Therapeutic activity of a Saccharomyces cerevisiae-based probiotic and inactivated whole yeast on vaginal candidiasis

Fungal burden, dimorphic transition and candidalysin: Role in Candida albicans-induced vaginal cell damage and mitochondrial activation in vitro

Candida albicans (C. albicans) can behave as a commensal yeast colonizing the vaginal mucosa, and in this condition is tolerated by the epithelium. When the epithelial tolerance breaks down, due to C. albicans overgrowth and hyphae formation, the generated inflammatory response and cell damage lead to vulvovaginal candidiasis (VVC) symptoms. Here, we focused on the induction of mitochondrial reactive oxygen species (mtROS) in vaginal epithelial cells after C. albicans infection and the involvement of fungal burden, morphogenesis and candidalysin (CL) production in such induction. Bioluminescent (BLI) C. albicans, C. albicans PCA-2 and C. albicans 529L strains were employed in an in vitro infection model including reconstituted vaginal epithelium cells (RVE), produced starting from A-431 cell line. The production of mtROS was kinetically measured by using MitoSOX™ Red probe. The potency of C. albicans to induced cell damage to RVE and C. albicans proliferation have also been evaluated. C. albicans induces a rapid mtROS release from vaginal epithelial cells, in parallel with an increase of the fungal load and hyphal formation. Under the same experimental conditions, the 529L C. albicans strain, known to be defective in CL production, induced a minor mtROS release showing the key role of CL in causing epithelial mithocondrial activation. C. albicans PCA-2, unable to form hyphae, induced comparable but slower mtROS production as compared to BLI C. albicans yeasts. By reducing mtROS through a ROS scavenger, an increased fungal burden was observed during RVE infection but not in fungal cultures grown on abiotic surface. Collectively, we conclude that CL, more than fungal load and hyphae formation, seems to play a key role in the rapid activation of mtROS by epithelial cells and in the induction of cell-damage and that mtROS are key elements in the vaginal epithelial cells response to C. albicans.

Multifactorial inhibition of Candida albicans by combinations of lactobacilli and probiotic Saccharomyces cerevisiae CNCM I-3856

Strategies against the opportunistic fungal pathogen Candida albicans based on probiotic microorganisms represent a promising alternative to traditional antifungals. Here, we investigated the effects of Lactobacillaceae isolates from fermented foods or the human vagina, alone or in combination with the probiotic yeast Saccharomyces cerevisiae CNCM I-3856, against C. albicans in vitro. Nine out of nineteen tested strains of Lactobacillaceae inhibited growth of C. albicans with inhibition zones of 1-3 mm in spot assays. Five out of nineteen lactobacilli tested as such or in combination with S. cerevisiae CNCM I-3856 also significantly inhibited C. albicans hyphae formation, including Limosilactobacillus fermentum LS4 and L. fermentum LS5 resulting in respectively 62% and 78% hyphae inhibition compared to the control. Thirteen of the tested nineteen lactobacilli aggregated with the yeast form of C. albicans, with Lactiplantibacillus carotarum AMBF275 showing the strongest aggregation. The aggregation was enhanced when lactobacilli were combined with S. cerevisiae CNCM I-3856. No significant antagonistic effects were observed between the tested lactobacilli and S. cerevisiae CNCM I-3856. The multifactorial activity of Lactobacillaceae strains alone or combined with the probiotic S. cerevisiae CNCM I-3856 against C. albicans without antagonistic effects between the beneficial strains, paves the way for developing consortium probiotics for in vivo applications.

The Probiotic Kluyveromyces lactis JSA 18 Alleviates Obesity and Hyperlipidemia in High-Fat Diet C57BL/6J Mice

Obesity poses a significant threat to various health conditions such as heart diseases, diabetes, high blood pressure, and heart attack, with the gut microbiota playing a crucial role in maintaining the body's energy balance. We identified a novel probiotic fungal strain, Kluyveromyces lactis JSA 18 (K. lactis), which was isolated from yak milk and was found to possess anti-obesity properties. Additionally, Lactobacillus plantarum CGMCC 8198 (LP8198) from our previous study was also included to evaluate its anti-obesity properties. The findings indicated that K. lactis caused a notable reduction in weight gain, liver and fat indexes, and hyperlipidemia in mice fed a high-fat diet (HFD). Administering K. lactis and LP8198 to mice on a high-fat diet resulted in a reduction of serum triglyceride levels. Furthermore, the supplements reduced ALT and AST activity, and inhibited the production of inflammatory cytokines such as TNF-α and IL-1β. In addition, lipid metabolism was enhanced by the downregulation of ACC1, PPAR-γ, SREBP-1, and Fasn. Moreover, this study found that K. lactis and LP8198 have little effect on gut bacteria. Additionally, K. lactis partially influenced intestinal fungi, while LP8198 had a minor influence on gut mycobiota. The main goal of this research was to show how effective K. lactis can be as a probiotic in combating obesity.

Harnessing the power within: engineering the microbiome for enhanced gynecologic health

Graphical abstract

Abstract

Although numerous studies have demonstrated the impact of microbiome manipulation on human health, research on the microbiome's influence on female health remains relatively limited despite substantial disease burden. In light of this, we present a selected review of clinical trials and preclinical studies targeting both the vaginal and gut microbiomes for the prevention or treatment of various gynecologic conditions. Specifically, we explore studies that leverage microbiota transplants, probiotics, prebiotics, diet modifications, and engineered microbial strains. A healthy vaginal microbiome for females of reproductive age consists of lactic acid-producing bacteria predominantly of the Lactobacillus genus, which serves as a protective barrier against pathogens and maintains a balanced ecosystem. The gut microbiota's production of short-chain fatty acids, metabolism of primary bile acids, and modulation of sex steroid levels have significant implications for the interplay between host and microbes throughout the body, ultimately impacting reproductive health. By harnessing interventions that modulate both the vaginal and gut microbiomes, it becomes possible to not only maintain homeostasis but also mitigate pathological conditions. While the field is still working toward making broad clinical recommendations, the current studies demonstrate that manipulating the microbiome holds great potential for addressing diverse gynecologic conditions.

Lay summary

Manipulating the microbiome has recently entered popular culture, with various diets thought to aid the microbes that live within us. These microbes live in different locations of our body and accordingly help us digest food, modulate our immune system, and influence reproductive health. The role of the microbes living in and influencing the female reproductive tract remains understudied despite known roles in common conditions such as vulvovaginal candidiasis (affecting 75% of females in their lifetime), bacterial vaginosis (25% of females in their lifetime), cervical HPV infection (80% of females in their lifetime), endometriosis (6-10% of females of reproductive age), and polycystic ovary syndrome (10-12% of females of reproductive age). Here, we review four different approaches used to manipulate the female reproductive tract and gastrointestinal system microbiomes: microbiota transplants, probiotics, prebiotics, and dietary interventions, and the use of engineered microbial strains. In doing so, we aim to stimulate discussion on new ways to understand and treat female reproductive health conditions.

Vaginal microbiota: Potential targets for vulvovaginal candidiasis infection

Vulvovaginal candidiasis (VVC) is the second most common cause of vaginal infection globally after bacterial vaginosis (BV) and associated with adverse reproductive and obstetric outcomes, including preterm delivery, sexually transmitted infections and pelvic inflammatory disease. Although effective control of VVC is achievable with the use of traditional treatment strategies (i.e., antifungals), the possibility of drug intolerance, treatment failure and recurrence, as well as the appearance of antifungal-resistant Candida species remain critical challenges. Therefore, alternative therapeutic strategies against VVC are urgently required. In recent years, an improved understanding of the dysbiotic vaginal microbiota (VMB) during VVC has prompted the consideration of administering -biotics to restore the balance of the VMB within the context of VVC prevention and treatment. Here, we aim to summarize the current evidence of the anti-Candida effects of probiotics, postbiotics and synbiotics and their potential use as an alternative/complementary therapy against VVC. Additionally, this review discusses advantages and challenges associated with the application of -biotics in VVC to provide guidance for their later use. We also review new developments in VVC therapy, i.e., vaginal microbiota transplantation (VMT) as an emerging live biotherapeutic therapy against VVC and discuss existing shortcomings associated with this nascent field, expecting to stimulate further investigations for introduction of new therapies against VVC.

