651249 were isolated from CV 6 and CV 7 mixed cultures, respectively. E. coli OR651248 demonstrated a higher antibiotic resistance level than E. coli OR651249. Biofilm formation by mixed cultures was significantly higher than that by E. coli isolates (P < 0.05). The Ec EO displayed minimal to no effect against both mixed cultures, showing zero inhibition zone, 500 μL/mL minimum inhibitory concentrations (MICs), and 500 μL/mL minimum microbicidal concentrations (MMCs). However, the Tz EO exhibited antimicrobial activity against both mixed cultures and the E. coli isolates, with inhibition zones > 15 mm and MICs/MMCs < 4 μL/mL (P < 0.05). In all microbial cultures, 0.5 MIC of both EOs inhibited biofilm formation by more than 80 %. ConclusionThe Tz EO exhibits promising potential as an antimicrobial and biofilm inhibitory agent for managing cervicovaginal E. coli infections.

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.

HPV-associated cervicovaginal microbiome and host metabolome characteristics

BackgroundCervicovaginal microbiome plays an important role in the persistence of HPV infection and subsequent disease development. However, cervicovaginal microbiota varied cross populations with different habits and regions. Identification of population-specific biomarkers from cervicovaginal microbiota and host metabolome axis may support early detection or surveillance of HPV-induced cervical disease at all sites. Therefore, in the present study, to identify HPV-specific biomarkers, cervicovaginal secretion and serum samples from HPV-infected patients (HPV group, n = 25) and normal controls (normal group, n = 17) in Xichang, China were collected for microbiome (16S rRNA gene sequencing) and metabolome (UHPLC-MS/MS) analysis, respectively.ResultsThe results showed that key altered metabolites of 9,10-DiHOME, α-linolenic acid, ethylparaben, glycocholic acid, pipecolic acid, and 9,12,13-trihydroxy-10(E),15(Z)-octadecadienoic acid, correlating with Sneathia (Sneathia_amnii), Lactobacillus (Lactobacillus_iners), Atopobium, Mycoplasma, and Gardnerella, may be potential biomarkers of HPV infection.ConclusionThe results of current study would help to reveal the association of changes in cervicovaginal microbiota and serum metabolome with HPV infections.

Abstract 750: Specific oral bacterial profile associated with oral HPV status in Puerto Rican People with HIV

Abstract Human papillomavirus (HPV) accounts for more than 70% of oropharyngeal cancers and people with HIV (PWH) are disproportionately affected by HPV infection even with successful antiretroviral therapy. Puerto Rico (PR) is in the top ten in terms of HIV prevalence in the US, and also has disparities in HPV-related malignancies. The oral microbiome can increase the risk of HPV infection and persistence; however, it has not been investigated in the context of HIV in PR. Therefore, we evaluated diversity and composition of the oral bacteriome of 48 virologically suppressed PWH (men and women ≥21 and &amp;lt;64 years old) living in PR in relation to HPV status (HPV+: n=18 vs. HPV-: n=30). We collected saliva (16S rDNA sequencing), oral rinse (HPV genotyping) as well as sociodemographic, lifestyle and behavioral characteristics. Short chain fatty acids (SCFA, acetate, butyrate and propionate) were quantified using gas chromatography and mass spectrometry. Periodontal disease was assessed by a clinical full-mouth periodontal assessment using the CDC/AAP guidelines. All analyses were performed using QIIME2 and R-statistical software. There were no significant differences in alpha diversity (Shannon, observed OTUs, and Faith) between HPV+ and HPV- groups. Absolute CD4 count was not significantly different between HPV+ and HPV- participants (794 cells/µL vs. 735 cells/µL), and did not correlate with either microbial richness or diversity. Higher microbial richness was associated with lower levels of acetate (r=-0.35, p&amp;lt;0.05) and propionate (r=-0.31, p&amp;lt;0.05,). Additionally, higher phylogenetic diversity was also associated with lower levels of acetate (r=-0.38, p&amp;lt;0.05) and propionate (r=-0.35, p&amp;lt;0.05) irrespective of the HPV status. On the other hand, higher levels of butyrate was significantly associated with higher microbial diversity (Shannon index; r=0.33, p&amp;lt; 0.05). Taxonomic analyses showed significantly higher abundance of Dialister and Nanosynbacter genera in HPV+ participants and higher abundance of Rothia genus and Capnocytophaga sputigena in HPV- participants. Overall, we found specific prokaryotic profile and associated metabolites associated with HPV infection, which may suggest that the oral microbiome could influence the natural history of HPV infection via SCFA signaling. Members of the Dialister genus have been found to be prevalent in Hispanic and Black women cervicovaginal microbiota, and as well as in HPV infection and oral cancer. Understanding the underpinning mechanisms of how the oral microbiome can facilitate HPV infection and persistence in PWH is essential to establish targets for early identification and personalized treatment approaches for oral HPV-related malignancies. Citation Format: Yakshi N. Ortiz-Maldonado, Gabriel Borges-Velez, Jurelis Torres-Reyes, Alvin A. Peralta-Betanncourt, Jeannette L. Salgado-Montilla, Jorge Viera-Vera, Maria M. Sanchez-Vazquez, Magaly Martinez-Ferrer, Ana P. Ortiz-Martinez, Ramon F. Gonzalez-Garcia, Josue Perez-Santiago. Specific oral bacterial profile associated with oral HPV status in Puerto Rican People with HIV [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 750.

