Lactobacillus rhamnosus colonisation antagonizes Candida albicans by forcing metabolic adaptations that compromise pathogenicity

LC-MS/MS-based metabolomic of pink Auricularia cornea grown on Lycium barbarum sawdust substrate

Driven by the need for sustainable agriculture, using Lycium barbarum (goji) sawdust as a substrate for mushroom cultivation increases productivity while reducing environmental impact. This study evaluates the effects of different proportions of goji sawdust on the growth, yield, and metabolic profiles of pink A. cornea. Six substrate formulations were tested, with 16 % goji sawdust supporting optimal yield and quality. LC-MS/MS-based metabolomics identified 1335 metabolites, mainly organic acids and derivatives, lipids and lipid-like molecules, organoheterocyclic compounds, and benzenoids. Biomarker analysis revealed twenty to thirty-five metabolites associated with substrate variations. KEGG enrichment highlighted key metabolic pathways, including ABC transporters, amino acid biosynthesis, D-amino acid metabolism, and aminoacyl-tRNA biosynthesis, contributing to substrate adaptation. While this study offers insights into the metabolic responses of pink A. cornea to goji sawdust, future research should incorporate absolute biomarkers quantification to further validate these results and optimize substrate compositions.

Atomic Insights Into Self-Assembly of Zingibroside R1 and its Therapeutic Action Against Fungal Diseases

Natural products are a crucial resource for drug discovery, but poor understanding of the molecular-scale mechanisms of their self-assembly into soluble, bioavailable hydrogels limits their applications and therapeutic potential. It is demonstrated that Zingibroside R1 (ZR1), derived from Panax notoginseng, undergoes spontaneous self-assemble into a hydrogel comprising helical nanofibrils with potent antifungal activity lacking in its monomeric state. Cryogenic electron microscopy (cryo-EM) revealed an intricate hydrogen-bonding network that facilitates ZR1 nanofibril formation, characterized by a hydrophobic core and hydrophilic exterior architecture, which underpin its binding activity with cell wall in the vulvovaginal candidiasis (VVC) pathogen, C. albicans. The hydrogen-bonding interface between ZR1 gel and glucan compromises membrane integrity, inhibiting C. albicans proliferation in vitro and in VVC model mice in vivo. ZR1 gel could also deliver probiotic Lactobacillus, synergistically inhibiting VVC and restoring the vaginal microenvironment. This study advances the mechanistic understanding of ZR1's structure-function relationships, offering valuable insights into the rational design and therapeutic optimization of natural product-based hydrogels.

Commensalism and pathogenesis of Candida albicans at the mucosal interface

Fungi are important and often underestimated human pathogens. Infections with fungi mostly originate from the environment, from soil or airborne spores. By contrast, Candida albicans, one of the most common and clinically important fungal pathogens, permanently exists in the vast majority of healthy individuals as a member of the human mucosal microbiota. Only under certain circumstances will these commensals cause infections. However, although the pathogenic behaviour and disease manifestation of C. albicans have been at the centre of research for many years, its asymptomatic colonization of mucosal surfaces remains surprisingly understudied. In this Review, we discuss the interplay of the fungus, the host and the microbiome on the dualism of commensal and pathogenic life of C. albicans, and how commensal growth is controlled and permitted. We explore hypotheses that could explain how the mucosal environment shapes C. albicans adaptations to its commensal lifestyle, while still maintaining or even increasing its pathogenic potential.

Genome-scale metabolic modeling reveals specific vaginal Lactobacillus strains and their metabolites as key inhibitors of Candida albicans

As the predominant constituents of the vaginal microbiome in healthy women, Lactobacillus species are considered essential in maintaining a homeostatic vaginal microbiome. Specific Lactobacillus species can produce beneficial metabolites to support their persistence within the host environment and inhibit Candida albicans colonization. Due to the extensive diversity of Lactobacillus species and their metabolites, comprehensively investigating all possible interactions remains challenging. This study employed an integrative approach combining genome-scale metabolic modeling, metagenomic sequencing, and in vitro validation to explore Lactobacillus and C. albicans interactions. Pairwise simulations of 159 Lactobacillus strains with C. albicans revealed that most strains exhibit inhibitory effects, altering fungal amino acid and carbohydrate metabolism. Key inhibitory metabolites identified included formate, L-lactate, and L-malate. Metagenomic analysis of vaginal swabs from 20 vulvovaginal candidiasis (VVC) patients and 20 healthy women showed a correlation between Lactobacillus species abundance and reduced C. albicans colonization. In vitro experiments confirmed the inhibitory effects of these metabolites and the selected Lactobacillus strains on C. albicans growth, thereby validating our computational predictions. These findings provide insights into the metabolic interactions within the vaginal microbiome and pave the way for targeted microbial or metabolite-based therapeutic strategies to manage VVC.IMPORTANCEVulvovaginal candidiasis is a prevalent fungal infection with significant implications for women's health, caused primarily by Candida albicans. Although the protective role of a Lactobacillus-dominated vaginal microbiome is well established, the metabolic mechanisms underlying the interactions between Lactobacillus species and C. albicans remain inadequately understood. Specifically, the Lactobacillus species that effectively inhibit C. albicans and the metabolic pathways involved warrant further investigation. This study offers novel insights into the metabolic mechanisms underlying Lactobacillus antagonism against C. albicans. By identifying critical metabolic pathways and inhibitory metabolites, this study enhances our understanding of vaginal microbiome dynamics and host-microbe interactions. The findings suggest that key Lactobacillus strains and their metabolites could significantly reduce harmful levels of C. albicans, paving the way for future therapeutic strategies that leverage these microbial characteristics to promote vaginal health.

The Role of Intestinal Fungi in the Pathogenesis and Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease closely associated with dysbiosis of the gut microbiome, encompassing not only bacterial communities but also fungal populations. Despite the growing recognition of the gut microbiome's role in UC pathogenesis, the contribution of intestinal fungi has only recently garnered significant attention. In this review, we comprehensively examine the characteristics of intestinal fungi in both healthy individuals and UC patients, elucidating their role in disease pathogenesis and their interactions with bacterial communities. Additionally, we explore the impact of intestinal fungi on disease severity and therapeutic responses in UC. Furthermore, we evaluate the therapeutic potential of antifungal agents, probiotics, and fecal microbiota transplantation (FMT) in UC management, emphasizing the critical role of fungi in these treatment modalities. Future research should prioritize elucidating the multifunctional roles of fungi in UC pathogenesis and their implications for treatment strategies. Moreover, the identification of fungal biomarkers associated with FMT efficacy could pave the way for precision medicine approaches in FMT, offering novel insights into personalized therapeutic interventions for UC.

Image-based quantification of Candida albicans filamentation and hyphal length using the open-source visual programming language JIPipe

The formation of hyphae is one of the most crucial virulence traits the human pathogenic fungus Candida albicans possesses. The assessment of hyphal length in response to various stimuli, such as exposure to human serum, provides valuable insights into the adaptation strategies of C. albicans to the host environment. Despite the increasing high-throughput capacity live-cell imaging and data generation, the accurate analysis of hyphal growth has remained a laborious, error-prone, and subjective manual process. We developed an analysis pipeline utilizing the open-source visual programming language Java Image Processing Pipeline (JIPipe) to overcome the limitations associated with manual analysis of hyphal growth. By comparing our automated approach with manual analysis, we refined the strategies to achieve accurate differentiation between yeast cells and hyphae. The automated method enables length measurements of individual hyphae, facilitating a time-efficient, high-throughput, and user-friendly analysis. By utilizing this JIPipe analysis approach, we obtained insights into the filamentation behavior of two C. albicans strains when exposed to human serum albumin (HSA), the most abundant protein in human serum. Our findings indicate that despite the known role of HSA in stimulating fungal growth, it reduces filamentous growth. The implementation of our automated JIPipe analysis approach for hyphal growth represents a long-awaited and time-efficient solution to meet the demand of high-throughput data generation. This tool can benefit different research areas investigating the virulence aspects of C. albicans.