Anti-Cariogenic Effects of S. cerevisiae and S. boulardii in S. mutans-C. albicans Cross-Kingdom In Vitro Models

Despite the well-documented health benefits of the probiotic Saccharomyces, its application in oral health has not been comprehensively assessed. Dental caries is a transmissible disease initiated by acid production of cariogenic bacteria and yeast, such as Streptococcus mutans and Candida albicans, on tooth enamel and followed by subsequent enamel demineralization. Here, we investigated the effect of two Saccharomyces strains (Saccharomyces boulardii and Saccharomyces cerevisiae) on S. mutans-C. albicans cross-kingdom interactions using a cariogenic planktonic model. Viable cells, pH changes, and gene expression were measured. S. cerevisiae and S. boulardii inhibited the growth of C. albicans in dual- and multi-species conditions at 4, 6, and 20 h. Saccharomyces also inhibited C. albicans hyphal formation. Furthermore, Saccharomyces reduced the acidity of the culture medium, which usually plummeted below pH 5 when S. mutans and C. albicans were present in the model. The presence of Saccharomyces maintained the culture medium above 6 even after overnight incubation, demonstrating a protective potential against dental enamel demineralization. S. boulardii significantly down-regulated S. mutans atpD and eno gene expression. Overall, our results shed light on a new promising candidate, Saccharomyces, for dental caries prevention due to its potential to create a less cariogenic environment marked by a neutral pH and reduced growth of C. albicans.

Gut microbiota in pathophysiology, diagnosis, and therapeutics of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a multifactorial disease, which is thought to be an interplay between genetic, environment, microbiota, and immune-mediated factors. Dysbiosis in the gut microbial composition, caused by antibiotics and diet, is closely related to the initiation and progression of IBD. Differences in gut microbiota composition between IBD patients and healthy individuals have been found, with reduced biodiversity of commensal microbes and colonization of opportunistic microbes in IBD patients. Gut microbiota can, therefore, potentially be used for diagnosing and prognosticating IBD, and predicting its treatment response. Currently, there are no curative therapies for IBD. Microbiota-based interventions, including probiotics, prebiotics, synbiotics, and fecal microbiota transplantation, have been recognized as promising therapeutic strategies. Clinical studies and studies done in animal models have provided sufficient evidence that microbiota-based interventions may improve inflammation, the remission rate, and microscopic aspects of IBD. Further studies are required to better understand the mechanisms of action of such interventions. This will help in enhancing their effectiveness and developing personalized therapies. The present review summarizes the relationship between gut microbiota and IBD immunopathogenesis. It also discusses the use of gut microbiota as a noninvasive biomarker and potential therapeutic option.

Microbiota Transplant and Gynecological Disorders: The Bridge between Present and Future Treatments

Fecal microbiota transplantation (FMT) is a procedure that involves transferring fecal bacteria from a healthy donor to a patients' intestines to restore gut-immunity homeostasis. While FMT was primarily supposed to treat gastrointestinal disorders such as inflammatory bowel disease and irritable bowel syndrome-and especially Clostridium difficile infection (currently the only used as clinical treatment)-recent research has suggested that it may also become a potential treatment for gynecological disorders, including endometriosis and polycystic ovary syndrome (PCOS). On the contrary, vaginal microbiota transplantation (VMT) is a newer and less commonly used procedure than the FMT approach, and its potential applications are still being explored. It involves direct grafting of the entire vaginal microbiota of healthy women into the vaginal tract of patients to easily rebuild the local microbiota environment, restoring vaginal eubiosis and relieving symptoms. Like FMT, VMT is thought to have potential in treating different microbiota-related conditions. In fact, many gynecological disorders, such as bacterial vaginosis and vulvovaginal candidiasis, are thought to be caused by an imbalance in the vaginal microbiota. In this review, we will summarize the development, current challenges, and future perspectives of microbiota transplant, with the aim of exploring new strategies for its employment as a promising avenue for treating a broad range of gynecological diseases.

Study of Ecological Relationship of Yeast Species with Candida albicans in the Context of Vulvovaginal Infections

The role of the fungal community, the mycobiota, in the health of the vagina is currently an important area of research. The emergence of new sequencing technologies and advances in bioinformatics made possible the discovery of novel fungi inhabiting this niche. Candida spp. constitutes the most important group of opportunistic pathogenic fungi, being the most prevalent fungal species in vulvovaginal infections. However, fungi such as Rhodotorula spp., Naganishia spp. and Malassezia spp. have emerged as potential pathogens in this niche, and therefore it is clinically relevant to understand their ecological interaction with Candida spp. The main aim of this study was to evaluate the impact of yeasts on Candida albicans' pathogenicity, focusing on in-vitro growth, and biofilm formation at different times of co-culture and germ tube formation. The assays were performed with isolated species or with co-cultures of C. albicans (ATCC10231) with one other yeast species: Rhodotorula mucilaginosa (DSM13621), Malassezia furfur (DSM6170) or Naganishia albida (DSM70215). The results showed that M. furfur creates a symbiotic relationship with C. albicans, enhancing the growth rate of the co-culture (149.69%), and of germ tube formation of C. albicans (119.8%) and inducing a higher amount of biofilm biomass of the co-culture, both when mixed (154.1%) and preformed (166.8%). As for the yeasts R. mucilaginosa and N. albida, the relationship is antagonistic (with a significant decrease in all assays), thus possibly repressing the mixture's pathogenicity. These results shed light on the complex interactions between yeasts in the vaginal mycobiome.

The Interplay between Candida albicans, Vaginal Mucosa, Host Immunity and Resident Microbiota in Health and Disease: An Overview and Future Perspectives

Vulvovaginal candidiasis (VVC), which is primarily caused by Candida albicans, is an infection that affects up to 75% of all reproductive-age women worldwide. Recurrent VVC (RVVC) is defined as >3 episodes per year and affects nearly 8% of women globally. At mucosal sites of the vagina, a delicate and complex balance exists between Candida spp., host immunity and local microbial communities. In fact, both immune response and microbiota composition play a central role in counteracting overgrowth of the fungus and maintaining homeostasis in the host. If this balance is perturbed, the conditions may favor C. albicans overgrowth and the yeast-to-hyphal transition, predisposing the host to VVC. To date, the factors that affect the equilibrium between Candida spp. and the host and drive the transition from C. albicans commensalism to pathogenicity are not yet fully understood. Understanding the host- and fungus-related factors that drive VVC pathogenesis is of paramount importance for the development of adequate therapeutic interventions to combat this common genital infection. This review focuses on the latest advances in the pathogenic mechanisms implicated in the onset of VVC and also discusses novel potential strategies, with a special focus on the use of probiotics and vaginal microbiota transplantation in the treatment and/or prevention of recurrent VVC.