Ovarian Cancer and the Microbiome: Connecting the Dots for Early Diagnosis and Therapeutic Innovations-A Review.

Ovarian cancer, which ranks eighth among global female cancers and fifth in fatality, poses a significant health challenge owing to its asymptomatic early stages. Understanding the pathogenesis requires extensive research. Recent studies have emphasized the role of the gut and cervicovaginal microbiota in ovarian cancer. This review explores the current understanding of the relationship between the microbiome and ovarian cancer, considering the potential of biomarkers in the serum and various tissues. Insights into the influence of the microbiome on treatments, including surgery and chemotherapy, open doors to innovative approaches, such as fecal microbiome transplantation. This synthesis of recent findings provides crucial insights into the intricate interplay between the microbiome and ovarian cancer, thereby shaping diagnostic and treatment strategies.

Vaginal Microbiota and HPV in Latin America: A Narrative Review.

With the expansion of human microbiome studies in the last 15 years, we have realized the immense implications of microbes in human health. The human holobiont is now accepted, given the commensal relationships with bacteria, fungi, parasites, viruses, and human cells. The cervicovaginal microbiota is a specific case within the human microbiome where diversity is lower to maintain a chemical barrier of protection against infections. This narrative review focuses on the vaginal microbiome. It summarizes key findings on how native bacteria protect women from disease or predispose them to damaging inflammatory processes with an emphasis on the role of HPV infections in Latin America, one of the world's regions with the highest cervical cancer prevalence.

Microbiome markers in HPV-positive and HPV-negative women of reproductive age with ASCUS and SIL determined by V4 region of 16S rRNA gene sequencing.

Human papilloma virus (HPV) is the most common sexually transmitted infection worldwide. Cervicovaginal microbiota plays an important role in HPV infection and is associated with the development of squamous intraepithelial lesions (SIL). The natural history of cervical cancer involves reversible changes in the cervical tissue from a normal state, in which no neoplastic changes are detected in the squamous epithelium, to varying states of cellular abnormalities that ultimately lead to cervical cancer. Low-grade SIL (LSIL), like another cytological category - atypical squamous cells of undetermined significance (ASCUS), may progress to high-grade SIL (HSIL) and invasive cervical cancer or may regress to a normal state. In this work, we studied cervical canal microbiome in 165 HPV-positive and HPV-negative women of a reproductive age with ASCUS [HPV(+) n = 29; HPV(-) n = 11], LSIL [HPV(+) n = 32; HPV(-) n = 25], HSIL [HPV(+) n = 46], and the control group with negative for intraepithelial lesion malignancy (NILM) [HPV(-) n = 22]. HPV16 is the most prevalent HPV type. We have not found any differences between diversity in studied groups, but several genus [like Prevotella (p-value = 0.026), Gardnerella (p-value = 0.003), Fannyhessea (p-value = 0.024)] more often occurred in HSIL group compared by NILM or LSIL regardless of HPV. We have found statistically significant difference in occurrence or proportion of bacterial genus in studied groups. We also identified that increasing of the ratio of Lactobacillus iners or age of patient lead to higher chance to HSIL, while increasing of the ratio of Lactobacillus crispatus lead to higher chance to LSIL. Patients with a moderate dysbiosis equally often had either of three types of vaginal microbial communities (CST, Community State Type) with the prevalence of Lactobacillus crispatus (CST I), Lactobacillus gasseri (CST II), and Lactobacillus iners (CST III); whereas severe dysbiosis is linked with CST IV involving the microorganisms genera associated with bacterial vaginosis and aerobic vaginitis: Gardnerella, Fannyhessea, Dialister, Sneathia, Anaerococcus, Megasphaera, Prevotella, Finegoldia, Peptoniphilus, Porphyromonas, Parvimonas, and Streptococcus.

