Search Results (217)

Bacterial vaginosis (BV) and aerobic vaginitis (AV) are usually described as distinct forms of vaginal dysbiosis. BV is characterized by depletion of lactobacilli, overgrowth of anaerobic microorganisms, and biofilm formation, whereas AV is associated with inflammatory changes, epithelial disruption, and predominance of aerobic bacteria. Over the past two decades, this distinction has profoundly influenced the understanding, diagnosis, and management of vaginal disorders. Despite their apparent differences, the relationship between BV and AV remains incompletely understood. Growing evidence indicates that many women exhibit microbiological and microscopic patterns that cannot be readily classified within existing diagnostic frameworks. Intermediate Nugent scores, mixed vaginitis, transitional ecological states, post-treatment microbiota reconstitution, physiological hypoestrogenic conditions, and uncommon inflammatory patterns all challenge the traditional view of BV and AV as strictly separate entities. This narrative review examines the historical evolution of BV and AV concepts, compares their microbiological, immunological, and epithelial characteristics, and evaluates the diagnostic paradigms currently used to identify vaginal dysbiosis. The strengths and limitations of clinical and diagnostic approaches are discussed together with the extent to which contemporary international guidelines reflect current biological knowledge. Particular emphasis is placed on intermediate, mixed, and overlapping states that blur the boundaries between established diagnostic categories. The available evidence supports the clinical usefulness of distinguishing BV and AV as separate clinicopathological entities. However, it also indicates that vaginal ecosystem disturbances frequently extend beyond rigid dichotomous classifications. Current diagnostic categories remain valuable tools for clinical practice, yet they may only partially capture the complexity and dynamic nature of vaginal dysbiosis. Understanding how microbial communities, host responses, epithelial integrity, and physiological factors interact remains a major challenge for future research and clinical interpretation. Full article

The cervicovaginal microflora plays a vital role in maintaining vaginal health, and disturbances can predispose women to opportunistic infections and sexually transmitted infections (STIs). This study examined the prevalence and associated factors of Candida species, bacterial vaginosis (BV), and their co-occurrence among women in the Eastern Cape province of South Africa. A cross-sectional design was employed, enrolling 325 women aged 18–60 years from a health facility in the Eastern Cape, South Africa. Candida species were identified in cervical specimens using a Seegene Allplex™ Candidiasis Assay. BV status and BV-associated bacteria were identified via Seegene Allplex™ Bacterial Vaginosis Plus assays. Overall, 64.51% of participants were HIV-positive, 15.74% tested positive for Candida species, 52.85% tested positive for BV, and 7.10% were positive for BV–Candida species co-occurrence. The highest prevalence of Candida species (23.60%; R² = 0.913; p = 0.015), BV (85.39%; R² = 0.931; p = 0.003), and Candida–BV co-occurrence (7.10%; R² = 0.903, p = 0.041) was observed in the 18–29 age group and declined significantly with age. Women with four to six lifetime sexual partners had higher odds of testing positive for Candida species (AOR: 2.42, 95% CI: 1.21–4.82, p = 0.012). Currently presenting with STI symptoms (AOR: 4.66; 95% CI: 1.29–16.87; p = 0.019), increased (four to six) lifetime sexual partners (AOR: 5.58; 95% CI: 1.16–26.82; p = 0.032), and being HPV-positive (AOR: 7.28; 95% CI: 1.17–45.26; p = 0.033) were independent predictors of Candida–BV co-occurrences. In this current study, having multiple lifetime sexual partners was independently associated with Candida species positivity, while current STI symptoms, HPV infection, and having four to six lifetime sexual partners significantly increased the likelihood of Candida–BV co-occurrence, highlighting the role of sexual behaviour in the vaginal microbial profile. This underscores the need for continued surveillance and longitudinal investigation. Longitudinal studies to further investigate these associations are warranted. Full article

Gynecological malignancies and breast cancer impose substantial health and economic burdens. This review examines how local and systemic microbiota may affect epithelial integrity, inflammation, estrogen metabolism, and immunity. The vaginal ecosystem is the most extensively studied female microbial niche. Cervical cancer serves as the most illustrative clinical example: loss of stable Lactobacillus crispatus dominance and increased prevalence of anaerobic bacteria (anaerobic dysbiosis) are associated with persistent HPV infection, which directly elevates the risk of cervical precancerous lesions. The estrobolome is particularly relevant in endometrial cancer, where intestinal bacterial beta-glucuronidase activity may increase estrogen reabsorption, particularly in obesity and metabolic disease. In ovarian cancer, microbiota is being studied as a possible risk modifier in BRCA1 carriers, but the evidence remains exploratory. In breast cancer, intratumoral bacteria may shape the immune microenvironment, particularly in triple-negative disease. The primary limitation of current research is methodological heterogeneity. Low-biomass samples, such as those from the ovary or endometrium, are highly susceptible to technical contamination. Most studies are cross-sectional and cannot establish causality. Current evidence supports microbiota as a modifier, not a standalone marker or a substitute for standard diagnosis and treatment. Its most plausible near-term role is in multiparameter risk or response models, pending standardized prospective validation. Full article

