Opportunistic Fungal Pathogen Research Articles

Paint It Black: Staining of the Yeast Cryptococcus Neoformans with India Ink

Aims: To rectify the application of negative staining using India Ink dye in order to visualize the opportunistic yeast, Cryptococcus neoformans and its capsule. Discussion: The yeast C. neoformans is generally considered an opportunistic fungal pathogen due to its propensity to infect immunocompromised hosts, particularly those with HIV (+). This yeast responsible for causing severe disseminated Cryptococcus meningoencephalitis (CM) in humans. The type of clinical sample commonly sent for laboratory analysis of suspected patients is the cerebrospinal fluid (CSF) that usually obtained from spinal tap or lumbar puncture procedure. laboratory analysis to confirm CM initially by direct visualization of Cryptococci via light microscopy. Visualization of capsule, as the hallmark of C. neoformans is easy when appropriate number of yeasts are available in the clinical sample. India Ink is the dye of choice to stain C. neoformans and its capsule. The pathognomonic resemblance of its capsule is that of a halo appearance, whether thin or thick, surrounding the cell made visible by suspending the yeast in India ink preparations. Conclusion: India ink stain is still widely used for the detection of cryptococci in CSF, particularly in resource-limited laboratory/health service. Its sensitivity can be improved.

A correlative study of the genomic underpinning of virulence traits and drug tolerance of Candida auris.

Candida auris is an opportunistic fungal pathogen with high mortality rates which presents a clear threat to public health. The risk of C. auris infection is high because it can colonize the body, resist antifungal treatment, and evade the immune system. The genetic mechanisms for these traits are not well known. Identifying them could lead to new targets for new treatments. To this end, we present an analysis of the genetics and gene expression patterns of C. auris carbon metabolism, drug resistance, and macrophage interaction. We chose to study two C. auris isolates simultaneously, one drug sensitive (B11220 from Clade II) and one drug resistant (B11221 from Clade III). Comparing the genomes, we confirm the previously reported finding that B11220 was missing a 12.8 kb region on chromosome VI. This region contains a gene cluster encoding proteins related to alternative sugar utilization. We show that B11221, which has the gene cluster, readily assimilates and utilizes D-galactose and L-rhamnose as compared to B11220, which harbors the deletion. B11221 exhibits increased adherence and drug resistance compared to B11220 when grown in these sugars. Transcriptomic analysis of both isolates grown on glucose or galactose showed that the gene cluster was upregulated when grown on D-galactose. These findings reinforce growing evidence of a link between metabolism and drug tolerance. B11221 resists phagocytosis by macrophages and exhibits decreased β-1,3-glucan exposure, a key determinant that allows Candida to evade the host immune system, as compared to B11220. In a transcriptomic analysis of both isolates co-cultured with macrophages, we find upregulation of genes associated with transport and transcription factors in B11221. Our studies show a positive correlation between membrane composition and immune evasion, alternate sugar utilization, and drug tolerance in C. auris.

Spectrum of activity and mechanisms of azole-bisphosphonate synergy in pathogenic Candida.

Candida is a common and often very serious opportunistic fungal pathogen. Invasive candidiasis is a prevalent cause of nosocomial infections with a high mortality rate, and mucocutaneous infections significantly impact the quality of life of millions of patients a year. These infections pose substantial clinical challenges, particularly as the currently available antifungal treatment options are limited in efficacy and often toxic. Azoles are a mainstay of antifungal therapy and work by targeting the biosynthesis of ergosterol. However, there are rising rates of acquired azole resistance in various Candida species, and some species are considered intrinsically resistant to most azoles. Our research demonstrates the promising therapeutic potential of synergistically enhancing azoles with non-toxic, FDA-approved bisphosphonates. Repurposing bisphosphonates as antifungal synergists can bypass much of the drug development pipeline and accelerate the translation of azole-bisphosphonate combination therapy.