Yeasts originating from fermented foods, their potential as probiotics and therapeutic implication for human health and disease

Yeasts derived from fermented foods have historically been known for their organoleptic properties, enriching nutritional values, and producing bioactive metabolites with therapeutic potential. In this review, we discuss the yeast flora in fermented foods, their functional aspects in fermentation, as well as their probiotic and biotherapeutic properties. These yeasts have numerous physical and biochemical characteristics, such as larger cells as compared to bacteria, a rigid cell wall composed primarily of glucans and mannans, natural resistance to antibiotics, and the secretion of secondary metabolites that are both pleasing to the consumer and beneficial to the host's health and well-being. The review also focused on therapeutic applications of probiotic yeasts derived from fermented foods on infections associated with Candida species. These potential probiotic yeasts present an additional avenue to treat dysbiosis of the gut microbiota and prevent health complications that arise from opportunistic fungal colonization, especially drug-resistant superbugs, which are highlighted in this review.

Probiotics in vaginal health

Bacterial vaginosis, a type of vaginal inflammation, can be considered the main reason for abnormal discharges of the vagina and vaginal dysbiosis during reproductive years. Epidemiological investigations of females suffering from vaginitis demonstrated that at least 30% to 50% of all women had Bacterial vaginosis (BV). One of the fields of treatment is the use of probiotics, probiotics are commonly defined as viable microorganisms (yeasts or bacteria) that can positively affect the health of their hosts. They are used in foods, notably fermented milk products, and medicine-related products. The development of new probiotic strains is aimed at more active advantageous organisms. Lactobacillus species are the dominant bacteria in a normal vagina that can decrease the pH of the vagina by the production of lactic acid. A number of lactobacilli types can produce hydrogen peroxide as well. The presence of hydrogen peroxide-induced low pH can prevent the growth of several other microorganisms. The vaginal flora of BV cases can modify by replacing the Lactobacillus species with a high density of anaerobic bacteria (i.e. Mobiluncus sp. Bacteroides sp.), Mycoplasma hominis, and Gardnerella vaginalis. More vaginal infections are treated with medications, while there is a possibility of recurrence and chronic infection because of the adverse effects on the indigenous lactobacilli. Probiotics and prebiotics have shown capacities for optimizing, maintaining, and restoring the vaginal microflora. Therefore, biotherapeutics can offer alternative approaches to reduce infections of the vagina and thus promote consumers' health.

Non-saccharomyces yeast probiotics: revealing relevance and potential

Non-Saccharomyces yeasts are unicellular eukaryotes that play important roles in diverse ecological niches. In recent decades, their physiological and morphological properties have been reevaluated and reassessed, demonstrating the enormous potential they possess in various fields of application. Non-Saccharomyces yeasts have gained relevance as probiotics, and in vitro and in vivo assays are very promising and offer a research niche with novel applications within the functional food and nutraceutical industry. Several beneficial effects have been described, such as antimicrobial and antioxidant activities and gastrointestinal modulation and regulation functions. In addition, several positive effects of bioactive compounds or production of specific enzymes have been reported on physical, mental and neurodegenerative diseases as well as on the organoleptic properties of the final product. Other points to highlight are the multiomics as a tool to enhance characteristics of interest within the industry; as well as microencapsulation offer a wide field of study that opens the niche of food matrices as carriers of probiotics; in turn, non-Saccharomyces yeasts offer an interesting alternative as microencapsulating cells of various compounds of interest.

Similarities and Differences among Species Closely Related to Candida albicans: C. tropicalis, C. dubliniensis, and C. auris

Although Candida species are widespread commensals of the microflora of healthy individuals, they are also among the most important human fungal pathogens that under certain conditions can cause diseases (candidiases) of varying severity ranging from mild superficial infections of the mucous membranes to life-threatening systemic infections. So far, the vast majority of research aimed at understanding the molecular basis of pathogenesis has been focused on the most common species—Candida albicans. Meanwhile, other closely related species belonging to the CTG clade, namely, Candida tropicalis and Candida dubliniensis, are becoming more important in clinical practice, as well as a relatively newly identified species, Candida auris. Despite the close relationship of these microorganisms, it seems that in the course of evolution, they have developed distinct biochemical, metabolic, and physiological adaptations, which they use to fit to commensal niches and achieve full virulence. Therefore, in this review, we describe the current knowledge on C. tropicalis, C. dubliniensis, and C. auris virulence factors, the formation of a mixed species biofilm and mutual communication, the environmental stress response and related changes in fungal cell metabolism, and the effect of pathogens on host defense response and susceptibility to antifungal agents used, highlighting differences with respect to C. albicans. Special attention is paid to common diagnostic problems resulting from similarities between these species and the emergence of drug resistance mechanisms. Understanding the different strategies to achieve virulence, used by important opportunistic pathogens of the genus Candida, is essential for proper diagnosis and treatment.

Interactions between Candida albicans and the resident microbiota

Candida albicans is a prevalent, opportunistic human fungal pathogen. It usually dwells in the human body as a commensal, however, once in its pathogenic state, it causes diseases ranging from debilitating superficial to life-threatening systemic infections. The switch from harmless colonizer to virulent pathogen is, in most cases, due to perturbation of the fungus-host-microbiota interplay. In this review, we focused on the interactions between C. albicans and the host microbiota in the mouth, gut, blood, and vagina. We also highlighted important future research directions. We expect that the evaluation of these interplays will help better our understanding of the etiology of fungal infections and shed new light on the therapeutic approaches.

Impacts of Menstruation, Community Type, and an Oral Yeast Probiotic on the Vaginal Microbiome

How to define and promote a healthy state of the vaginal microbiome is not well understood. Knowledge of which underlying factors shape the microbial community composition of the vagina and how to modulate them will contribute to vaginal disease prevention and improve fertility.

Oral Fluconazole Therapy in Patients With Active Ulcerative Colitis Who Have Detectable Candida in the Stool : A Double-Blind Randomized Placebo-controlled Trial

BACKGROUND

There is an emerging role of fungal dysbiosis in the pathogenesis of inflammatory bowel disease. Prevalence of Candida in patients with active ulcerative colitis (UC) and the effect of fluconazole therapy in reducing disease activity of UC are not known.

PATIENTS AND METHODS

All consecutive consenting patients with active UC defined as Mayo score ≥3 were evaluated for presence of Candida by stool culture and predictors for presence of Candida were identified. Those who had evidence of Candida in the stool were randomized to receive oral fluconazole 200 mg daily or placebo for 3 weeks along with standard medical therapy. Patients were assessed by clinical, sigmoidoscopy, and laboratory parameters at baseline and at 4 weeks. The primary outcome was clinical and endoscopic response at 4 weeks defined by a 3-point reduction in Mayo score. Secondary outcomes were reduction in fecal calprotectin, histologic response, and adverse events.

RESULTS

Of the 242 patients with active UC, 68 (28%) patients had Candida in stool culture. Independent predictors for presence of Candida in patients with active UC were partial Mayo score of ≥3 and steroid exposure. Among those with Candida on stool culture (n=68), 61 patients fulfilled eligibility criteria and were randomized to receive fluconazole (n=31) or placebo (n=30). Three-point reduction in Mayo score though was numerically higher in the fluconazole group than the placebo group but was not statistically significant [5 (16.1%) vs. 1 (3.33%); P =0.19]. Postintervention median Mayo score was lower in fluconazole than placebo group [4 (3, 5) vs. 5 (4, 6); P =0.034]. Patients in fluconazole group had more often reduction in fecal calprotectin [26 (83.9%) vs. 11 (36.7%); P =0.001] and histologic scores [23 (74.1%) vs. 10 (33.3%); P =0.001] compared with placebo. All patients were compliant and did not report any serious adverse event.

CONCLUSION

Candida colonization is found in 28% of patients with UC. Steroid exposure and active disease were independent predictors for the presence of Candida . There was no statistically significant difference in the number of patients who achieved 3-point reduction in Mayo score between 2 groups. However, clinical, histologic, and calprotectin levels showed significant improvement in fluconazole group.