The Vaginal Microbiota, Human Papillomavirus Infection, and Cervical Carcinogenesis: A Systematic Review in the Latina Population

BackgroundLatina women experience disproportionately higher rates of HPV infection, persistence, and progression to cervical dysplasia and cancer compared to other racial–ethnic groups. This systematic review explores the relationship between the cervicovaginal microbiome and human papillomavirus infection, cervical dysplasia, and cervical cancer in Latinas.MethodsThe review abides by the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. PubMed, EMBASE, and Scopus databases were searched from January 2000 through November 11, 2022. The review included observational studies reporting on the cervicovaginal microbiota in premenopausal Latina women with human papillomavirus infection, cervical dysplasia, and cervical cancer.ResultsTwenty-five articles were eligible for final inclusion (N = 131,183). Forty-two unique bacteria were reported in the cervicovaginal microbiome of Latinas. Seven bacteria: Lactobacillus crispatus, Lactobacillus iners, Chlamydia trachomatis, Prevotella spp., Prevotella amnii, Fusobacterium spp. and Sneathia spp. were enriched across multiple stages of cervical carcinogenesis in Latinas. Therefore, the total number of reported bacteria includes four bacteria associated with the healthy state, 16 bacteria enriched in human papillomavirus outcomes, 24 unique bacteria associated with abnormal cytology/dysplasia, and five bacteria associated with cervical cancer. Furthermore, three studies reported significantly higher alpha and beta diversity in Latinas with cervical dysplasia and cancer compared to controls. Lactobacillus depletion and an increased abundance of L. iners in Latinas compared to non-Latinas, regardless of human papillomavirus status or lesions, were observed.ConclusionsThe identification of 42 unique bacteria and their enrichment in cervical carcinogenesis can guide future cervicovaginal microbiome research to better inform cervical cancer prevention strategies in Latinas.

Cervicovaginal microbiota long-term dynamics and prediction of different outcomes in persistent human papillomavirus infection.

Persistent human papillomavirus (HPV) infection can lead to cervical intraepithelial neoplasia (CIN) and cervical cancer, posing serious threats to the health of women. Although the cervicovaginal microbiota is strongly associated with CIN, the dynamics of the microbiota during CIN development are unknown. In this retrospective cohort study, we analyzed 3-year longitudinal data from 72 patients diagnosed with a persistent HPV infection almost all caused by high-risk HPV types. Patients were categorized into groups with HPV persistent infection (n = 37), progression to CIN (n = 16), and CIN regression (n = 19) based on infection outcome during the follow-up period. Furthermore, 16S rRNA gene sequencing was performed on consecutively collected cervical samples to explore the composition and dynamics of the cervicovaginal microbiota during the development and regression of CIN. Our results showed that the composition of the cervicovaginal microbiota varied among women with different HPV infection outcomes and remained relatively stable during the follow-up period. Notably, the serial follow-up data showed that these microbial alterations were present for at least 1-2 years and occurred before pathologic changes. In addition, microbial markers that were highly discriminatory for CIN progression or regression were identified. This study provides evidence for a temporal relationship between changes in the cervicovaginal microbiota and the development of CIN, and our findings provide support for future microbial intervention strategies for CIN.