The porcine skin microbiome exhibits broad fungal antagonism

The skin and its microbiome function to protect the host from pathogen colonization and environmental stressors. In this study, using the Wisconsin Miniature Swine™ model, we characterize the porcine skin fungal and bacterial microbiomes, identify bacterial isolates displaying antifungal activity, and use whole-genome sequencing to identify biosynthetic gene clusters encoding for secondary metabolites that may be responsible for the antagonistic effects on fungi. Through this comprehensive approach of paired microbiome sequencing with culturomics, we report the discovery of novel species of Corynebacterium and Rothia. Further, this study represents the first comprehensive evaluation of the porcine skin mycobiome and the evaluation of bacterial-fungal interactions on this surface. Several diverse bacterial isolates exhibit potent antifungal properties against opportunistic fungal pathogens in vitro. Genomic analysis of inhibitory species revealed a diverse repertoire of uncharacterized biosynthetic gene clusters suggesting a reservoir of novel chemical and biological diversity. Collectively, the porcine skin microbiome represents a potential unique source of novel antifungals.

Host–pathogen interaction between the African fig fly, Zaprionus indianus, and its external mycobiome under laboratory conditions

AbstractThe African fig fly, Zaprionus indianus Gupta (Diptera: Drosophilidae), is an ecologically diverse pest species that interacts with and feeds on various microbial pathogens including bacteria and yeast found in decomposing fruits. However, the interaction of Z. indianus with its microbial community and microbial pathogens is obscure. To determine the presence of fungal pathogens, we collected wild Z. indianus from the northwestern part of the Indian subcontinent. Based on molecular identification and phylogenetic analysis, Debaryomyces hansenii (Zopf) Lodder & Kreger‐van Rij (isolate ziha1) was the most commonly observed fungus associated with Z. indianus. Furthermore, we identified two more opportunistic fungal pathogens: Aspergillus flavus Link (isolate zias2), and Pichia kudriavzevii Boidin, Pignal & Besson (isolate zibd3). The interaction of isolated fungi with Z. indianus was evaluated in terms of larval mortality, adult emergence, and fecundity. Debaryomyces hansenii ziha1 resulted in 90% emergence rate for adults, and did not cause significant mortality in the larval stage. In contrast, A. flavus zias2 and P. kudriavzevii zibd3 showed a significant reduction in fecundity and caused 99% and 74% larval mortality of Z. indianus, respectively. In the laboratory oviposition preference assay, mated females of Z. indianus preferred D. hansenii ziha1 supplemented food with a positive oviposition index compared to the uninfected control and compared to food infected with P. kudriavzevii zibd3 or A. flavus zias2. These findings underscore Z. indianus' potential to act as a reservoir for both symbiotic and pathogenic fungal species, some of which may be further harnessed for effective fruit fly pest control strategies.

Histone deacetylase Sir2 promotes the systemic Candida albicans infection by facilitating its immune escape via remodeling the cell wall and maintaining the metabolic activity.

Candida albicans (C. albicans) is the most common opportunistic fungal pathogen and can cause various superficial infections and even life-threatening systemic infections. To successfully propagate infection, this organism relies on the ability to express virulence-associated factors and escape host immunity. In this study, we demonstrated that the histone deacetylase Sir2 helps C. albicans adhere to host cells and escape host immunity by mediating cell wall remodeling; as a result, C. albicans successfully colonized and invaded the host in vivo. In addition, we found that Sir2 contributes to carbon utilization under hypoxic conditions, suggesting that Sir2 is important for C. albicans survival and the establishment of infection in hypoxic environments. In summary, we investigated the role of Sir2 in regulating C. albicans pathogenicity in detail; these findings provide a potential target for the development of antifungal drugs.

The Putative Cytochrome b5 Domain-Containing Protein CaDap1 Homologue Is Involved in Antifungal Drug Tolerance, Cell Wall Chitin Maintenance, and Virulence in Candida albicans.