Immunoprotective Effects of Two Histone H2A Variants in the Grass Carp Against Flavobacterium columnare Infection

In teleost fish, the nucleotide polymorphisms of histone H2A significantly affect the resistance or susceptibility of zebrafish to Edwardsiella piscicida infection. Whether histone H2A variants can enhance the resistance of grass carp to Flavobacterium columnare infection remains unclear. Here, the effects of 7 previously obtained variants (gcH2A-1~gcH2A-7) and 5 novel histone H2A variants (gcH2A-11, gcH2A-13~gcH2A-16) in response to F. columnare infection were investigated. It was found that these histone H2A variants could be divided into type I and II. Among them, 5 histone H2A variants had no any effects on the F. columnare infection, however 7 histone H2A variants had antibacterial activity against F. columnare infection. The gcH2A-4 and gcH2A-11, whose antibacterial activity was the strongest in type I and II histone H2A variants respectively, were picked out for yeast expression. Transcriptome data for the samples from the intestines of grass carp immunized with the engineered Saccharomyces cerevisiae expressing PYD1, gcH2A-4 or gcH2A-11 revealed that 5 and 12 immune-related signaling pathways were significantly enriched by gcH2A-4 or gcH2A-11, respectively. For the engineered S. cerevisiae expressing gcH2A-4, NOD-like receptor and Toll-like receptor signaling pathways were enriched for up-regulated DEGs. Besides NOD-like receptor and Toll-like receptor signaling pathways, the engineered S. cerevisiae expressing gcH2A-11 also activated Cytosolic DNA-sensing pathway, RIG-I-like receptor signaling pathway and C-type lectin receptor signaling pathway. Furthermore, grass carp were immunized with the engineered S. cerevisiae expressing PYD1, gcH2A-4 or gcH2A-11 for 1 month and challenged with F. columnare. These grass carp immunized with gcH2A-4 or gcH2A-11 showed lower mortality and fewer numbers of F. columnare than did the control group. All these results suggest that gcH2A-4 and gcH2A-11 play important roles in evoking the innate immune responses and enhancing disease resistance of grass carp against F. columnare infection.

In Vitro Characterization and Identification of Potential Probiotic Yeasts Isolated from Fermented Dairy and Non-Dairy Food Products

This study is about the isolation of yeast from fermented dairy and non-dairy products as well as the characterization of their survival in in vitro digestion conditions and tolerance to bile salts. Promising strains were selected to further investigate their probiotic properties, including cell surface properties (autoaggregation, hydrophobicity and coaggregation), physiological properties (adhesion to the HT-29 cell line and cholesterol lowering), antimicrobial activities, bile salt hydrolysis, exopolysaccharide (EPS) producing capability, heat resistance and resistance to six antibiotics. The selected yeast isolates demonstrated remarkable survivability in an acidic environment. The reduction caused by in vitro digestion conditions ranged from 0.7 to 2.1 Log₁₀. Bile salt tolerance increased with the extension in the incubation period, which ranged from 69.2% to 91.1% after 24 h. The ability of the 12 selected isolates to remove cholesterol varied from 41.6% to 96.5%, and all yeast strains exhibited a capability to hydrolyse screened bile salts. All the selected isolates exhibited heat resistance, hydrophobicity, strong coaggregation, autoaggregation after 24 h, robust antimicrobial activity and EPS production. The ability to adhere to the HT-29 cell line was within an average of 6.3 Log₁₀ CFU/mL after 2 h. Based on ITS/5.8S ribosomal DNA sequencing, 12 yeast isolates were identified as 1 strain for each Candidaalbicans and Saccharomyces cerevisiae and 10 strains for Pichia kudriavzevii.

Probiotic Yeast Saccharomyces: Back to Nature to Improve Human Health

Saccharomyces cerevisiae var. boulardii is best known for its treatment efficacy against different gastrointestinal diseases. This probiotic yeast can significantly protect the normal microbiota of the human gut and inhibit the pathogenicity of different diarrheal infections. Several clinical investigations have declared S. cerevisiae var. boulardii a biotherapeutic agent due to its antibacterial, antiviral, anti-carcinogenic, antioxidant, anti-inflammatory and immune-modulatory properties. Oral or intramuscular administration of S. cerevisiae var. boulardii can remarkably induce health-promoting effects in the host body. Different intrinsic and extrinsic factors are responsible for its efficacy against acute and chronic gut-associated diseases. This review will discuss the clinical and beneficial effects of S. cerevisiae var. boulardii in the treatment and prevention of different metabolic diseases and highlight some of its health-promising properties. This review article will provide fundamental insights for new avenues in the fields of biotherapeutics, antimicrobial resistance and one health.

Gut microbiota and inflammatory bowel disease

Gut microbiota refers to the complex aggregation of microbes in gut, including bacteria, archaea, fungi, and viruses, and they exert marked influence on the host's health. Perturbations in the gut microbiota have been closely linked to initiation and progression of IBD, which has become a disease with accelerating incidence worldwide, but it remains to be thoroughly investigated how microbial involvement might contribute to IBD. In this review, we discuss the current research findings concerning alterations in the gut microbiota, trans-kingdom interaction between the members of the gut microbiota, their interactions with the immune system of host, their potential role in the IBD pathogenesis, and the relationship between gut microbiota and IBD. We hope to provide a better understanding of the causes of IBD and shed light on the development of microbiome-based therapeutic approaches, which might be a promising strategy to alleviate, manage, and eventually cure IBD. This article is categorized under: Infectious Diseases > Genetics/Genomics/Epigenetics Infectious Diseases > Molecular and Cellular Physiology.

The Use of Probiotics for Management and Improvement of Reproductive Eubiosis and Function

Reproductive tract dysbiosis, due to the action of pathogens and/or unhealthy lifestyle, has been related to many reproductive diseases and disorders in mammalian species. Classically, such a problem has been confronted by the administration of antibiotics. Despite their effectiveness for controlling disease, treatments with antibiotics may negatively affect the fertility of males and females and, mainly, may induce antibiotic resistance. Accordingly, safer alternatives for maintaining reproductive system eubiosis, such as probiotics, are required. The present review summarizes the current knowledge on the biodiversity of the microbiota at the reproductive tract, possible changes in the case of dysbiosis, and their relationships with adequate reproductive health and functioning in both females and males. Afterwards, mechanisms of action and benefits of different probiotics are weighed since the biological activities of probiotics may provide a promising alternative to antibiotics for maintaining and restoring reproductive eubiosis and function. However, at present, it is still necessary for further research to focus on: (a) identifying mechanisms by which probiotics can affect reproductive processes; (b) the safety of probiotics to the host, specifically when consumed during sensitive reproductive windows such as pregnancy; and (c) the hazards instructions and regulatory rules required for marketing these biological-based therapies with sufficient safety. Thus, in this review, to draw a comprehensive overview with a relatively low number of clinical studies in this field, we showed the findings of studies performed either on human or animal models. This review strategy may help provide concrete facts on the eligible probiotic strains, probiotics colonization and transfer route, and prophylactic and/or therapeutic effects of different probiotic strains.

Virulence Factors as Promoters of Chronic Vulvovaginal Candidosis: A Review

INTRODUCTION

The vast majority of the species of the genus Candida spp. is commensal in humans; however, some are opportunistic pathogens that can cause infection, called candidosis. Among the different types of candidosis, we highlight the vulvovaginal (VVC) which can occur in two main clinical variants: chronic (cVVC) and episodic or sporadic. The incidence of cVVC has been worrying the scientific community, promoting the research on genotypic and phenotypic causes of its occurrence. We summarize important findings on factors that favor chronic vulvovaginal candidosis with respect to molecular epidemiology and the expression of various virulence factors, while clarifying the terminology involving these infections.