Efficacy and compatibility mechanism of bear bile powder in Shexiang Tongxin dropping pills for acute myocardial infarction treatment

BACKGROUND

Bear bile powder (BBP), a unique animal-derived medicine with anti-inflammatory and antioxidant effects, is used in Shexiang Tongxin dropping pills (STDP), which is applied to treat cardiovascular diseases, including acute myocardial infarction (AMI). The efficacy and compatibility mechanisms of action of BBP in STDP against cardiovascular diseases remain unclear. This study aimed to investigate the compatibility effects of BBP in STDP in rats with AMI.

METHODS

We investigated the compatibility effects of BBP in STDP in rats with AMI. Non-targeted metabonomics, 16S rRNA analysis, RNA sequencing, and network pharmacology were performed to explore the underlying mechanisms.

RESULTS

The combination of BBP and CF (STDP without BBP) significantly reduced AMI-induced infarction size, pathological alterations of cardiac tissues, and serum lactate dehydrogenase and creatine kinase levels in rats, compared with CF or BBP treatment alone. Gut microbiota and metabonomics results revealed that the combination treatment could upregulate the relative abundance of Lactobacillus and downregulate that of Helicobacter, Bilophila, and Butyricimonas, thereby rebalancing the gut microbiota dysbiosis induced by AMI. Consequently, the intestinal metabolite levels of oleoylcholine, glutamylalanine, isokobusone, and hemorphin-4 were altered. However, treatment with CF or BBP alone has a weaker effect on these bacteria. Additionally, the combination treatment induced a 62.34% gene reversion rate compared with 55.56% for BBP and 30.20% for CF treatment alone. Modulation of endothelin 1 and growth factor receptor-bound protein 2 was identified as a key synergistic mechanism underlying the anti-AMI effects of BBP in STDP.

CONCLUSION

This research provides a scientific explanation of the compatibility of BBP in STDP. Our findings suggested that combination treatment with CF and BBP synergistically attenuates AMI by altering gene expression, gut microbiota, and intestinal metabolite profiles.

Shining a light on Candida-induced epithelial damage with a luciferase reporter

Host cell damage is a key parameter for research in infection biology, drug testing, and substance safety screening. In this study, we introduce a luciferase reporter system as a new and reliable assay to measure cell damage and validate it with the pathogenic yeast, Candida albicans, as a test case. We transduced human epithelial cell lines with a lentiviral vector to stably express an optimized luciferase enzyme, Nanoluc. Upon cell damage, the release of cytoplasmic luciferase into the extracellular space can be easily detected by a luminometer. We used the luciferase reporter system to investigate the damage caused by C. albicans to different newly generated epithelial reporter cell lines. We found that fungus-induced cell damage, as determined by established methods, correlated tightly with the release of the luciferase. The new luciferase reporter system is a simple, sensitive, robust, and inexpensive method for measuring host cell damage and has a sensitivity comparable to the standard assay, release of lactate dehydrogenase. It is suitable for high-throughput studies of pathogenesis mechanisms of any microbe, for antimicrobial drug screening, and many other applications.IMPORTANCEWe present a quick, easy, inexpensive, and reliable assay to measure damage to mammalian cells. To this end, we created reporter cell lines which artificially express luciferase, an enzyme that can be easily detected in the supernatant when these cells are damaged. We used infections with the well-investigated fungal pathogen of humans, Candida albicans, as a test case of our system. Using our reporter, we were able to recapitulate the known effects of strain variability, gene deletions, and antifungal treatments on host cell damage. This easily adaptable reporter system can be used to screen for damage in infection models with different microbial species, assay cell-damaging potential of substances, discover new non-toxic antibiotics, and many other damage-based applications.

Limosilactobacillus fermentum KBL674 Alleviates Vaginal Candidiasis

Candida albicans (C. albicans) is the primary etiologic agent of vaginal candidiasis. Lactobacillus species are predominant in the vaginal microbiome; they inhibit the development of vaginal candidiasis by producing antimicrobial agents, such as lactic acid and hydrogen peroxide. In this study, we investigated the effects of Limosilactobacillus fermentum (L. fermentum) KBL674 in a mouse model of vaginal candidiasis. L. fermentum KBL674 inhibited C. albicans hyphal growth. Moreover, oral administration of L. fermentum KBL674 significantly suppressed vaginal C. albicans infection and associated symptoms, including tissue thickness and immune cell infiltration. A substantial quantity of L. fermentum KBL674 was excreted by the mice within 6 h after oral administration, indicating that most L. fermentum KBL674 did not settle within the gastrointestinal tract. L. fermentum KBL674 modulated gut microbiome diversity, increasing abundances of the genera Akkermansia, Eubacterium, and Faecalibaculum and family Muribaculaceae. Abundances of these bacteria showed negative correlations with the vaginal C. albicans burden in the mouse model, suggesting links between the gut microbiome composition and the vaginal C. albicans burden. Therefore, L. fermentum KBL674 can reduce the vaginal C. albicans burden via direct or indirect inhibition and modulation of the gut microbiome composition preventively.

Integrated multi-omics identifies pathways governing interspecies interaction between A. fumigatus and K. pneumoniae

Polymicrobial co- and superinfections involving bacterial and fungal pathogens pose serious challenges for diagnosis and therapy, and are associated with elevated morbidity and mortality. However, the metabolic dynamics of bacterial-fungal interactions (BFI) and the resulting impact on disease outcome remain largely unknown. The fungus Aspergillus fumigatus and the bacterium Klebsiella pneumoniae are clinically important pathogens sharing common niches in the human body, especially in the lower respiratory tract. We have exploited an integrated multi-omics approach to unravel the complex and multifaceted processes implicated in the interspecies communication involving these pathogens in mixed biofilms. In this setting, A. fumigatus responds to the bacterial challenge by rewiring its metabolism, attenuating the translational machineries, and by connecting secondary with primary metabolism, while K. pneumoniae maintains its central metabolism and translation activity. The flexibility in the metabolism of A. fumigatus and the ability to quickly adapt to the changing microenvironment mediated by the bacteria highlight new possibilities for studying the impact of cross-communication between competing interaction partners. The data underscore the complexity governing the dynamics underlying BFI, such as pronounced metabolic changes mounted in A. fumigatus interacting with K. pneumoniae. Our findings identify candidate biomarkers potentially exploitable for improved clinical management of BFI.

The pathobiology of human fungal infections

Human fungal infections are a historically neglected area of disease research, yet they cause more than 1.5 million deaths every year. Our understanding of the pathophysiology of these infections has increased considerably over the past decade, through major insights into both the host and pathogen factors that contribute to the phenotype and severity of these diseases. Recent studies are revealing multiple mechanisms by which fungi modify and manipulate the host, escape immune surveillance and generate complex comorbidities. Although the emergence of fungal strains that are less susceptible to antifungal drugs or that rapidly evolve drug resistance is posing new threats, greater understanding of immune mechanisms and host susceptibility factors is beginning to offer novel immunotherapeutic options for the future. In this Review, we provide a broad and comprehensive overview of the pathobiology of human fungal infections, focusing specifically on pathogens that can cause invasive life-threatening infections, highlighting recent discoveries from the pathogen, host and clinical perspectives. We conclude by discussing key future challenges including antifungal drug resistance, the emergence of new pathogens and new developments in modern medicine that are promoting susceptibility to infection.

Bacteria-derived short-chain fatty acids as potential regulators of fungal commensalism and pathogenesis

The human gastrointestinal microbiome encompasses bacteria, fungi, and viruses forming complex bionetworks which, for organismal health, must be in a state of homeostasis. An important homeostatic mechanism derives from microbial competition, which maintains the relative abundance of microbial species in a healthy balance. Microbes compete for nutrients and secrete metabolites that inhibit other microbes. Short-chain fatty acids (SCFAs) are one such class of metabolites made by gut bacteria to very high levels. SCFAs are metabolised by microbes and host cells and have multiple roles in regulating cell physiology. Here, we review the mechanisms by which SCFAs regulate the fungal gut commensal Candida albicans. We discuss SCFA's ability to inhibit fungal growth, limit invasive behaviours and modulate cell surface antigens recognised by immune cells. We review the mechanisms underlying these roles: regulation of gene expression, metabolism, signalling and SCFA-driven post-translational protein modifications by acylation, which contribute to changes in acylome dynamics of C. albicans with potentially large consequences for cell physiology. Given that the gut mycobiome is a reservoir for systemic disease and has also been implicated in inflammatory bowel disease, understanding the mechanisms by which bacterial metabolites, such as SCFAs, control the mycobiome might provide therapeutic avenues.