Persistent high-risk human papillomavirus (HPV) infection drives cervical cancer, a leading cause of cancer-related mortality among women in low- and middle-income countries; its clinical course is shaped by the cervicovaginal microbiome, in which Lactobacillus-dominated communities are associated with enhanced viral clearance. Despite this, vaginal probiotic interventions often demonstrate limited colonization efficiency, and autochthonous strain libraries from Central Asia remain absent. We applied a tiered functional screening workflow to a collection of 235 vaginal lactic acid bacterial isolates recovered from 400 women undergoing routine gynecological examination in Astana, Kazakhstan. The workflow sequentially filtered isolates on (i) antimicrobial activity against seven urogenital indicator pathogens using the deferred antagonism assay, (ii) surface adhesion by the Brilis erythrocyte assay, and (iii) biofilm-forming capacity by crystal violet retention and laser-capture-microdissection (LCM) microscopy. Species-level identification of the selected candidate was performed by whole-genome shotgun sequencing followed by Kraken2 taxonomic classification. From 235 isolates, three rounds of phenotypic filtering identified four broad-spectrum antimicrobial candidates (127-3, 127-4, 107-2, 107-4) with non-overlapping inhibitory profiles against seven urogenital indicator strains. Adhesion phenotyping segregated candidates into low- and moderate-adhesion groups, with none reaching the high-adhesion threshold. Among all four candidates, only strain 127-4 produced a reproducible biofilm-associated signal (crystal violet retention OD490 = 0.09 ± 0.07 at 24 h; 0.08 ± 0.03 at 48 h), consistent with early surface attachment under static conditions. Whole-genome shotgun sequencing assigned 97.81% of classified reads to Lactiplantibacillus plantarum, supporting preliminary identification of the selected isolate as L. plantarum strain 127-4. Composite ranking confirmed 127-4 as the only isolate combining broad antimicrobial activity (5/7 indicators), moderate adhesion (specific adhesion index, SPA = 2.95), and a detectable biofilm-associated phenotype. We report the first systematic functional screening of autochthonous cervicovaginal lactic acid bacteria from a Central Asian population and identify L. plantarum 127-4 as a probiotic candidate with an integrated trait profile rarely identified through single-criterion screening approaches. Beyond candidate identification, this work establishes a transferable workflow for assembling functionally annotated vaginal Lactobacillus collections from underrepresented populations, providing a foundation for future population-specific probiotic interventions targeting cervicovaginal health. Full article

Background/Objectives: Prophylactic antimicrobial use prior to mating in clinically healthy breeding bitches based on vaginal culture results is common despite lacking evidence for a beneficial effect on fertility. Thus, this practice is questionable due to the risk of the development of antimicrobial resistance and dysbiosis. The study aimed to investigate whether vaginal bacteria and antimicrobial treatment influence the pregnancy outcome. Methods: We retrospectively analyzed vaginal swab results from healthy breeding bitches prior to mating. Samples were examined using aerobic culture, and bacterial isolates were identified by MALDI-TOF. The medical records provided data on antimicrobial treatment and pregnancy outcome. Results: Of the 961 available samples, 467 cases had complete information about antimicrobial use and pregnancy outcome. Overall pregnancy rates did not differ significantly between antimicrobial-treated (81.7%) and untreated bitches (79.8%) (p = 0.6922), nor in cases with monocultures (p = 0.4823), high-grade bacterial growth (p = 0.4291), or high-grade growth of Escherichia coli (p > 0.9999) and Streptococcus canis (p = 0.711). Conclusions: In this study population, antimicrobial use did not improve pregnancy rates in healthy bitches, even in cases of opportunistic bacteria. No correlation between vaginal bacteria, antimicrobial use, and pregnancy outcome was identified. Based on these findings, antimicrobial treatment of clinically healthy animals as part of breeding management cannot be recommended and should be disregarded in the context of responsible antimicrobial use. Full article