AIM AND METHODOLOGY

The aim of this review was to gather research that linked virulence factors to VVC and its persistence and recurrence, using two databases (Pubmed and Google Scholar). Predisposing factors in women for the occurrence of cVVC and some studies that refer new preventive and alternative therapies were also included, where appropriate.

RESULTS AND DISCUSSION

Several studies have been shedding light on the increasing number of persistence and recurrences of VVC. The expression of virulence factors has been related to both chronic forms of VVC and antifungal resistance. Other studies report mutations occurring in the genome of Candida spp. during the infection phase which may be important indications for new therapies. The introduction of preventive therapies and new therapies has revealed great importance and is also highlighted here.

Secondary Metabolites from Food-Derived Yeasts Inhibit Virulence of Candida albicans

A sparse number of available antifungal drugs, therapeutic side effects, and drug resistance are major challenges in current antifungal therapy to treat Candida albicans-associated infections. Here, we describe two food-derived yeasts, Saccharomyces cerevisiae and Issatchenkia occidentalis, that inhibit virulence traits of C. albicans, including hyphal morphogenesis, biofilm formation, and adhesion to intestinal epithelial cells. These yeasts also protect the model host Caenorhabditis elegans from C. albicans infection. We demonstrate that the protective activity is primarily retained in the secretome of the beneficial yeasts, and the protection they provide as a physical barrier is negligible. S. cerevisiae aro8 aro9 mutant analysis demonstrate that phenylethanol and tryptophol are necessary for protection, and experiments with commercially procured compounds indicate that they are sufficient to inhibit C. albicans virulence. We propose food-derived yeasts as an alternative or combination therapy to conventional antifungal therapy for C. albicans infection. IMPORTANCE The gut microbiome, primarily established by food, is complex and contributes to the health of the host. Molecular mechanisms that regulate microbial interactions and host health remain unclear. Here, we show that the pathogen C. albicans interacts with food-derived beneficial yeasts in the gut of the microscopic worm, C. elegans, forming a simple microbiome. C. albicans can colonize the worm gut, compromising the worm's health, and exposure to the food-derived yeasts ameliorates this effect protecting the nematode host. We identify small molecules from food-derived yeasts that are necessary and sufficient to inhibit multiple virulence traits of C. albicans and protect the nematode host. The nematode gut faithfully recapitulates a mammalian intestine. This could be an effective alternative or combination therapy for C. albicans infection.

The Role of Fatty Acid Metabolites in Vaginal Health and Disease: Application to Candidiasis

Although the vast majority of women encounters at least one vaginal infection during their life, the amount of microbiome-related research performed in this area lags behind compared to alternative niches such as the intestinal tract. As a result, effective means of diagnosis and treatment, especially of recurrent infections, are limited. The role of the metabolome in vaginal health is largely elusive. It has been shown that lactate produced by the numerous lactobacilli present promotes health by limiting the chance of infection. Short chain fatty acids (SCFA) have been mainly linked to dysbiosis, although the causality of this relationship is still under debate. In this review, we aim to bring together information on the role of the vaginal metabolome and microbiome in infections caused by Candida. Vulvovaginal candidiasis affects near to 70% of all women at least once in their life with a significant proportion of women suffering from the recurrent variant. We assess the role of fatty acid metabolites, mainly SCFA and lactate, in onset of infection and virulence of the fungal pathogen. In addition, we pinpoint where lack of research limits our understanding of the molecular processes involved and restricts the possibility of developing novel treatment strategies.

The promising biological role of postbiotics derived from probiotic Lactobacillus species in reproductive health

Recent investigations have meaningfully developed our knowledge of the features of the reproductive microbiome/metabolome profile and their relations with host responses to offer an optimal milieu for the development of the embryo during the peri-implantation period and throughout pregnancy. In this context, the establishment of homeostatic circumstances in the Female Reproductive Tract (FRT), in various physiological periods, is a significant challenge, which appears the application of postbiotics can facilitate the achievement of this goal. So, currently, scientific literature confirms that postbiotics due to their antimicrobial, antiviral, and immunomodulatory properties can be considered as a novel biotherapeutic approach. Future investigation in this field will shed more translational mechanistic understanding of the interaction of the postbiotics derived from vaginal Lactobacilli with females' health and reproduction.

It Takes Two to Tango: How a Dysregulation of the Innate Immunity, Coupled With Candida Virulence, Triggers VVC Onset

Vulvovaginal candidiasis (VVC) is a symptomatic inflammation of the vagina mainly caused by C. albicans. Other species, such as C. parapsilosis, C. glabrata, C. tropicalis, and C. krusei, are mainly associated to the recurrent form of the disease (RVVC), although with a lower frequency. In its yeast form, C. albicans is tolerated by the vaginal epithelium, but switching to the invasive hyphal form, co-regulated with the expression of genes encoding virulence factors such as secreted aspartyl proteases (Sap) and candidalysin, allows for tissue damage. Vaginal epithelial cells play an important role by impairing C. albicans tissue invasion through several mechanisms such as epithelial shedding, secretion of mucin and strong interepithelial cell connections. However, morphotype switching coupled to increasing of the fungal burden can overcome the tolerance threshold and trigger an intense inflammatory response. Pathological inflammation is believed to be facilitated by an altered vaginal microbiome, i.e., Lactobacillus dysbiosis. Notwithstanding the damage caused by the fungus itself, the host response to the fungus plays an important role in the onset of VVC, exacerbating fungal-mediated damage. This response can be triggered by host PRR-fungal PAMP interaction and other more complex mechanisms (i.e., Sap-mediated NLRP3 activation and candidalysin), ultimately leading to strong neutrophil recruitment. However, recruited neutrophils appear to be ineffective at reducing fungal burden and invasion; therefore, they seem to contribute more to the symptoms associated with vaginitis than to protection against the disease. Recently, two aspects of the vulvovaginal environment have been found to associate with VVC and induce neutrophil anergy in vitro: perinuclear anti-neutrophil cytoplasmic antibodies (pANCA) and heparan sulfate. Interestingly, CAGTA antibodies have also been found with higher frequency in VVC as compared to asymptomatic colonized women. This review highlights and discusses recent advances on understanding the VVC pathogenesis mechanisms as well as the role of host defenses during the disease.

Application of probiotics in candidiasis management

Candidiasis (e.g., oral, gastrointestinal, vaginal, urinary tract, systemic) is a worldwide growing problem, since antifungal resistance and immunosuppression states are rising. To address this problem, very few drugs are available for the treatment of Candida spp. infections. Therefore, novel therapeutic strategies are urgently required. Probiotics have been proposed for the prevention and treatment of bacterial infections due to their safety record and efficacy, however, little is still known about their potential role regarding fungal infections. The purpose of this review is to present an updated summary of the evidence of the antifungal effects of probiotics along with a discussion of their potential use as an alternative/complementary therapy against Candida spp. infections. Thus, we performed a literature search using appropriate keywords ("Probiotic + Candida", "Candidiasis treatment", and "Probiotic + candidiasis") to retrieve relevant studies (both preclinical and clinical) with special emphasis on the works published in the last 5 years. An increasing amount of evidence has shown the potential usefulness of probiotics in the management of oral and vulvovaginal candidiasis in recent years. Among other results, we found that, as for bacterial infections, Lactobacillus, Bifidobacterium, and Saccharomyces are the most studied and effective genus for this purpose. However, in other areas, particularly in skincandidiaisis, studies are low or lacking. Thus, further investigation is necessary including in vitro and in vivo studies to establish the usefulness of probiotics in the management of candidiasis.