Lactobacillus johnsonii is a dominant Lactobacillus in the murine oral mucosa and has chitinase activity that compromises fungal cell wall integrity

The oral microbiome is a critical determinant of health and disease, as interactions between oral microorganisms can influence their physiology and the development or severity of oral infections. Lactobacilli have a widely recognized antagonistic relationship with Candida albicans and may exhibit probiotic properties that limit oral fungal infection. We previously reported that Lactobacillus johnsonii strain MT4, an oral strain isolated from C57BL/6 mice, can induce global changes in the murine oral microbiome and has anti-Candida activity in vitro. To build on this information, we analyzed its abundance on the mouse oral mucosa, tested its impact on the severity and progression of oropharyngeal candidiasis (OPC) in a mouse model, and further explored the mechanism of antifungal activity in vitro. Our findings reveal that L. johnsonii MT4 is a dominant cultivable Lactobacillus in the oral mucosa of C57BL/6 mice. Strain MT4 has chitinase activity against C. albicans, which damages the cell wall and compromises fungal metabolic activity. Oral inoculation with strain MT4 causes a reduction in the Candida-induced rise in the abundance of oral enterococci and oral mucosal damage. This research underscores the potential of L. johnsonii strain MT4 as a novel probiotic agent in the prevention or management of OPC, and it contributes to a better understanding of the role of oral bacterial microbiota role in the pathogenesis of fungal infections.

IMPORTANCE

The interactions between the opportunistic pathogen Candida albicans and resident oral bacteria are particularly crucial in maintaining oral health. Emerging antifungal drug-resistant strains, slow-paced drug discovery, and the risk of side effects can compromise the effectiveness of current treatments available for oropharyngeal candidiasis. This study advances the search for alternative microbiome-targeted therapies in oral fungal infections. We report that Lactobacillus johnsonii strain MT4 prevents the Candida-induced bloom of dysbiotic oral enterococci and reduces oral mucosal lesions in an oropharyngeal candidiasis murine model. We also show that this strain directly compromises the cell wall and reduces fungal metabolic activity, partly due to its chitinase activity.

Intestinal fungal-host interactions in promoting and maintaining health

The resident microbiota are a key component of a healthy organism. The vast majority of microbiome studies have focused on bacterial members, which constitute a significant portion of resident microbial biomass. Recent studies have demonstrated how the fungal component of the microbiota, or the mycobiome, influences mammalian biology despite its low abundance compared to other microbes. Fungi are known for their pathogenic potential, yet fungi are also prominent colonizers in healthy states, highlighting their duality. We summarize the characteristics that define the gut mycobiome across life, the factors that can impact its composition, and studies that identify mechanisms of how fungi confer health benefits. The goal of this review is to synthesize our knowledge regarding the composition and function of a healthy mycobiome with a view to inspiring future therapeutic advances.

Host-microbe interaction paradigms in acute and recurrent vulvovaginal candidiasis

Candida spp. are members of the human mucosal microbiota that can cause opportunistic diseases ranging from superficial infections to life-threatening invasive candidiasis. In humans, the most common infection caused by Candida spp. is vulvovaginal candidiasis (VVC), which affects >70% of women at least once in their lifetime. Of those women, ∼5%-10% develop recurrent VVC (RVVC). In this review, we summarize our current understanding of the host and fungal factors that contribute to susceptibility to VVC and RVVC. We synthesize key findings that support the notion that disease symptoms are driven by neutrophil-associated dysfunction and immunopathology and describe how antifungal immune mechanisms in the vagina are distinct from other mucosal barrier sites. Finally, we highlight key, unanswered research areas within the field that can help us better understand the immunopathogenesis of this infection and facilitate the development of novel preventive, therapeutic, and/or vaccination strategies to combat these common, poorly understood diseases.

Vaginal fungi are associated with treatment-induced shifts in the vaginal microbiota and with a distinct genital immune profile

Vaginal colonization by fungi may elicit genital inflammation and enhance the risk of adverse reproductive health outcomes, such as HIV acquisition. Cross-sectional studies have linked fungi with an absence of bacterial vaginosis (BV), but it is unclear whether shifts in vaginal bacteria alter the abundance of vaginal fungi. Vaginal swabs collected following topical metronidazole treatment for BV during the phase 2b, placebo-controlled trial of LACTIN-V, a Lactobacillus crispatus-based live biotherapeutic, were assayed with semi-quantitative PCR for the relative quantitation of fungi and key bacterial species and multiplex immunoassay for immune factors. Vaginal fungi increased immediately following metronidazole treatment for BV (adjusted P = 0.0006), with most of this increase attributable to Candida albicans. Vaginal fungi were independently linked to elevated levels of the proinflammatory cytokine interleukin (IL) 17A, although this association did not remain significant after correcting for multiple comparisons. Fungal relative abundance by semi-quantitative PCR returned to baseline levels within 1 month of metronidazole treatment and was not affected by LACTIN-V or placebo administration. Fungal abundance was positively associated with Lactobacillus species, negatively associated with BV-associated bacteria, and positively associated with a variety of proinflammatory cytokines and chemokines, including IL-17A, during and after study product administration. Antibiotic treatment for BV resulted in a transient expanded abundance of vaginal fungi in a subset of women which was unaffected by subsequent administration of LACTIN-V. Vaginal fungi were positively associated with Lactobacillus species and IL-17A and negatively associated with BV-associated bacteria; these associations were most pronounced in the longer-term outcomes.IMPORTANCEVaginal colonization by fungi can enhance the risk of adverse reproductive health outcomes and HIV acquisition, potentially by eliciting genital mucosal inflammation. We show that standard antibiotic treatment for bacterial vaginosis (BV) results in a transient increase in the absolute abundance of vaginal fungi, most of which was identified as Candida albicans. Vaginal fungi were positively associated with proinflammatory immune factors and negatively associated with BV-associated bacteria. These findings improve our understanding of how shifts in the bacterial composition of the vaginal microbiota may enhance proliferation by proinflammatory vaginal fungi, which may have important implications for risk of adverse reproductive health outcomes among women.

The gut-lung axis: the impact of the gut mycobiome on pulmonary diseases and infections

The gastrointestinal tract contains a diverse microbiome consisting of bacteria, fungi, viruses and archaea. Although these microbes usually reside as commensal organisms, it is now well established that higher abundance of specific bacterial or fungal species, or loss of diversity in the microbiome can significantly affect development, progression and outcomes in disease. Studies have mainly focused on the effects of bacteria, however, the impact of other microbes, such as fungi, has received increased attention in the last few years. Fungi only represent around 0.1% of the total gut microbial population. However, key fungal taxa such as Candida, Aspergillus and Wallemia have been shown to significantly impact health and disease. The composition of the gut mycobiome has been shown to affect immunity at distal sites, such as the heart, lung, brain, pancreas, and liver. In the case of the lung this phenomenon is referred to as the 'gut-lung axis'. Recent studies have begun to explore and unveil the relationship between gut fungi and lung immunity in diseases such as asthma and lung cancer, and lung infections caused by viruses, bacteria and fungi. In this review we will summarize the current, rapidly growing, literature describing the impact of the gut mycobiome on respiratory disease and infection.

Exploring the role of candidalysin in the pathogenicity of Candida albicans by gene set enrichment analysis and evolutionary dynamics

AIMS

To explore the pathogenic mechanisms of Candida albicans (C. albicans), focusing on its impact on human health, particularly through invasive infections in the gastrointestinal and respiratory tracts.