Bacteriophages are increasingly investigated as tools for studying and manipulating microbial communities in cattle. However, phage isolation remains challenging because of host specificity, microbial ecosystem differences, and the lack of optimized screening approaches. The objectives of this study were to (i) optimize the phage-screening method for microbial samples obtained from different cattle body sites, (ii) isolate lytic phages against key bovine pathogens and commensal bacteria, and (iii) characterize the isolated phages and their bacterial hosts. A total of 1214 samples from different cattle body sites (n = 1194) and environmental sources (n = 20) were screened using 13 phage detection methods, including one high-throughput approach. Eighty-three phages were isolated, primarily from ruminal fluid (59), feces (15), vaginal (7) and nasopharyngeal swabs (1), and fetal ruminal fluid (1). The bacterial hosts inhibited by these phages were from 29 genera, with Bacillus (34), Escherichia/Shigella (8), Shouchella (5), Corynebacterium (4), and Lysinibacillus (4) being the most common. No phages were identified against bovine pathogens including Trueperella pyogenes, Mannheimia haemolytica, Pasteurella multocida, or Moraxella bovis. Method 12 demonstrated the highest efficiency in phage recovery, particularly from ruminal samples. The successful recovery of bacteriophages from gastrointestinal, reproductive, respiratory, and fetal bovine samples demonstrates the utility of the optimized screening methods for isolating phages from diverse cattle-associated microbial ecosystems. Further studies are needed to refine these approaches to improve the recovery of phages targeting bovine pathogens. Full article

Uterine infections (metritis and endometritis) are a leading cause of culling and reproductive failure in transition dairy cows, and antibiotic-resistant Gram-negative pathogens limit conventional therapy. This randomized, controlled, multi-farm field trial evaluated whether four intravaginal infusions of a host-adapted lactic acid bacteria (LAB) cocktail (Lactobacillus sakei FUA3089, Pediococcus acidilactici FUA3138, P. acidilactici FUA3140; 10⁸–10⁹ cfu/dose) at −3, −2, +3, and +4 weeks relative to calving reduce periparturient disease and improve milk production. A total of 526 pregnant cows (426 Holstein, 100 Jersey) from four commercial Alberta farms (automatic-milking, parlor, and certified-organic systems) were block-randomized within farm and parity to TRT1 (saline; n = 175), TRT2 (saline + skim milk; n = 176), or TRT3 (LAB cocktail in saline + skim milk; n = 175). Uterine infection incidence was assessed by Metricheck™ mucus scoring and transrectal ultrasonography at +3 and +4 weeks postpartum. Across the principal peripartum infectious outcomes, TRT3 showed a consistent protective effect: uterine infection incidence was lowest in TRT3 (18.8% vs. 25.1% in pooled controls; OR = 0.69; 95% CI, 0.44–1.09; an approximately 25% relative reduction; exact p = 0.12), and this metritis signal was additionally supported by a repeated-measures mixed model accounting for farm, parity, and week (p = 0.0175), although the Bonferroni-adjusted pairwise contrasts were tendencies (adjusted p ≈ 0.12), and the effect did not differ by parity (treatment × lactation interaction, p = 0.97). Subclinical mastitis was numerically lower in TRT3 than in pooled controls (5.3% vs. 8.9%; OR = 0.57; 95% CI, 0.27–1.24; exact p = 0.16), whereas retained placenta, milk fever, displaced abomasum, and lameness showed no clear cow-level treatment effect in the cow-level exact analyses. Milk yield increased significantly in multiparous cows, which produced 4.6 L/day more milk than TRT1 and 3.22 L/day more than TRT2 over the first 50 days in milk (p < 0.01 for both contrasts; treatment × parity interaction, p = 0.01). No effect was seen on milk composition, uterine involution, or reproductive performance. The trial supports intravaginal LAB as a candidate antibiotic-free prophylactic whose response depends on farm- and cow-level contexts and whose mechanisms require confirmation through microbiological and metabolic measurements. Full article

Dairy cows are frequently affected by postpartum uterine infections, such as metritis and endometritis, which negatively impact fertility and cause significant economic losses. The extensive use of antibiotics may alter the reproductive microbiota and contribute to the emergence of antibiotic resistance. This study aimed to isolate lactic acid bacteria (LAB) from healthy vaginal samples of cows and evaluate their antimicrobial activity against uterine pathogens such as Escherichia coli and Salmonella spp. Phenotypic characterization and antibiotic susceptibility testing were performed, along with antagonistic assays using both overlay and well diffusion methods. The results demonstrated strain-dependent inhibitory activity against E. coli, with inhibition zones ranging from 2 to 4 mm depending on the LAB strain and the method used, whereas no inhibitory activity was observed against Salmonella. These findings support the potential application of selected LAB strains in bovine reproductive health management. However, further in vitro and in vivo studies are required to confirm their efficacy, safety, and stability under physiological conditions. Full article