Heat inactivation partially preserved barrier and immunomodulatory effects of Lactobacillus gasseri LA806 in an in vitro model of bovine mastitis

Probiotics could help combat infections and reduce antibiotic use. As use of live bacteria is limited in some cases by safety or regulatory concerns, the potential of inactivated bacteria is worth investigating. We evaluated the potential of live and heat-inactivated Lactobacillus gasseri LA806 to counteract Staphylococcus aureus and Escherichia coli infection cycles in an in vitro model of bovine mastitis. We assessed the ability of live and inactivated LA806 to impair pathogen colonisation of bovine mammary epithelial cells (bMECs) and to modulate cytokine expression by pathogen-stimulated bMECs. Live LA806 induced a five-fold decrease in S. aureus adhesion and internalisation (while not affecting E. coli colonisation) and decreased pro-inflammatory cytokine expression by S. aureus-stimulated bMECs (without interfering with the immune response to E. coli). The ability of inactivated LA806 ability to diminish S. aureus colonisation was two-fold lower than that of the live strain, but its anti-inflammatory properties were barely impacted. Even though LA806 effects were impaired after inactivation, both live and inactivated LA806 have barrier and immunomodulatory properties that could be useful to counteract S. aureus colonisation in the bovine mammary gland. As S. aureus is involved in various types of infection, LA806 potential would worth exploring in other contexts.

Selenization of S. cerevisiae increases its protective potential in experimental autoimmune encephalomyelitis by triggering an intestinal immunomodulatory loop

Multiple sclerosis is an autoimmune disease that affects the myelinated central nervous system (CNS) neurons and triggers physical and cognitive disabilities. Conventional therapy is based on disease-modifying drugs that control disease severity but can also be deleterious. Complementary medicines have been adopted and evidence indicates that yeast supplements can improve symptoms mainly by modulating the immune response. In this investigation, we evaluated the therapeutic potential of Saccharomyces cerevisiae and its selenized derivative (Selemax) in experimental autoimmune encephalomyelitis (EAE). Female C57BL/6 mice submitted to EAE induction were orally supplemented with these yeasts by gavage from day 0 to day 14 after EAE induction. Both supplements determined significant reduction in clinical signs concomitantly with diminished Th1 immune response in CNS, increased proportion of Foxp3⁺ lymphocytes in inguinal and mesenteric lymph nodes and increased microbiota diversity. However, Selemax was more effective clinically and immunologically; it reduced disease prevalence more sharply, increased the proportion of CD103⁺ dendritic cells expressing high levels of PD-L1 in mesenteric lymph nodes and reduced the intestinal inflammatory process more strongly than S. cerevisiae. These results suggest a clear gut-brain axis modulation by selenized S. cerevisiae and suggest their inclusion in clinical trials.

Effect of probiotic bacteria on oral Candida in head- and neck-radiotherapy patients: A randomized clinical trial

Objective

The aim of the study is to assess the effect of probiotic bacteria on oral Candida counts in cancer patients who are undergoing head- and neck-radiotherapy in a tertiary care center.

Study Design

The study was a randomized clinical trial including 90 patients who just completed head- and neck-radiotherapy.

Materials and Methods

Participants were randomly allocated into three equal sized groups, i.e., probiotics group, candid group, and combination groups. Oral rinse samples of the patients were collected before and after the intervention for the identification of Candida. The samples were incubated on Sabouraud's Dextrose Agar with Chloramphenicol at 37°C for 48 h, to assess the counts of colony-forming units/milliliter (CFU/ml) of Candida in saliva, and further on chrome agar plates to identify the Candida spp. Data were analyzed using mixed ANOVA to compare mean CFU/ml of Candida among three groups before and after the intervention.

Results

A total of 86 patients were included in the final analysis and there was a statistically significant reduction in mean Candida spp. Counts (CFU/ml) after intervention in all the three groups (P = 0.000) and significant reductions identified in both probiotic and combination therapy groups. Apart from reduction in Candida albicans, significant decrease in Candida glabrata and Candida tropicalis was observed after probiotics usage compared to other groups.

Conclusions

The present study suggests that probiotic bacteria were effective in reducing oral Candida spp which can be recommended alone or in combination with traditional antifungal agents for effective reduction in oral Candida in head- and neck-radiotherapy patients.

Application of Probiotic Yeasts on Candida Species Associated Infection

Superficial and life-threatening invasive Candida infections are a major clinical challenge in hospitalized and immuno-compromised patients. Emerging drug-resistance among Candida species is exacerbated by the limited availability of antifungals and their associated side-effects. In the current review, we discuss the application of probiotic yeasts as a potential alternative/ combination therapy against Candida infections. Preclinical studies have identified several probiotic yeasts that effectively inhibit virulence of Candida species, including Candida albicans, Candida tropicalis, Candida glabrata, Candida parapsilosis, Candida krusei and Candida auris. However, Saccharomyces cerevisiae var. boulardii is the only probiotic yeast commercially available. In addition, clinical studies have further confirmed the in vitro and in vivo activity of the probiotic yeasts against Candida species. Probiotics use a variety of protective mechanisms, including posing a physical barrier, the ability to aggregate pathogens and render them avirulent. Secreted metabolites such as short-chain fatty acids effectively inhibit the adhesion and morphological transition of Candida species. Overall, the probiotic yeasts could be a promising effective alternative or combination therapy for Candida infections. Additional studies would bolster the application of probiotic yeasts.

Anti-Biofilm Properties of Saccharomyces cerevisiae CNCM I-3856 and Lacticaseibacillus rhamnosus ATCC 53103 Probiotics against G. vaginalis

Bacterial vaginosis (BV) is characterized by the presence of a polymicrobial biofilm where Gardnerella vaginalis plays a key role. Previously, we demonstrated that Saccharomyces cerevisiae CNCM (French National Collection of Cultures of Microorganisms) I-3856 is helpful in resolving experimental simulated BV in mice. In this study, we analyzed its capacity to affect G. vaginalis biofilms and to potentiate the activity of standard antimicrobial agents. We also investigated the anti-biofilm activity of Lacticaseibacillus rhamnosus GG (ATCC 53103), a well-known strain for its intestinal healthy benefits. Biofilm biomass was assessed by crystal violet staining, and G. vaginalis viability was assessed by a colony forming unit (CFU) assay. Here, for the first time, we demonstrated that S. cerevisiae CNCM I-3856 as well as L. rhamnosus GG were able (i) to significantly inhibit G. vaginalis biofilm formation, (ii) to markedly reduce G. vaginalis viability among the biomass constituting the biofilm, (iii) to induce disaggregation of preformed biofilm, and (iv) to kill a consistent amount of bacterial cells in a G. vaginalis preformed biofilm. Furthermore, S. cerevisiae CNCM I-3856 strongly potentiates the metronidazole effect on G. vaginalis biofilm viability. These results suggest that S. cerevisiae CNCM I-3856 as well as L. rhamnosus GG could be potential novel therapeutic agents against bacterial vaginosis.

Recovery of Saccharomyces cerevisiae CNCM I-3856 in Vaginal Samples of Healthy Women after Oral Administration

Bacterial vaginosis and vulvovaginal candidiasis are common causes of impaired health and quality of life for women. Although antimicrobial agents remain the main strategy for the treatment of vaginal infections, their repeated use involves high rates of resistance and recurrence. Alternative approaches such as probiotics are studied. Saccharomyces cerevisiae CNCM I-3856 already demonstrated beneficial effects in experimental models of vaginal infections. This randomized, double-blind, placebo-controlled clinical study was performed to evaluate the recovery of S. cerevisiae CNCM I-3856 in vaginal samples in healthy women after oral consumption. Sixty healthy women were randomized to receive a daily dose of S. cerevisiae CNCM I-3856 or a placebo for 4 weeks. Subcultures and quantitative polymerase chain reaction (qPCR) were used to detect the strain in vaginal and stool samples. A safety assessment was carried out throughout the study. Fifty-seven women completed the study. Over the 4-week supplementation phase, S. cerevisiae CNCM I-3856 has been detected in the vaginal samples of 21% of women (n = 4/19) in the 500 mg Probiotic group and 16% of women (n = 3/19) in the 1000 mg Probiotic group. The strain was detected in the faeces of 90% of women consuming the probiotic. This is the first clinical study demonstrating the migration of yeast from intestine to vagina where it may exert its benefits.