METHODS

In this study, we evaluated the demographic and clinical profiles of 7 pneumonia patients. Meanwhile, we used Gene Set Enrichment Analysis (GSEA) and Evolutionary Dynamics method to analyze the role of candidalysin in C. albicans pathogenicity.

RESULTS

By analyzing genomic data and conducting biomedical text mining, we identified novel mutation sites in the candidalysin coding gene ECE1-III, shedding light into the genetic diversity within C. albicans strains and their potential implications for antifungal resistance. Our results revealed significant associations between C. albicans and respiratory as well as gastrointestinal diseases, emphasizing the fungus's role in the pathogenesis of these diseases. Additionally, we identified a new mutation site in the C. albicans strain YF2-5, isolated from patients with pneumonia. This mutation may be associated with its heightened pathogenicity.

CONCLUSION

Our research advances the understanding of C. albicans pathogenicity and opens new avenues for developing targeted antifungal therapies. By focusing on the molecular basis of fungal virulence, we aim to contribute to the development of more effective treatment strategies, addressing the challenge of multidrug resistance in invasive fungal infections.

Harnessing the Power of a Novel Triple Chelate Complex in Fermented Probiotic Dairy Products: A Promising Solution for Combating Iron Deficiency Anemia

This study discovered and examined novel triple chelate complexes involving iron, ascorbic acid, and essential amino acids (AsA-Fe-AmA triple chelate complexes) for the first time. The mechanism of complex formation was studied using FTIR spectroscopy and quantum chemical modeling. The produced complexes were shown to be suitable for fortifying food items with a pH of 3-7 that have not been exposed to heat treatment at temperatures over 75 °C for more than 15 min. Thus, it can be said that the concentration for milk fortification should be 0.005 mol/L or less. In vivo experiments in rats models revealed that the synthesized complexes increased serum iron levels after a single application to reference values within 24 h of oral administration. The iron level increased by 14.0 mmol/L at 2 mL dose of the complex. This fact makes it possible to consider the use of developed complexes and developed fermented dairy products for the prevention of iron deficiency and iron deficiency anemia. Research on the effect of discovered compounds on the physicochemical and organoleptic qualities of milk was conducted. Furthermore, iron ascorbate threoninate, iron ascorbate methioninate, iron ascorbate lysinate, and iron ascorbate tryptophanate all had a beneficial effect on Lacticaseibacillus rhamnosus at concentrations as low as 0.0005 mol/L, which is significant for milk fermentation. A study of fermented milk products revealed that the most effective AsA-Fe-AmA triple chelate complex is iron ascorbate lysinate, which might be further investigated as a viable molecule for dietary fortification in iron deficiency anemia. It was found that fortified fermented milk products had a titratable acidity of 67 ± 1°T, pH of 4.38 ± 0.05, and a viscosity of 2018 ± 142 Pa·s.

The impact of the host microbiota on Candida albicans infection

The human microbiota is a complex microbial ecosystem populated by bacteria, fungi, viruses, protists, and archaea. The coexistence of fungi alongside with many billions of bacteria, especially in the gut, involves complex interactions, ranging from antagonistic to beneficial, between the members of these two kingdoms. Bacteria can impact fungi through various means, such as physical interactions, secretion of metabolites, or alteration of the host immune response, thereby affecting fungal growth and virulence. This review summarizes recent progress in this field, delving into the latest understandings of bacterial-fungal-immune interactions and innovative therapeutic approaches addressing the challenges of treating fungal infections associated with microbiota imbalances.

The immune and microbial homeostasis determines the Candida-mast cells cross-talk in celiac disease

Celiac disease (CD) is an autoimmune enteropathy resulting from an interaction between diet, genome, and immunity. Although many patients respond to a gluten-free diet, in a substantive number of individuals, the intestinal injury persists. Thus, other factors might amplify the ongoing inflammation. Candida albicans is a commensal fungus that is well adapted to the intestinal life. However, specific conditions increase Candida pathogenicity. The hypothesis that Candida may be a trigger in CD has been proposed after the observation of similarity between a fungal wall component and two CD-related gliadin T-cell epitopes. However, despite being implicated in intestinal disorders, Candida may also protect against immune pathologies highlighting a more intriguing role in the gut. Herein, we postulated that a state of chronic inflammation associated with microbial dysbiosis and leaky gut are favorable conditions that promote C. albicans pathogenicity eventually contributing to CD pathology via a mast cells (MC)-IL-9 axis. However, the restoration of immune and microbial homeostasis promotes a beneficial C. albicans-MC cross-talk favoring the attenuation of CD pathology to alleviate CD pathology and symptoms.

Candida albicans and Candida glabrata: global priority pathogens

SUMMARYA significant increase in the incidence of Candida-mediated infections has been observed in the last decade, mainly due to rising numbers of susceptible individuals. Recently, the World Health Organization published its first fungal pathogen priority list, with Candida species listed in medium, high, and critical priority categories. This review is a synthesis of information and recent advances in our understanding of two of these species-Candida albicans and Candida glabrata. Of these, C. albicans is the most common cause of candidemia around the world and is categorized as a critical priority pathogen. C. glabrata is considered a high-priority pathogen and has become an increasingly important cause of candidemia in recent years. It is now the second most common causative agent of candidemia in many geographical regions. Despite their differences and phylogenetic divergence, they are successful as pathogens and commensals of humans. Both species can cause a broad variety of infections, ranging from superficial to potentially lethal systemic infections. While they share similarities in certain infection strategies, including tissue adhesion and invasion, they differ significantly in key aspects of their biology, interaction with immune cells, host damage strategies, and metabolic adaptations. Here we provide insights on key aspects of their biology, epidemiology, commensal and pathogenic lifestyles, interactions with the immune system, and antifungal resistance.

Candida albicans accelerates atherosclerosis by activating intestinal hypoxia-inducible factor2α signaling

The gut microbiota is closely linked to atherosclerosis. However, the role of intestinal fungi, essential members of the complex microbial community, in atherosclerosis is poorly understood. Herein, we show that gut fungi dysbiosis is implicated in patients with dyslipidemia, characterized by higher levels of Candida albicans (C. albicans), which are positively correlated with plasma total cholesterol and low-density lipoprotein-cholesterol (LDL-C) levels. Furthermore, C. albicans colonization aggravates atherosclerosis progression in a mouse model of the disease. Through gain- and loss-of-function studies, we show that an intestinal hypoxia-inducible factor 2α (HIF-2α)-ceramide pathway mediates the effect of C. albicans. Mechanistically, formyl-methionine, a metabolite of C. albicans, activates intestinal HIF-2α signaling, which drives increased ceramide synthesis to accelerate atherosclerosis. Administration of the HIF-2α selective antagonist PT2385 alleviates atherosclerosis in mice by reducing ceramide levels. Our findings identify a role for intestinal fungi in atherosclerosis progression and highlight the intestinal HIF-2α-ceramide pathway as a target for atherosclerosis treatment.

Modeling of intravenous caspofungin administration using an intestine-on-chip reveals altered Candida albicans microcolonies and pathogenicity

Candida albicans is a commensal yeast of the human intestinal microbiota that, under predisposing conditions, can become pathogenic and cause life-threatening systemic infections (candidiasis). Fungal-host interactions during candidiasis are commonly studied using conventional 2D in vitro models, which have provided critical insights into the pathogenicity. However, microphysiological models with a higher biological complexity may be more suitable to mimic in vivo-like infection processes and antifungal drug efficacy. Therefore, a 3D intestine-on-chip model was used to investigate fungal-host interactions during the onset of invasive candidiasis and evaluate antifungal treatment under clinically relevant conditions. By combining microbiological and image-based analyses we quantified infection processes such as invasiveness and fungal translocation across the epithelial barrier. Additionally, we obtained novel insights into fungal microcolony morphology and association with the tissue. Our results demonstrate that C. albicans microcolonies induce injury to the epithelial tissue by disrupting apical cell-cell contacts and causing inflammation. Caspofungin treatment effectively reduced the fungal biomass and induced substantial alterations in microcolony morphology during infection with a wild-type strain. However, caspofungin showed limited effects after infection with an echinocandin-resistant clinical isolate. Collectively, this organ-on-chip model can be leveraged for in-depth characterization of pathogen-host interactions and alterations due to antimicrobial treatment.