The role of neighborhood deprivation in the cervicovaginal microbiota

BackgroundLactobacillus-deficient cervicovaginal microbiota is associated with spontaneous preterm birth and is more common among Black individuals. Persistent racial segregation in the United States has led to differential neighborhood exposures by race that can affect pregnancy outcomes. The extent to which neighborhood exposures may explain racial differences in the cervicovaginal microbiota is unknown. ObjectiveWe sought to determine if neighborhood deprivation, defined as material community deprivation, is associated with a Lactobacillus-deficient cervicovaginal microbiota in a prospective cohort of pregnant individuals. Our hypothesis is that racial differences in neighborhood deprivation may explain the higher prevalence of Lactobacillus-deficient cervicovaginal microbiota in Black birthing people. Design/MethodsWe analyzed data from Motherhood & Microbiome, a prospective pregnancy cohort enrolled from prenatal clinics in a single hospital system 2013-2016 in which a Lactobacillus-deficient cervicovaginal microbiota was previously shown to be associated with spontaneous preterm birth. We geocoded addresses to obtain census tract neighborhood deprivation data from the Brokamp Nationwide Community Deprivation Index that uses weighted proportions of poverty, income, public assistance, lack of health insurance, and vacant housing. Generalized linear mixed models quantified associations of deprivation with the cervicovaginal microbiota accounting for geographical clustering by census tract and potential confounders. Due to different distributions of neighborhood deprivation and the cervicovaginal microbiota, we performed race-stratified models. Mediation analyses quantified the extent to which deprivation may contribute to racial differences in the cervicovaginal microbiota. ResultsHigher neighborhood deprivation was associated with a Lactobacillus-deficient cervicovaginal microbiota. Per standard deviation increment of deprivation, participants had 28% higher adjusted odds (aOR 1.28, 95% CI: 1.04-1.58) of a Lactobacillus-deficient microbiota. Black participants had higher odds of a Lactobacillus-deficient microbiota than White participants (aOR 4.00, 95% CI: 2.05, 8.26), and mediation analysis revealed that deprivation accounted for 22% (P=0.046) of that disparity. ConclusionNeighborhood deprivation was associated a Lactobacillus-deficient cervicovaginal microbiota and may partially explain Black-White disparities in the cervicovaginal microbiota. Mechanistic studies to explore how environmental exposures modify the cervicovaginal microbiota are warranted to identify novel opportunities for future interventional strategies to prevent preterm birth. As these findings demonstrate a potential biologic impact from neighborhood conditions, policies that drive urban planning should be explored to improve pregnancy outcomes.

Human Papillomavirus Infections and the Role Played by Cervical and Cervico-Vaginal Microbiota-Evidence from Next-Generation Sequencing Studies.

This comprehensive review encompasses studies examining changes in the cervical and cervico-vaginal microbiota (CM and CVM) in relation to human papillomavirus (HPV) using next-generation sequencing (NGS) technology. HPV infection remains a prominent global health concern, with a spectrum of manifestations, from benign lesions to life-threatening cervical cancers. The CM and CVM, a unique collection of microorganisms inhabiting the cervix/vagina, has emerged as a critical player in cervical health. Recent research has indicated that disruptions in the CM and CVM, characterized by a decrease in Lactobacillus and the overgrowth of other bacteria, might increase the risk of HPV persistence and the progression of cervical abnormalities. This alteration in the CM or CVM has been linked to a higher likelihood of HPV infection and cervical dysplasia. NGS technology has revolutionized the study of the cervical microbiome, providing insights into microbial diversity, dynamics, and taxonomic classifications. Bacterial 16S rRNA gene sequencing, has proven invaluable in characterizing the cervical microbiome, shedding light on its role in HPV infections and paving the way for more tailored strategies to combat cervical diseases. NGS-based studies offer personalized insights into an individual's cervical microbiome. This knowledge holds promise for the development of novel diagnostic tools, targeted therapies, and preventive interventions for cervix-related conditions, including cervical cancer.

Microbiota dynamics, metabolic and immune interactions in the cervicovaginal environment and their role in spontaneous preterm birth.

Differences in the cervicovaginal microbiota are associated with spontaneous preterm birth (sPTB), a significant cause of infant morbidity and mortality. Although establishing a direct causal link between cervicovaginal microbiota and sPTB remains challenging, recent advancements in sequencing technologies have facilitated the identification of microbial markers potentially linked to sPTB. Despite variations in findings, a recurring observation suggests that sPTB is associated with a more diverse and less stable vaginal microbiota across pregnancy trimesters. It is hypothesized that sPTB risk is likely to be modified via an intricate host-microbe interactions rather than due to the presence of a single microbial taxon or broad community state. Nonetheless, lactobacilli dominance is generally associated with term outcomes and contributes to a healthy vaginal environment through the production of lactic acid/maintenance of a low pH that excludes other pathogenic microorganisms. Additionally, the innate immunity of the host and metabolic interactions between cervicovaginal microbiota, such as the production of bacteriocins and the use of proteolytic enzymes, exerts a profound influence on microbial populations, activities, and host immune responses. These interplays collectively impact pregnancy outcomes. This review aims to summarize the complexity of cervicovaginal environment and microbiota dynamics, and associations with bacterial vaginosis and sPTB. There is also consideration on how probiotics may mitigate the risk of sPTB and bacterial vaginosis.