Vaginal Epithelial Cells Discriminate Between Yeast and Hyphae of Candida albicans in Women Who Are Colonized or Have Vaginal Candidiasis

BACKGROUND

Vaginal candidiasis is common disease affecting women; however, how Candida albicans shift from commensalism towards a pathogenic status remains poorly understood. The present study investigated the vaginal epithelial cell (EC) response dynamics under various conditions.

METHODS

Healthy women, asymptomatic C. albicans carriers, and symptomatic patients with vaginal candidiasis were enrolled in this study. ECs in vaginal swabs were analyzed with cytofluorimetric analysis for pattern recognition receptors and intracellular signals, with lactate dehydrogenase assay performed for cell damage, and an enzyme-linked immunosorbent assay for cytokine expression.

RESULTS

The level of toll-like receptor 4 (TLR4), TLR2, and erythropoietin-producing hepatoma A2 (EphA2) expression was significantly higher in ECs from asymptomatic and symptomatic subjects compared to healthy subjects. Activation of transcription factors, nuclear factor-κB (NF-κB) and c-Fos-p-38, was observed in ECs from symptomatic and asymptomatic pseudohyphae/hyphae carriers but not from the asymptomatic yeast carriers. EC damage was only observed in symptomatic patients.

CONCLUSIONS

The presence of pseudohyphae/hyphae is required to determine vaginal candidiasis; however, it may be not sufficient to induce the pathologic process associated with neutrophil recruitment and EC damage. This study sheds light on the ambiguous role of the hyphal form during vaginal human commensalism.

Saccharomyces cerevisiae-Based Probiotics as Novel Antimicrobial Agents to Prevent and Treat Vaginal Infections

Vaginal infections affect 70% of women during their lifetimes and account for millions of annual doctors’ visits. These infections are predominantly represented by vulvovaginal candidiasis (VVC) and bacterial vaginosis (BV). Although standard antimicrobial agents remain the major strategy for the prevention and treatment of vaginal infections, both VVC and BV are difficult to treat due to high rates of resistance and recurrence, high probability of complications, and negative effects on the vaginal microbiota. This review focuses on a new approach of yeast-based probiotics for the prevention and/or treatment of these common vaginal infections.

Vulvovaginal Candidiasis: A Current Understanding and Burning Questions

Candida albicans, along with other closely related Candida species, are the primary causative agents of vulvovaginal candidiasis (VVC)-a multifactorial infectious disease of the lower female reproductive tract resulting in pathologic inflammation. Unlike other forms of candidiasis, VVC is a disease of immunocompetent and otherwise healthy women, most predominant during their child-bearing years. While VVC is non-lethal, its high global incidence and profound negative impact on quality-of-life necessitates further understanding of the host and fungal factors that drive disease pathogenesis. In this review, we cover the current state of our understanding of the epidemiology, host response, fungal pathogenicity mechanisms, impact of the microbiome, and novel approaches to treatment of this most prevalent human candidal infection. We also offer insight into the latest advancements in the VVC field and identify important questions that still remain.

Apoptosis of vaginal epithelial cells in clinical samples from women with diagnosed bacterial vaginosis

Bacterial vaginosis (BV) is one of the most common vaginal infections among women of childbearing age. Gardnerella vaginalis (G. vaginalis) is a keystone microorganism present in more than 95% of all BV cases. The first step of the infection process in BV is mediated by interaction of microorganisms with epithelial cells (ECs). However, the role of these cells in BV pathogenesis is largely unknown. The present study aimed to investigate the vaginal EC response during BV. Twenty healthy women and 34 women with BV were enrolled in this study. The number of ECs in the vaginal swab was counted and analyzed for intracellular signals and apoptosis by flow cytometry. Cell damage was evaluated by lactate dehydrogenase assay. Compared to that in healthy donors, the percentage of exfoliated vaginal ECs was increased in women with BV, and an absence of neutrophils was observed in both groups. Activation signals, such as p-IκBα and c-Fos were unmodulated in the vaginal ECs of women with BV. Moreover, EC damage and apoptosis were significantly increased in patients with BV. Apoptosis was related to caspase-3 activation and the presence of G. vaginalis. This study provides the first evidence of a direct involvement of G. vaginalis in the apoptotic process of vaginal ECs during BV. This effect was mediated by caspase-3 activation, and G. vaginalis appeared to be one of causes for inducing EC apoptosis in BV. Hence, our findings suggest a possible explanation for the increased exfoliation of ECs in the vagina during BV.

Yeast a potential bio-agent: future for plant growth and postharvest disease management for sustainable agriculture

The native microbial flora and fauna are replaced by commercial chemical fertilizers and pesticides, in the current agricultural system. Imbalance of beneficial microbial diversity and natural competitors increases the severity of plant diseases. Hence, sustainable agricultural practices like bio-inoculant, stress tolerant consortium, crop rotation and mix cropping sequences is only the solution of recharging the microbial population in soils to make healthier for crop productivity and suppression of soil borne phytopathogen. Microorganisms use several direct mechanism activities, e.g. production of plant hormones (indole-3-acetic acid), ammonium, siderophore and nutrient solubilization, and indirect mechanism activities, e.g. hydrogen cyanide, chitinase, protease and antibiotic for plant growth promotion. The plant growth-promoting effect of bacteria, fungi, mycorrhizal fungi and algae is widely explored. Yeast is a single-celled microbe classified as members of the kingdom fungi. Yeast and their product use in the food industry, medical science and biotechnological research purpose but very few literatures reported that yeasts have the ability to produce a group of plant growth-promoting activities and biocontrolling activity. Therefore, the main aim of this mini review is to highlight the application of yeasts as biological agents in different sectors of sustainable farming practices.

Review article: fungal alterations in inflammatory bowel diseases

BACKGROUND

Emerging data suggest that alterations in gut fungi may be associated with the pathogenesis of inflammatory bowel disease (IBD). In healthy individuals, gut commensal fungi act synergistically with other members of the microbiota to maintain homeostasis but their role in IBD is less clear.

AIM

To review the role of gut fungi and their trans-kingdom interactions with bacteria in IBD METHODS: A literature search was conducted on Ovid and Pubmed to select relevant animal and human studies that have reported fungi and IBD.

RESULTS

There is an increased total fungal load particularly of Candida and Malassezia species in the faeces and mucosa of Crohn's disease patients, and a lower fungal diversity in the faeces of ulcerative colitis patients. Caspase recruitment domain-containing protein (CARD)-9 polymorphism in Crohn's disease patients favours Malassezia colonisation that worsens gut inflammation. Diet high in carbohydrates increased the total abundance of Candida species, whereas protein-rich diet had the opposite effect. Anti-fungal therapies are mostly used to treat Candida albicans or Histoplasma capsulatum infections in IBD, whereas pilot studies of supplementing fungal probiotics Saccharomycopsis fibuligera, Saccharomyces boulardii and Saccharomyces cerevisiae CNCM I-3856 strain showed therapeutic effects in IBD.