Candida albicans (Ca), a prominent opportunistic fungal pathogen in humans, has garnered considerable attention due to its infectious properties. Herein, we have identified and characterized CaCDAP1 (Ca orf19.1034), a homolog of ScDAP1 found in Saccharomyces cerevisiae. CaCDAP1 encodes a 183-amino acid protein with a conserved cytochrome b5-like heme-binding domain. The deletion of CaDAP1 renders Ca cells susceptible to caspofungin and terbinafine. CaDAP1 deletion confers resistance to Congo Red and Calcofluor White, and sensitivity to sodium dodecyl sulfate. The deletion of CaDAP1 results in a 50% reduction in chitin content within the cell wall, the downregulation of phosphorylation levels in CaMkc1, and the upregulation of phosphorylation levels in CaCek1. Notably, CaDAP1 deletion results in the abnormal hyphal development of Ca cells and diminishes virulence in a mouse systemic infection model. Thus, CaDAP1 emerges as a critical regulator governing cellular responses to antifungal drugs, the synthesis of cell wall chitin, and virulence in Ca.

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.

Calcineurin-NFAT signaling controls neutrophils´ ability of chemoattraction upon fungal infection.

Calcineurin - nuclear factor of activated T-cell (CN-NFAT) inhibitors are widely clinically used drugs for immunosuppression but besides their required T-cell response inhibition, they also undesirably affect innate immune cells. Disruption of innate immune cell function can explain the observed susceptibility of CN-NFAT inhibitors-treated patients to opportunistic fungal infections. Neutrophils play an essential role in innate immunity as a defense against pathogens, however, the effect of CN-NFAT inhibitors on neutrophil function was poorly described. Thus, we tested the response of human neutrophils to opportunistic fungal pathogens, namely Candida albicans and Aspergillus fumigatus in the presence of CN-NFAT inhibitors. Here, we report that the NFAT pathway members were expressed in neutrophils and mediated part of the neutrophil response to pathogens. Upon pathogen exposure, neutrophils underwent profound transcriptomic changes with subsequent production of effector molecules. Importantly, genes and proteins involved in the regulation of the immune response and chemotaxis, including the chemokines CCL2, CCL3, and CCL4 were significantly upregulated. The presence of CN-NFAT inhibitors attenuated the expression of these chemokines and impaired the ability of neutrophils to chemoattract other immune cells. Our results amend knowledge about the impact of CN-NFAT inhibition in human neutrophils.

Microevolution of Candida glabrata (Nakaseomyces glabrata) during an infection

Candida glabrata (Nakaseomyces glabrata) is an emergent and opportunistic fungal pathogen that colonizes and persists in different niches within its human host. In this work, we studied five clinical isolates from one patient (P7), that have a clonal origin, and all of which come from blood cultures except one, P7-3, obtained from a urine culture. We found phenotypic variation such as sensitivity to high temperature, oxidative stress, susceptibility to two classes of antifungal agents, and cell wall porosity. Only isolate P7-3 is highly resistant to the echinocandin caspofungin while the other four isolates from P7 are sensitive. However, this same isolate P7-3, is the only one that displays susceptibility to fluconazole (FLC), while the rest of the isolates are resistant to this antifungal. We sequenced the PDR1 gene which encodes a transcription factor required to induce the expression of several genes involved in the resistance to FLC and found that all the isolates encode for the same Pdr1 amino acid sequence except for the last isolate P7-5, which contains a single amino acid change, G1099C in the putative Pdr1 transactivation domain. Consistent with the resistance to FLC, we found that the CDR1 gene, encoding the main drug efflux pump in C. glabrata, is highly overexpressed in the FLC-resistant isolates, but not in the FLC-sensitive P7-3. In addition, the resistance to FLC observed in these isolates is dependent on the PDR1 gene. Additionally, we found that all P7 isolates have a different proportion of cell wall carbohydrates compared to our standard strains CBS138 and BG14. In P7 isolates, mannan is the most abundant cell wall component, whereas β-glucan is the most abundant component in our standard strains. Consistently, all P7 isolates have a relatively low cell wall porosity compared to our standard strains.These data show phenotypic and genotypic variability between clonal isolates from different niches within a single host, suggesting microevolution of C. glabrata during an infection.

Lethal metabolism of Candida albicans respiratory mutants.