Competitive fungal commensalism mitigates candidiasis pathology

The mycobiota are a critical part of the gut microbiome, but host-fungal interactions and specific functional contributions of commensal fungi to host fitness remain incompletely understood. Here, we report the identification of a new fungal commensal, Kazachstania heterogenica var. weizmannii, isolated from murine intestines. K. weizmannii exposure prevented Candida albicans colonization and significantly reduced the commensal C. albicans burden in colonized animals. Following immunosuppression of C. albicans colonized mice, competitive fungal commensalism thereby mitigated fatal candidiasis. Metagenome analysis revealed K. heterogenica or K. weizmannii presence among human commensals. Our results reveal competitive fungal commensalism within the intestinal microbiota, independent of bacteria and immune responses, that could bear potential therapeutic value for the management of C. albicans-mediated diseases.

A molecular view on the interference established between vaginal Lactobacilli and pathogenic Candida species: Challenges and opportunities for the development of new therapies

Vaginal infectious diseases caused by viruses and bacteria have been linked to the occurrence of dysbiosis, that is, a reduction in the abundance of the normally dominating vaginal Lactobacillus species. Mucosal infections in the vagina and/or vulva caused by Candida species, usually known as vulvovaginal candidiasis (or VVC), are among the leading causes of diseases in the vaginal tract. The existence of a clear link between the occurrence of dysbiosis and the development of VVC is still unclear, although multiple observations point in that direction. Based on the idea that vaginal health is linked to a microbiota dominated by lactobacilli, several probiotics have been used in management of VVC, either alone or in combination with antifungals, having obtained different degrees of success. In most cases, the undertaken trials resorted to lactobacilli species other than those indigenous to the vaginal tract, although in vitro these vaginal species were shown to reduce growth, viability and virulence of Candida. In this paper we overview the role of lactobacilli and Candida in the vaginal micro- and myco-biomes, while discussing the results obtained in what concerns the establishment of interference mechanisms in vivo and the environmental factors that could determine that. We also overview the molecular mechanisms by which lactobacilli species have been shown to inhibit pathophysiology of Candida, including the description of the genes and pathways determining their ability to thrive in the presence of each other. In a time where concerns are increasing with the emergence of antifungal resistance and the slow pace of discovery of new antifungals, a thorough understanding of the molecular mechanisms underneath the anti-Candida effect prompted by vaginal lactobacilli is of utmost importance to assure a knowledge-based design of what can be a new generation of pharmaceuticals, eventually focusing therapeutic targets other than the usual ones.

An Untargeted Metabolomic Analysis of Lacticaseibacillus (L.) rhamnosus, Lactobacillus (L.) acidophilus, Lactiplantibacillus (L.) plantarum and Limosilactobacillus (L.) reuteri Reveals an Upregulated Production of Inosine from L. rhamnosus

Lactic acid bacteria are considered an inexhaustible source of bioactive compounds; indeed, products from their metabolism are known to have immunomodulatory and anti-inflammatory activity. Recently, we demonstrated that Cell-Free Supernatants (CFS) obtained from Lactobacillus (L.) acidophilus, Lactiplantibacillus (L.) plantarum, Lacticaseibacillus (L.) rhamnosus, and Limosilactobacillus (L.) reuteri can impair Candida pathogenic potential in an in vitro model of epithelial vaginal infection. This effect could be ascribed to a direct effect of living lactic acid bacteria on Candida virulence and to the production of metabolites that are able to impair fungal virulence. In the present work, stemming from these data, we deepened our knowledge of CFS from these four lactic acid bacteria by performing a metabolomic analysis to better characterize their composition. By using an untargeted metabolomic approach, we detected consistent differences in the metabolites produced by these four different lactic acid bacteria. Interestingly, L. rhamnosus and L. acidophilus showed the most peculiar metabolic profiles. Specifically, after a hierarchical clustering analysis, L. rhamnosus and L. acidophilus showed specific areas of significantly overexpressed metabolites that strongly differed from the same areas in other lactic acid bacteria. From the overexpressed compounds in these areas, inosine from L. rhamnosus returned with the best identification profile. This molecule has been described as having antioxidant, anti-inflammatory, anti-infective, and neuroprotective properties. The biological significance of its overproduction by L. rhamnosus might be important in its probiotic and/or postbiotic activity.

Elemental sulfur enhances the anti-fungal effect of Lacticaseibacillus rhamnosus Lcr35

Lacticaseibacillus rhamnosus Lcr35 is a well-known bacterial strain whose efficiency in preventing recurrent vulvovaginal candidiasis has been largely demonstrated in clinical trials. The presence of sodium thiosulfate (STS) has been shown to enhance its ability to inhibit the growth of Candida albicans strains. In this study, we confirmed that Lcr35 has a fungicidal effect not only on the planktonic form of C. albicans but also on other life forms such as hypha and biofilm. Transcriptomic analysis showed that the presence of C. albicans induced a metabolic adaptation of Lcr35 potentially associated with a competitive advantage over yeast cells. However, STS alone had no impact on the global gene expression of Lcr35, which is not in favor of the involvement of an enzymatic transformation of STS. Comparative HPLC and gas chromatography-mass spectrometry analysis of the organic phase from cell-free supernatant (CFS) fractions obtained from Lcr35 cultures performed in the presence and absence of STS identified elemental sulfur (S0) in the samples initially containing STS. In addition, the anti-Candida activity of CFS from STS-containing cultures was shown to be pH-dependent and occurred at acidic pH lower than 5. We next investigated the antifungal activity of lactic acid and acetic acid, the two main organic acids produced by lactobacilli. The two molecules affected the viability of C. albicans but only at pH 3.5 and in a dose-dependent manner, an antifungal effect that was enhanced in samples containing STS in which the thiosulfate was decomposed into S0. In conclusion, the use of STS as an excipient in the manufacturing process of Lcr35 exerted a dual action since the production of organic acids by Lcr35 facilitates the decomposition of thiosulfate into S0, thereby enhancing the bacteria's own anti-fungal effect.

Direct ammonia oxidation (Dirammox) is favored over cell growth in Alcaligenes ammonioxydans HO-1 to deal with the toxicity of ammonium

Bacteria capable of direct ammonia oxidation (Dirammox) play important roles in global nitrogen cycling and nutrient removal from wastewater. Dirammox process, NH3  → NH2 OH → N2 , first defined in Alcaligenes ammonioxydans HO-1 and encoded by dnf gene cluster, has been found to widely exist in aquatic environments. However, because of multidrug resistance in Alcaligenes species, the key genes involved in the Dirammox pathway and the interaction between Dirammox process and the physiological state of Alcaligenes species remain unclear. In this work, ammonia removal via the redistribution of nitrogen between Dirammox and microbial growth in A. ammonioxydans HO-1, a model organism of Alcaligenes species, was investigated. The dnfA, dnfB, dnfC, and dnfR genes were found to play important roles in the Dirammox process in A. ammonioxydans HO-1, while dnfH, dnfG, and dnfD were not essential genes. Furthermore, an unexpected redistribution phenomenon for nitrogen between Dirammox and cell growth for ammonia removal in HO-1 was revealed. After the disruption of the Dirammox in HO-1, more consumed NH4 + was recovered as biomass-N via rapid metabolic response and upregulated expression of genes associated with ammonia transport and assimilation, tricarboxylic acid cycle, sulfur metabolism, ribosome synthesis, and other molecular functions. These findings deepen our understanding of the molecular mechanisms for Dirammox process in the genus Alcaligenes and provide useful information about the application of Alcaligenes species for ammonia-rich wastewater treatment.