CONCLUSIONS

Gut fungi are altered in patients with Crohn's disease and ulcerative colitis. Modulation of the fungal microbiota can be considered as a therapeutic approach for IBD. Future research should focus on understanding how the fungal microbiota interacts with other components of the gut microbiota in association with the pathogenesis and development of IBD.

A Role for Yeast/Pseudohyphal Cells of Candida albicans in the Correlated Expression of NLRP3 Inflammasome Inducers in Women With Acute Vulvovaginal Candidiasis

In acute vulvovaginal candidiasis (VVC), the fungus Candida albicans activates inflammasome receptors of vaginal epithelial cells through the production of virulence and immuno-inflammatory factors. Here, we show that in VVC patients, genes encoding some of the above factors (SAP2, SAP5, SAP6, ECE1, and HWP1) are expressed in a correlated fashion. Cytological observations pointed out that pseudohyphal filaments with yeast cells are dominant at the acidic vaginal pH, and this is coupled with co-expression, at roughly similar level, of SAP2, a typical yeast and ECE1, a typical hyphae-associated genes. In contrast, vigorous hyphal growth dominated at the neutral vaginal pH of mice experimentally infected with C. albicans isolates from VVC subjects, and this is coupled with a high ratio of ECE1 to SAP2 expression. We suggest that the pseudohyphal rather than true hyphal cells of C. albicans play a critical role in VVC, possibly through the activity of multiple inflammasome inducers.

Probiotic Yeasts Inhibit Virulence of Non-albicans Candida Species

Systemic infections of Candida species pose a significant threat to public health. Toxicity associated with current therapies and emergence of resistant strains present major therapeutic challenges. Here, we report exploitation of the probiotic properties of two novel, food-derived yeasts, Saccharomyces cerevisiae (strain KTP) and Issatchenkia occidentalis (strain ApC), as an alternative approach to combat widespread opportunistic fungal infections. Both yeasts inhibit virulence traits such as adhesion, filamentation, and biofilm formation of several non-albicans Candida species, including Candida tropicalis, Candida krusei, Candida glabrata, and Candida parapsilosis as well as the recently identified multidrug-resistant species Candida auris They inhibit adhesion to abiotic surfaces as well as cultured colon epithelial cells. Furthermore, probiotic treatment blocks the formation of biofilms of individual non-albicans Candida strains as well as mixed-culture biofilms of each non-albicans Candida strain in combination with Candida albicans The probiotic yeasts attenuated non-albicans Candida infections in a live animal. In vivo studies using Caenorhabditis elegans suggest that exposure to probiotic yeasts protects nematodes from infection with non-albicans Candida strains compared to worms that were not exposed to the probiotic yeasts. Furthermore, application of probiotic yeasts postinfection with non-albicans Candida alleviated pathogenic colonization of the nematode gut. The probiotic properties of these novel yeasts are better than or comparable to those of the commercially available probiotic yeast Saccharomyces boulardii, which was used as a reference strain throughout this study. These results indicate that yeasts derived from food sources could serve as an effective alternative to antifungal therapy against emerging pathogenic Candida species.IMPORTANCE Non-albicans Candida-associated infections have emerged as a major risk factor in the hospitalized and immunecompromised patients. Besides, antifungal-associated complications occur more frequently with these non-albicans Candida species than with C. albicans Therefore, as an alternative approach to combat these widespread non-albicans Candida-associated infections, here we showed the probiotic effect of two yeasts, Saccharomyces cerevisiae (strain KTP) and Issatchenkia occidentalis (ApC), in preventing adhesion and biofilm formation of five non-albicans Candida strains, Candida tropicalis, Candida krusei, Candida glabrata, Candida parapsilosis, and Candida auris The result would influence the current trend of the conversion of conventional antimicrobial therapy into beneficial probiotic microbe-associated antimicrobial treatment.

Saccharomyces cerevisiae CNCM I-3856 as a New Therapeutic Agent Against Oropharyngeal Candidiasis

Oropharyngeal candidiasis is a common opportunistic mucosal infection of the oral cavity, mainly caused by an overgrowth of Candida albicans. This infection can inhibit nutritional intakes and strongly affect quality of life. To date, standard therapeutic strategies involving the administration of antifungal drugs can bring several side effects, not least the emergence of drug-resistant strains. The purpose of this study is to investigate the effectiveness of Saccharomyces cerevisiae CNCM I-3856 (live or inactivated cells) against oropharyngeal candidiasis. Our results show that administration of S. cerevisiae CNCM I-3856 (live or inactivated cells) in the oral cavity of C57BL/6J mice resulted in a protective effect against oropharyngeal candidiasis. The strongest effect was obtained with live S. cerevisiae CNCM I-3856. This was related to: (1) a decrease in C. albicans load in the oral cavity, esophagus, stomach, and duodenum; (2) an early resolution of inflammatory process in the tongue; (3) a marked reduction in C. albicans virulence factors; and (4) a consistent increase in neutrophil antimicrobial capacity. These findings suggest that S. cerevisiae products are potentially beneficial in the treatment of oropharyngeal candidiasis.

Interplay Between the Host, the Human Microbiome, and Drug Metabolism

The human microbiome is composed of four major areas including intestinal, skin, vaginal, and oral microbiomes, with each area containing unique species and unique functionalities. The human microbiome may be modulated with prebiotics, probiotics, and postbiotics to potentially aid in the treatment of diseases like irritable bowel syndrome, bacterial vaginosis, atopic dermatitis, gingivitis, obesity, or cancer. There is also potential for many of the inhabitants of the human microbiome to directly modulate host gene expression and modulate host detoxifying enzyme activity like cytochrome P450s (CYPs), dehydrogenases, and carboxylesterases. Therefore, the microbiome may be important to consider during drug discovery, risk assessment, and dosing regimens for various diseases given that the human microbiome has been shown to impact host detoxification processes.

Antagonistic effect of Saccharomyces cerevisiae KTP and Issatchenkia occidentalis ApC on hyphal development and adhesion of Candida albicans

The morphological transition from yeast to a hyphal form, as well as the adhesion capability to the gastrointestinal tract, are implicated virulent determinant in Candida albicans and could be potential targets for prevention of the opportunistic pathogen. Based on this rationale, two yeast strains Saccharomyces cerevisiae KTP and Issatchenkia occidentalis ApC along with reference strain Saccharomyces boulardii NCDC 363 were screened for the probiotic potential. Characters like pH, temperature, bile, simulated gastrointestinal juice tolerance tests, and Caco-2 cell line adhesion assay were determined in the present study. Further, the evaluation of its impact on C. albicans morphological transition and adhesion was assessed using microtitre germ tube test. In terms of probiotic characteristics, both the strains were tolerant to pH 2.5 and the presence of bile (0.3 to 0.6%) with an optimum growth temperature of 37°C. The strain KTP was also resistant to simulated gastric and intestinal juices as compared to control (13% and 41%, respectively) and NCDC 363 (55% and 35%, respectively). In contrast, both the yeasts had reduced adhesiveness to Caco-2 monolayer. Candida virulence in in vitro systems indicated that treatment of live probiotic yeast cells (108 ml) effectively reduced the filamentation and adhesion of C. albicans. The S. cerevisiae KTP had a profound effect on the hyphal development and adhesion when compared to the ApC and NCDC 363. The strain significantly reduced (P < .05) the hyphal growth in co-cultivated (93% and 94%, respectively) and pre-existing hyphae (54% and 68%) of strains C. albicans 183 and 1151. Isolates KTP and ApC also reduced the adhesion (≈ 22% and 41%, respectively) and transition of blastoconidia at two hours of incubation in abiotic surface. This study provides knowledge on the effect of potential probiotic yeasts such as Saccharomyces and non- Saccharomyces strains against virulence characteristic of Candida albicans.