This study developed two Causal Graphical Models (CGMs) to analyze the transitions associated with Bacterial Vaginosis (BV) and to identify key bacterial species at each stage. BV results from an imbalance in the vaginal microbiota, whose composition varies among women and across developmental stages. A previous CGM identified influential bacteria but did not address changes between microbiota states. Here, we extend that framework to capture these associations. Path Analysis, a structural equation modeling method based on observed variables that estimates effects through correlations and covariances, was applied to a dataset of 132 pregnant women (4–24 weeks of gestation) from Tabasco, Mexico, previously collected by third parties during healthy pregnancy campaigns and associated with BV diagnosis. Models were validated using statistical metrics and evaluation by a clinical microbiologist. The first model, representing the transition from normal microbiota (BV−) to an indeterminate state (I), identified Megasphaera Type 1 as significant. The second model, from I to bacterial vaginosis-positive (BV+), identified Atopobium vaginae and Bacterial Vaginosis-Associated Bacterium Type 2 as significant contributors. These findings highlight the importance of the intermediate state in dysbiosis progression and support the use of CGMs for studying microbiome dynamics. Full article

Mucin is the core component of the mucus layer barrier in the human reproductive tract and the interaction between mucin and commensal bacteria is crucial for the female reproductive health. In this study, we found that the female reproductive tract isolate Lactobacillus gasseri YS1021 could degrade and utilize mucin to obtain the promoted proliferation. After 48 h of cultivation with 1% mucin added, the biomass of strain YS1021 increased fourfold compared to the control group without mucin. Meanwhile, the addition of mucin induced a 5-fold higher expression of the M13 family metalloprotease encoding gene RS7445, revealing that the enzyme was associated with mucin degradation in the strain YS1201. Moreover, the recombinant strain L. gasseri 7445OE with RS7445 over-expression exhibited an enhanced mucin degradation ability and reached a 7-fold higher biomass than the parent strain YS1021 after 48 h of cultivation with addition of 1% mucin. Furthermore, the gene RS7445 was expressed in Escherichia coli BL21, and the 74 kDa recombinant protein of RS7445 was successfully purified. Enzymatic hydrolysis assay in vitro showed that mucin was decomposed into 39 peptide fragments by the recombinant RS7445, which demonstrated that the M13 family metalloprotease contributes to mucin degradation in L. gasseri YS1021. In sum, this study revealed an important mechanism by which the vaginal L. gasseri YS1021 could degrade and utilize mucin to gain a growth advantage. Full article

The equine reproductive microbiota has emerged as an important factor influencing reproductive health and fertility in both mares and stallions. Traditionally, the equine uterus was considered sterile, and microbial presence was interpreted primarily in the context of infection. However, sequencing-based studies have demonstrated that the reproductive tract, including the uterus and semen, contains detectable microbial communities or microbial DNA signatures, challenging this traditional paradigm. In mares, the vaginal microbiota is consistently dominated by Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, whereas the uterine environment represents a low-biomass niche in which interpretation is complicated by contamination risk and the inability of sequencing-based methods to distinguish viable from nonviable microorganisms. Culture-based studies consistently identify opportunistic pathogens such as Streptococcus equi subsp. zooepidemicus, Escherichia coli, and Pseudomonas aeruginosa in association with endometritis and persistent breeding-induced endometritis, while sequencing-based studies suggest broader community-level dysbiosis rather than simple pathogen presence. In stallions, semen is not sterile and commonly contains taxa such as Porphyromonas, Corynebacterium, Peptoniphilus, and other opportunistic bacteria that may influence sperm quality and microbial transmission to mares during breeding. However, most reported associations remain correlative, and direct longitudinal evidence for persistent stallion-to-mare microbial transmission is limited. This review synthesizes current evidence on microbial composition, hormonal influences, dysbiosis, and reproductive implications of the equine reproductive microbiota, integrating culture-based and sequencing-based findings while emphasizing methodological limitations associated with low-biomass samples. Improved understanding of these microbial ecosystems may support more evidence-based reproductive diagnostics and microbiome-informed fertility management in horses. Full article