Candida albicans translocation through the intestinal epithelial barrier is promoted by fungal zinc acquisition and limited by NFκB-mediated barrier protection

The opportunistic fungal pathogen Candida albicans thrives on human mucosal surfaces as a harmless commensal, but frequently causes infections under certain predisposing conditions. Translocation across the intestinal barrier into the bloodstream by intestine-colonizing C. albicans cells serves as the main source of disseminated candidiasis. However, the host and microbial mechanisms behind this process remain unclear. In this study we identified fungal and host factors specifically involved in infection of intestinal epithelial cells (IECs) using dual-RNA sequencing. Our data suggest that host-cell damage mediated by the peptide toxin candidalysin-encoding gene ECE1 facilitates fungal zinc acquisition. This in turn is crucial for the full virulence potential of C. albicans during infection. IECs in turn exhibit a filamentation- and damage-specific response to C. albicans infection, including NFκB, MAPK, and TNF signaling. NFκB activation by IECs limits candidalysin-mediated host-cell damage and mediates maintenance of the intestinal barrier and cell-cell junctions to further restrict fungal translocation. This is the first study to show that candidalysin-mediated damage is necessary for C. albicans nutrient acquisition during infection and to explain how IECs counteract damage and limit fungal translocation via NFκB-mediated maintenance of the intestinal barrier.

Inhibiting pathogenicity of vaginal Candida albicans by lactic acid bacteria and MS analysis of their extracellular compounds

Maintaining healthy vaginal microflora post-puberty is critical. In this study we explore the potential of vaginal lactic acid bacteria (LAB) and their extracellular metabolites against the pathogenicity of Candida albicans. The probiotic culture free supernatant (PCFS) from Lactobacillus crispatus, L. gasseri, and L. vaginalis exhibit an inhibitory effect on budding, hyphae, and biofilm formation of C. albicans. LGPCFS manifested the best potential among the LAB PCFS, inhibiting budding for 24 h and restricting hyphae formation post-stimulation. LGPCFS also pre-eminently inhibited biofilm formation. Furthermore, L. gasseri itself grew under RPMI 1640 stimulation suppressing the biofilm formation of C. albicans. The PCFS from the LAB downregulated the hyphal genes of C. albicans, inhibiting the yeast transformation to fungi. Hyphal cell wall proteins HWP1, ALS3, ECE1, and HYR1 and transcription factors BCR1 and CPH1 were downregulated by the metabolites from LAB. Finally, the extracellular metabolome of the LAB was studied by LC-MS/MS analysis. L.gasseri produced the highest antifungal compounds and antibiotics, supporting its best activity against C. albicans. Vaginal LAB and their extracellular metabolites perpetuate C. albicans at an avirulent state. The metabolites produced by these LAB in vitro have been identified, and can be further exploited as a preventive measure against vaginal candidiasis.

Dysbiotic Vaginal Microbiota Induces Preterm Birth Cascade via Pathogenic Molecules in the Vagina

Dysbiotic vaginal microbiota (DVM) disturb the vaginal environment, including pH, metabolite, protein, and cytokine profiles. This study investigated the impact of DVM on the vaginal environment in 40 Korean pregnant women and identified predictable biomarkers of birth outcomes. Cervicovaginal fluid (CVF) samples were collected in the third trimester using vaginal swabs, examined for pH, and stored at -80 °C for further analysis. The samples were grouped as full-term (FTB, n = 20) and preterm (PTB, n = 20) births. The microbiota was profiled in the V1-V9 regions. The levels of targeted metabolites, TLR-4, and cytokines were determined. The pH of CVF from PTB (>4.5) was significantly higher than that of the CVF from FTB (>3.5) (p < 0.05). Neonatal gestational age at delivery, birth weight, and Apgar score differed significantly between groups. The relative abundances of beneficial Lactobacillus spp., such as Lactobacillus gasseri, Lactobacillus jensenii, and Bifidobacterium, were higher in FTB, whereas those of pathogenic Enterococcus faecalis, Staphylococcus, Prevotella, Ureaplasma parvum, and Corynebacterium spp. were higher in PTB. Acetate, methanol, TLR-4, and TNF-α levels were negatively correlated with gestational age at delivery and birth weight. Moreover, ethanol, methanol, TLR-4, IL-6, IL-1β, and TNF-α levels were positively correlated with succinate, acetate, acetoacetate, formate, and ammonia. Overall, DVM induces preterm birth via pathogenic molecules in the vagina.

The mycobiome as integral part of the gut microbiome: crucial role of symbiotic fungi in health and disease

The gut mycobiome significantly affects host health and immunity. However, most studies have focused on symbiotic bacteria in the gut microbiome, whereas less attention has been given to symbiotic fungi. Although fungi constitute only 0.01%-0.1% of the gut microbiome, their larger size and unique immunoregulatory functions make them significant. Factors like diet, antimicrobials use, and age can disrupt the fungal community, leading to dysbiosis. Fungal-bacterial-host immune interactions are critical in maintaining gut homeostasis, with fungi playing a role in mediating immune responses such as Th17 cell activation. This review highlights methods for studying gut fungi, the composition and influencing factors of the gut mycobiome, and its potential in therapeutic interventions for intestinal and hepatic diseases. We aim to provide new insights into the underexplored role of gut fungi in human health.

Metagenomics and metabolomics approaches in the study of Candida albicans colonization of host niches: a framework for finding microbiome-based antifungal strategies

In silico and experimental approaches have allowed an ever-growing understanding of the interactions within the microbiota. For instance, recently acquired data have increased knowledge of the mechanisms that support, in the gut and vaginal microbiota, the resistance to colonization by Candida albicans, an opportunistic fungal pathogen whose overgrowth can initiate severe infections in immunocompromised patients. Here, we review how bacteria from the microbiota interact with C. albicans. We show how recent OMICs-based pipelines, using metagenomics and/or metabolomics, have identified bacterial species and metabolites modulating C. albicans growth. We finally discuss how the combined use of cutting-edge OMICs-based and experimental approaches could provide new means to control C. albicans overgrowth within the microbiota and prevent its consequences.

Candida-bacterial cross-kingdom interactions

While the fungus Candida albicans is a common colonizer of healthy humans, it is also responsible for mucosal infections and severe invasive disease. Understanding the mechanisms that allow C. albicans to exist as both a benign commensal and as an invasive pathogen have been the focus of numerous studies, and recent findings indicate an important role for cross-kingdom interactions on C. albicans biology. This review highlights how C. albicans-bacteria interactions influence healthy polymicrobial community structure, host immune responses, microbial pathogenesis, and how dysbiosis may lead to C. albicans infection. Finally, we discuss how cross-kingdom interactions represent an opportunity to identify new antivirulence compounds that target fungal infections.

Unveiling Candida albicans intestinal carriage in healthy volunteers: the role of micro- and mycobiota, diet, host genetics and immune response

Candida albicans is a commensal yeast present in the gut of most healthy individuals but with highly variable concentrations. However, little is known about the host factors that influence colonization densities. We investigated how microbiota, host lifestyle factors, and genetics could shape C. albicans intestinal carriage in 695 healthy individuals from the Milieu Intérieur cohort. C. albicans intestinal carriage was detected in 82.9% of the subjects using quantitative PCR. Using linear mixed models and multiway-ANOVA, we explored C. albicans intestinal levels with regard to gut microbiota composition and lifestyle factors including diet. By analyzing shotgun metagenomics data and C. albicans qPCR data, we showed that Intestinimonas butyriciproducens was the only gut microbiota species whose relative abundance was negatively correlated with C. albicans concentration. Diet is also linked to C. albicans growth, with eating between meals and a low-sodium diet being associated with higher C. albicans levels. Furthermore, by Genome-Wide Association Study, we identified 26 single nucleotide polymorphisms suggestively associated with C. albicans colonization. In addition, we found that the intestinal levels of C. albicans might influence the host immune response, specifically in response to fungal challenge. We analyzed the transcriptional levels of 546 immune genes and the concentration of 13 cytokines after whole blood stimulation with C. albicans cells and showed positive associations between the extent of C. albicans intestinal levels and NLRP3 expression, as well as secreted IL-2 and CXCL5 concentrations. Taken together, these findings open the way for potential new interventional strategies to curb C. albicans intestinal overgrowth.