A Decrease in Lactobacilli in the Vaginal Microbiota Is Independently Associated With HPV Persistence in Women With High-Risk HPV Infection.

Background Vaginal dysbiosis, an imbalance between species, can initiate some local changes in immune and metabolic signaling causing chronic inflammation. The mechanism of the clearance or progression of the HPV infection has not been uncovered yet. We hypothesized thatvaginal dysbiosis may contribute tothe persistence of the cervical HPV infection. Therefore weaimed to determine the association of lactobacillus dominancy index with cervical HR-HPV persistence. Methods A total of 100 women who were followed up because of high-risk HPV infection were defined as the target study group. The patients were evaluated in two groups; HPV positive (group with HPV persistence, n=43) and HPV negative (group with HPV clearance, n=57). Cervicovaginal swab samples and blood samples were evaluated for Nugent score, lactobacillus dominance, and white blood cell count.Statistical tests were performed by the IBM Statistical Product and Service Solutions (version 22, IBM SPSS Statistics for Windows, Armonk, NY) program. The continuous variables were presented using the mean±standard deviation (SD), and the categorical variables were presented as the number of cases and their percentage. A p value less than 0.05 (<0.05) was set as statistically significant. Results HPV persistence was observed in 43 (43%) patients. Univariate analysis revealed that age, menopausal status, and lactobacillus reduction were associated with HPV persistence (p<0.05).The median value of the Nugent score was similar among groups.After logistic regression analysis, lactobacillus reduction continued to be associated with HPV persistence, independent of age and menopause (OR:2.668, 96% CI:1.069-6.662, p<0.05) Conclusions A decrease in lactobacilli in the cervicovaginal microbiota is associated with the persistence of HPV, regardless of age and menopausal status in this study.

Inflammatory cytokines and a diverse cervicovaginal microbiota associate with cervical dysplasia in a cohort of Hispanics living in Puerto Rico.

Cervical cancer (CC) is women's fourth most common cancer worldwide. A worrying increase in CC rates in Hispanics suggests that besides Human papillomavirus infections, there may be other cofactors included in the epithelial microenvironment that could play a role in promoting the disease. We hypothesized that the cervical microbiome and the epithelial microenvironment favoring inflammation is conducive to disease progression in a group of Hispanics attending gynecology clinics in Puerto Rico. Few studies have focused on the joint microbiota and cytokine profile response in Hispanics outside the US, especially regarding the development of precancerous lesions. We aimed to investigate the relationship between the cervicovaginal microbiome and inflammation in Hispanic women living in PR while considering cervical dysplasia and HPV genotype risk. Cervical samples collected from 91 participants coming to gynecology clinics in San Juan, underwent 16S rRNA genes (V4 region) profiling, and cytokines were measured using Luminex MAGPIX technology. Cytokines were grouped as inflammatory (IL-1β, TNFα, IFNγ, IL-6), anti-inflammatory (IL- 4, IL-10, TGFβ1), and traffic-associated (IL-8, MIP1a, MCP1, IP10). They were related to microbes via an inflammation scoring index based on the quartile and tercile distribution of the cytokine's concentration. We found significant differences in the diversity and composition of the microbiota according to HPV type according to carcinogenic risk, cervical disease, and cytokine abundance. Community State Types (CSTs) represents a profile of microbial communities observed within the vaginal microbiome ecological niche, and Lactobacillus-depleted CST IV had ~ 90% dominance in participants with high-grade squamous intraepithelial lesions and high-risk HPV. The increasing concentration of pro-inflammatory cytokines was associated with a decrease in L. crispatus. In contrast, dysbiosis-associated bacteria such as Gardnerella, Prevotella, Atopobium concomitantly increased with pro-inflammatory cytokines. Our study highlights that the cervical microbiota of Hispanics living in Puerto Rico is composed mostly of diverse CST profiles with decreased Lactobacillus and is associated with a higher pro-inflammatory environment. The joint host-microbe interaction analyses via cytokine and microbiota profiling have very good translational potential.