Milk production in dairy herds is determined by both intrinsic and extrinsic factors, with reproductive efficiency serving as a primary determinant. Infectious, nutritional, and management-related challenges can reduce this efficiency. Following parturition, cows are more susceptible to clinical disorders due to a temporary loss of integrity in the cervix, vagina, and vulva, which allows environmental bacteria to ascend and alter the vaginal microbiota. These microbial changes may disrupt endocrine responses related to conception and contribute to repeat breeder cow syndrome (RBCS), which is defined as failure to conceive after three or more inseminations. This study investigated associations among cultivable vaginal bacteria, circulating progesterone and glucose concentrations, and reproductive performance in 30 fourth-parity Holstein cows with a body condition score of 3.5. Cows were classified by reproductive history as repeat breeders (RBCS; n = 14) or controls (CTL; n = 16). Vaginal mucosal samples were collected at insemination and cultured on blood agar and MacConkey media under aerobic and microaerobic conditions. Bacterial identification was conducted using Gram staining and standard biochemical assays. Blood samples were collected at insemination, on day 5 post-insemination, and every two days thereafter to measure progesterone and glucose concentrations. Fertility outcomes were analyzed using PROC GLIMMIX, and hormonal data were analyzed using mixed models with repeated measures. The bacterial genera identified included Bacillus, Escherichia coli, Staphylococcus, Klebsiella, Proteus, Streptococcus, and Actinomyces. Progesterone and glucose concentrations did not differ significantly between groups (p > 0.05). However, the fertility rate (p < 0.05; CTL:87.50% vs. RBCS:57.14%) and number of attempts to conceive (p < 0.001; CTL:2.5 vs. RBCS:6.7) differed statistically between treatments. A higher prevalence of S. hyicus was detected in RBCS cows, and E. coli, S. hyicus, and Proteus spp. were more frequently detected in non-pregnant cows. These findings suggest that the identified cultivable vaginal bacteria are associated with reproductive status in dairy cows. Full article

Bacterial vaginosis (BV) is a common vaginal dysbiosis characterized by the depletion of Lactobacillus species and the overgrowth of facultative anaerobic bacteria, particularly Gardnerella spp. and Fannyhessea vaginae. The vaginal microbiota plays a key role in local immune modulation, and BV has been associated with a molecular pro-inflammatory profile. This study included 152 women with normal microbiota (n = 68), intermediate microbiota (n = 24), or BV (n = 60). Vaginal lavage samples were used to quantify Gardnerella spp. and F. vaginae and to measure IL-1β, IL-6, CXCL-8, IL-10, and TNF-α levels. Bacterial loads of Gardnerella spp. were significantly higher in the BV group than in normal microbiota (p < 0.001). F. vaginae loads were higher in BV than in both normal and intermediate microbiota (p < 0.001). IL-1β levels were increased in intermediate microbiota (p = 0.011) and BV (p = 0.024) compared with normal microbiota, while CXCL-8 levels were higher in intermediate microbiota (p = 0.021). No differences were observed for IL-6, IL-10, or TNF-α. BV is associated with increased Gardnerella spp. and F. vaginae loads and a selective increase in IL-1β, supporting a distinct inflammatory signature linked to vaginal dysbiosis. Full article

Reproductive performance is a key determinant of overall livestock productivity. In both beef and dairy systems, reproductive failure represents a leading cause of cow culling. Reproductive traits are complex in nature and present a low heritability in general. Additionally, the collection of such phenotypes usually relies on indirect measures of fertility, such as conception success. Therefore, further investigation into genetic and non-genetic factors of reproductive traits in cattle is necessary. The hosts’ microbiome plays a crucial role in vertebrate biology, including reproduction. We, therefore, hypothesize that microbiome indicators may serve as a biomarker of fertility. This study explored the relationship between vaginal microbiome profiles and pregnancy among three beef cattle genetic groups using field data. Vaginal swabs were collected from 74 cows at Fort Keogh, MT, including 23 Angus, 23 Hereford Line 1, and 28 crossbreds, and DNA was extracted and analyzed via 16S rRNA gene amplification. Significant differences in alpha diversity (p < 0.05) were found among Line 1 cows compared to Angus and crossbreds in many indicators of alpha diversity. Pregnancy status did not influence alpha diversity of samples significantly, but trends toward significance were observed. PERMANOVA analysis indicated that genetic groups and pregnancy status affected microbial composition (p < 0.05), but their interaction was not significant. Each genetic group showed unique compositions of operational taxonomic units (OTUs), with higher proportions of Ureaplasma and Mycoplasma families in Line 1. Additionally, variations in microbial communities were observed between pregnant and non-pregnant cows, with certain uncultured bacteria more prevalent in non-pregnant cows. While field data are useful for such studies and represent a real production system, better-designed experiments are necessary to validate findings and test hypotheses. These results suggest variation in vaginal microbiomes across breeds and pregnancy status, emphasizing the need for further research to identify factors affecting these changes. Full article