Tracking the fecal mycobiome through the lifespan of production pigs and a comparison to the feral pig

IMPORTANCE

This work provides evidence that early-life fungal community composition, or host genetics, influences long-term mycobiome composition. In addition, this work provides the first comparison of the feral pig mycobiome to the mycobiome of intensively raised pigs.

Commensal fungi in intestinal health and disease

The microbiota is known to influence several facets of mammalian development, digestion and disease. Most studies of the microbiota have focused on the bacterial component, but the importance of commensal fungi in health and disease is becoming increasingly clear. Although fungi account for a smaller proportion of the microbiota than bacteria by number, they are much larger and therefore account for a substantial proportion of the biomass. Moreover, as fungi are eukaryotes, their metabolic pathways are complex and unique. In this Review, we discuss the evidence for involvement of specific members of the mycobiota in intestinal diseases, including inflammatory bowel disease, colorectal cancer and pancreatic cancer. We also highlight the importance of fungal interactions with intestinal bacteria and with the immune system. Although most studies of commensal fungi have focused on their role in disease, we also consider the beneficial effects of fungal colonies in the gut. The evidence highlights potential opportunities to target fungi and their interactions for therapeutic purposes.

Overlooked Candida glabrata petites are echinocandin tolerant, induce host inflammatory responses, and display poor in vivo fitness

IMPORTANCE

Candida glabrata is a major fungal pathogen, which is able to lose mitochondria and form small and slow-growing colonies, called "petite." This attenuated growth rate has created controversies and questioned the clinical importance of petiteness. Herein, we have employed multiple omics technologies and in vivo mouse models to critically assess the clinical importance of petite phenotype. Our WGS identifies multiple genes potentially underpinning petite phenotype. Interestingly, petite C. glabrata cells engulfed by macrophages are dormant and, therefore, are not killed by the frontline antifungal drugs. Interestingly, macrophages infected with petite cells mount distinct transcriptomic responses. Consistent with our ex vivo observations, mitochondrial-proficient parental strains outcompete petites during systemic and gut colonization. Retrospective examination of C. glabrata isolates identified petite prevalence a rare entity, which can significantly vary from country to country. Collectively, our study overcomes the existing controversies and provides novel insights regarding the clinical relevance of petite C. glabrata isolates.

Decoding the host-pathogen interspecies molecular crosstalk during oral candidiasis in humans: an in silico analysis

Introduction: The objective of this study is to investigate the interaction between Candida albicans and human proteins during oral candidiasis, with the aim of identifying pathways through which the pathogen subverts host cells. Methods: A comprehensive list of interactions between human proteins and C. albicans was obtained from the Human Protein Interaction Database using specific screening criteria. Then, the genes that exhibit differential expression during oral candidiasis in C. albicans were mapped with the list of human-Candida interactions to identify the corresponding host proteins. The identified host proteins were further compared with proteins specific to the tongue, resulting in a final list of 99 host proteins implicated in oral candidiasis. The interactions between host proteins and C. albicans proteins were analyzed using the STRING database, enabling the construction of protein-protein interaction networks. Similarly, the gene regulatory network of Candida proteins was reconstructed using data from the PathoYeastract and STRING databases. Core module proteins within the targeted host protein-protein interaction network were identified using ModuLand, a Cytoscape plugin. The expression levels of the core module proteins under diseased conditions were assessed using data from the GSE169278 dataset. To gain insights into the functional characteristics of both host and pathogen proteins, ontology analysis was conducted using Enrichr and YeastEnrichr, respectively. Result: The analysis revealed that three Candida proteins, HHT21, CYP5, and KAR2, interact with three core host proteins, namely, ING4 (in the DNMT1 module), SGTA, and TOR1A. These interactions potentially impair the immediate immune response of the host against the pathogen. Additionally, differential expression analysis of fungal proteins and their transcription factors in Candida-infected oral cell lines indicated that Rob1p, Tye7p, and Ume6p could be considered candidate transcription factors involved in instigating the pathogenesis of oral candidiasis during host infection. Conclusion: Our study provides a molecular map of the host-pathogen interaction during oral candidiasis, along with potential targets for designing regimens to overcome oral candidiasis, particularly in immunocompromised individuals.

The global human gut microbiome: genes, lifestyles, and diet

A growing number of human gut microbiome studies consistently describe differences between human populations. Here, we review how factors related to host genetics, ethnicity, lifestyle, and geographic location help explain this variation. Studies from contrasting environmental scenarios point to diet and lifestyle as the most influential. The effect of human migration and displacement demonstrates how the microbiome adapts to newly adopted lifestyles and contributes to the profound biological and health consequences attributed to migration. This information strongly suggests against a universal scale for healthy or dysbiotic gut microbiomes, and prompts for additional microbiome population surveys, particularly from less industrialized nations. Considering these important differences will be critical for designing strategies to diagnose and restore dysbiosis in various human populations.

The role of fungi in the diagnosis of colorectal cancer

Colorectal cancer (CRC) is a prevalent tumour with high morbidity rates worldwide, and its incidence among younger populations is rising. Early diagnosis of CRC can help control the associated mortality. Fungi are common microorganisms in nature. Recent studies have shown that fungi may have a similar association with tumours as bacteria do. As an increasing number of tumour-associated fungi are discovered, this provides new ideas for the diagnosis and prognosis of tumours. The relationship between fungi and colorectal tumours has also been recently identified by scientists. Therefore, this paper describes the limitations and prospects of the application of fungi in diagnosing CRC and predicting CRC prognosis.

Escherichia coli Nissle 1917 Antagonizes Candida albicans Growth and Protects Intestinal Cells from C. albicans-Mediated Damage

Candida albicans is a pathobiont of the gastrointestinal tract. It can contribute to the diversity of the gut microbiome without causing harmful effects. When the immune system is compromised, C. albicans can damage intestinal cells and cause invasive disease. We hypothesize that a therapeutic approach against C. albicans infections can rely on the antimicrobial properties of probiotic bacteria. We investigated the impact of the probiotic strain Escherichia coli Nissle 1917 (EcN) on C. albicans growth and its ability to cause damage to intestinal cells. In co-culture kinetic assays, C. albicans abundance gradually decreased over time compared with C. albicans abundance in the absence of EcN. Quantification of C. albicans survival suggests that EcN exerts a fungicidal activity. Cell-free supernatants (CFS) collected from C. albicans-EcN co-culture mildly altered C. albicans growth, suggesting the involvement of an EcN-released compound. Using a model of co-culture in the presence of human intestinal epithelial cells, we further show that EcN prevents C. albicans from damaging enterocytes both distantly and through direct contact. Consistently, both C. albicans's filamentous growth and microcolony formation were altered by EcN. Taken together, our study proposes that probiotic-strain EcN can be exploited for future therapeutic approaches against C. albicans infections.

Lactobacillus murinus: A key factor in suppression of enterogenous Candida albicans infections in Compound Agrimony enteritis capsules-treated mice

ETHNOPHARMACOLOGICAL RELEVANCE

Compound Agrimony (FuFangXianHeCao, FFXHC) Enteritis Capsules is an ethnomedicine that is derived from Yi Nationality Herbal Medicine for enteritis treatment. We found that FFXHC reduced the mortality outcomes in enterogenic Candida albicans infected mice models and increased the abundance of Lactobacillus murinus in the intestines. Lactobacillus murinus exhibited comparable therapeutic effects to those of FFXHC in enterogenic Candida albicans infected mice. This study provides novel perspectives into the pharmacological mechanisms of FFXHC.

AIM OF THE STUDY

We investigated the mechanisms via which FFXHC inhibits C. albicans infections and its effects on L. murinus.

MATERIALS AND METHODS

Enterogenous C. albicans infection mice models were established and various parameters, including survival rate, weight change, number of colonies, treatment effects on intestinal mucosa, microecology, and immune cytokines evaluated. Susceptibility of C. albicans to L. murinus was evaluated in vitro.

RESULTS

Treatment with FFXHC reduced the number of colonies, improved the health status, enhanced the survival rates, increased the abundance of L. murinus, reduced damage to the intestinal mucosa, and elevated occludin as well as claudin-1 levels. Interestingly, TNF-α, IFN-γ, IL-10, IL-22, and IL-17A levels were increased while IL-1β levels were suppressed in the intestinal mucosa without any change in peripheral blood cytokine levels. Moreover, FFXHC promoted L. murinus proliferation. This study also confirmed the incubation-dependent anti-C. albicans effects exerted by the metabolic supernatants of L. murinus.

CONCLUSIONS

FFXHC effectively alleviated intestinal infections of C. albicans in mice and increased the abundance of L. murinus. Supplementation of L. murinus in food can achieve the effects that are comparable to those of FFXHC. Thus, L. murinus maybe essential in FFXHC-based treatment of intestinal C. albicans infections.

The interactions of Candida albicans with gut bacteria: a new strategy to prevent and treat invasive intestinal candidiasis

BACKGROUND

The gut microbiota plays an important role in human health, as it can affect host immunity and susceptibility to infectious diseases. Invasive intestinal candidiasis is strongly associated with gut microbiota homeostasis. However, the nature of the interaction between Candida albicans and gut bacteria remains unclear.

OBJECTIVE

This review aimed to determine the nature of interaction and the effects of gut bacteria on C. albicans so as to comprehend an approach to reducing intestinal invasive infection by C. albicans.

METHODS

This review examined 11 common gut bacteria's interactions with C. albicans, including Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Enterococcus faecalis, Staphylococcus aureus, Salmonella spp., Helicobacter pylori, Lactobacillus spp., Bacteroides spp., Clostridium difficile, and Streptococcus spp.

RESULTS

Most of the studied bacteria demonstrated both synergistic and antagonistic effects with C. albicans, and just a few bacteria such as P. aeruginosa, Salmonella spp., and Lactobacillus spp. demonstrated only antagonism against C. albicans.

CONCLUSIONS

Based on the nature of interactions reported so far by the literature between gut bacteria and C. albicans, it is expected to provide new ideas for the prevention and treatment of invasive intestinal candidiasis.

Overlooked Candida glabrata petites are echinocandin tolerant, induce host inflammatory responses, and display poor in vivo fitness

Small colony variants (SCVs) are relatively common among some bacterial species and are associated with poor prognosis and recalcitrant infections. Similarly, Candida glabrata - a major intracellular fungal pathogen - produces small and slow-growing respiratory-deficient colonies, termed "petite." Despite reports of clinical petite C . glabrata strains, our understanding of petite behavior in the host remains obscure. Moreover, controversies exist regarding in-host petite fitness and its clinical relevance. Herein, we employed whole-genome sequencing (WGS), dual-RNAseq, and extensive ex vivo and in vivo studies to fill this knowledge gap. WGS identified multiple petite-specific mutations in nuclear and mitochondrially-encoded genes. Consistent with dual-RNAseq data, petite C . glabrata cells did not replicate inside host macrophages and were outcompeted by their non-petite parents in macrophages and in gut colonization and systemic infection mouse models. The intracellular petites showed hallmarks of drug tolerance and were relatively insensitive to the fungicidal activity of echinocandin drugs. Petite-infected macrophages exhibited a pro-inflammatory and type I IFN-skewed transcriptional program. Interrogation of international C . glabrata blood isolates ( n =1000) showed that petite prevalence varies by country, albeit at an overall low prevalence (0-3.5%). Collectively, our study sheds new light on the genetic basis, drug susceptibility, clinical prevalence, and host-pathogen responses of a clinically overlooked phenotype in a major fungal pathogen.

Importance

Candida glabrata is a major fungal pathogen, which is able to lose mitochondria and form small and slow-growing colonies, called "petite". This attenuated growth rate has created controversies and questioned the clinical importance of petiteness. Herein, we have employed multiple omicstechnologies and in vivo mouse models to critically assess the clinical importance of petite phenotype. Our WGS identifies multiple genes potentially underpinning petite phenotype. Interestingly, petite C. glabrata cells engulfed by macrophages are dormant and therefore are not killed by the frontline antifungal drugs. Interestingly, macrophages infected with petite cells mount distinct transcriptomic responses. Consistent with our ex-vivo observations, mitochondrial-proficient parental strains outcompete petites during systemic and gut colonization. Retrospective examination of C. glabrata isolates identified petite prevalence a rare entity, can significantly vary from country to country. Collectively, our study overcomes the existing controversies and provides novel insights regarding the clinical relevance of petite C. glabrata isolates.

A probiotic nanozyme hydrogel regulates vaginal microenvironment for Candida vaginitis therapy

Molecular therapeutics are limited for Candida vaginitis because they damage normal cells and tissues of vagina, aggravating the imbalance of vaginal microbiota and increasing the recurrence. To tackle this limitation, through the combination of peroxidase-like rGO@FeS₂ nanozymes [reduced graphene oxide (rGO)] with Lactobacillus-produced lactic acid and H₂O₂, a responsive hyaluronic acid (HA) hydrogel rGO@FeS₂/Lactobacillus@HA (FeLab) is developed. FeLab has simultaneous anti-Candida albicans and vaginal microbiota-modulating activities. In particular, the hydroxyl radical produced from rGO@FeS₂ nanozymes and Lactobacillus kills C. albicans isolated from clinical specimens without affecting Lactobacillus. In mice with Candida vaginitis, FeLab has obvious anti-C. albicans activity but hardly damages vaginal mucosa cells, which is beneficial to vaginal mucosa repair. Moreover, a higher proportion of Firmicutes (especially Lactobacillus) and a decrease in Proteobacteria reshape a healthy vaginal microbiota to reduce the recurrence. These results provide a combined therapeutic of nanozymes and probiotics with translational promise for Candida vaginitis therapy.

Candida expansion in the gut of lung cancer patients associates with an ecological signature that supports growth under dysbiotic conditions

Candida species overgrowth in the human gut is considered a prerequisite for invasive candidiasis, but our understanding of gut bacteria promoting or restricting this overgrowth is still limited. By integrating cross-sectional mycobiome and shotgun metagenomics data from the stool of 75 male and female cancer patients at risk but without systemic candidiasis, bacterial communities in high Candida samples display higher metabolic flexibility yet lower contributional diversity than those in low Candida samples. We develop machine learning models that use only bacterial taxa or functional relative abundances to predict the levels of Candida genus and species in an external validation cohort with an AUC of 78.6-81.1%. We propose a mechanism for intestinal Candida overgrowth based on an increase in lactate-producing bacteria, which coincides with a decrease in bacteria that regulate short chain fatty acid and oxygen levels. Under these conditions, the ability of Candida to harness lactate as a nutrient source may enable Candida to outcompete other fungi in the gut.

Acetate modulates the inhibitory effect of Lactobacillus gasseri against the pathogenic yeasts Candida albicans and Candida glabrata

The exploration of the interference prompted by commensal bacteria over fungal pathogens is an interesting alternative to develop new therapies. In this work we scrutinized how the presence of the poorly studied vaginal species Lactobacillus gasseri affects relevant pathophysiological traits of Candida albicans and Candida glabrata. L. gasseri was found to form mixed biofilms with C. albicans and C. glabrata resulting in pronounced death of the yeast cells, while bacterial viability was not affected. Reduced viability of the two yeasts was also observed upon co-cultivation with L. gasseri under planktonic conditions. Either in planktonic cultures or in biofilms, the anti-Candida effect of L. gasseri was augmented by acetate in a concentration-dependent manner. During planktonic co-cultivation the two Candida species counteracted the acidification prompted by L. gasseri thus impacting the balance between dissociated and undissociated organic acids. This feature couldn't be phenocopied in single-cultures of L. gasseri resulting in a broth enriched in acetic acid, while in the co-culture the non-toxic acetate prevailed. Altogether the results herein described advance the design of new anti-Candida therapies based on probiotics, in particular, those based on vaginal lactobacilli species, helping to reduce the significant burden that infections caused by Candida have today in human health.