The destructive impact of fungi in agriculture and animal and human health, coincident with increases in antifungal resistance, underscores the need for new and alternative drug targets to counteract these trends. Cellular metabolism relies on many intermediates with intrinsic toxicity and promiscuous enzymatic activity generates others. Fuller knowledge of these toxic entities and their generation may offer opportunities of antifungal development. From this perspective our observation of media-conditional lethal metabolism in respiratory mutants of the opportunistic fungal pathogen Candida albicans was of interest. C. albicans mutants defective in NADH:ubiquinone oxidoreductase (Complex I of the electron transport chain) exhibit normal growth in synthetic complete medium. In YPD medium, however, the mutants grow normally until early stationary phase whereupon a dramatic loss of viability occurs. Upwards of 90% of cells die over the subsequent four to six hours with a loss of membrane integrity. The extent of cell death was proportional to the amount of BactoPeptone, and to a lesser extent, the amount of yeast extract. YPD medium conditioned by growth of the mutant was toxic to wild-type cells indicating mutant metabolism established a toxic milieu in the media. Conditioned media contained a volatile component that contributed to toxicity, but only in the presence of a component of BactoPeptone. Fractionation experiments revealed purine nucleosides or bases as the synergistic component. GC-mass spectrometry analysis revealed acetal (1,1-diethoxyethane) as the active volatile. This previously unreported and lethal synergistic interaction of acetal and purines suggests a hitherto unrecognized toxic metabolism potentially exploitable in the search for antifungal targets.

Allergic bronchopulmonary mycosis due to Schizophyllum commune in a patient with chronic hepatitis B.

Schizophyllum commune (S. commune) is an opportunistic pathogenic fungus and can cause infection of the respiratory system in immunocompromised hosts. Allergic bronchopulmonary mycosis (ABPM) is the major disease caused by S. commune. However, identification of S. commune using routine mycological diagnostic methods is difficult. It is easy to make mistakes in diagnosis and treatment, resulting in deterioration of the disease. We report the first case of ABPM due to S. commune in a Chinese patient with chronic hepatitis B. The patient presented cough, sputum and dyspnea for six months. The pathogen was missed during routine laboratory workup. We performed bronchoscopy examination and bronchoalveolar lavage. S. commune was identified by metagenomic next-generation sequencing (mNGS) of bronchial alveolar lavage fluid (BALF). Hence, the patient was immediately treated with 200 mg voriconazole twice daily (intravenous infusion) and 20 mg prednisone once a day (oral therapy), along with oral entecavir for hepatitis B. There was no recurrence of infection after the medication was discontinued. S. commune infection should be considered in the diagnosis of patients with refractory cough, sputum and dyspnea, especially in immunocompromised individuals. The mNGS technique is an effective supplementary technique for the diagnosis of S. commune infection, enabling precise clinical decision-making and appropriate treatment. Most patients have good prognosis with a combination of proper antifungal therapy and hormonal therapy.

Morphology, Development, and Pigment Production of Talaromyces marneffei are Diversely Modulated Under Physiologically Relevant Growth Conditions.

Talaromyces marneffei is an opportunistic pathogenic fungus that mainly affects HIV-positive individuals endemic to Southeast Asia and China. Increasing efforts have been made in the pathogenic mechanism and host interactions understanding of this pathogen in the last two decades; however, there are still no conclusions on how T. marneffei was transmitted from the donor bamboo rats to humans. A perception that the failure of fungus isolation from soil was attributed to the low salt tolerance of T. marneffei. Therefore, the effect of environmental fluctuations in fungal growth and development is fundamental for the characterization of its origin and fungal biology understanding. Herein, we characterized high osmolarity, pH, metal ions, nutrients, and oxidative stress have versatile effects on T. marneffei hyphal or yeast growth, conidia generation, and pigment production. Among these, high pH, low glucose amounts, and the inorganic nitrogen ammonium tartrate stimulated the red pigment production, whereas high osmolarity, high pH, and the inorganic nitrogen sodium nitrate could significantly accelerate the conidia generation. Specifically, zinc starvation repressed conidia generation and prevented the wrinkled yeast colony formation, indicating the function of zinc regulators in pathogenicity regulation. Since conidia are recognized as the infectious propagules, the effects characterization of different environmental factors in T. marneffei morphology in this work will not only expand the growth and pathogenic biology understanding of the fungus but also provide more clues for the T. marneffei infection transmission origin investigation.

Oral Rinses: Some Kill and Some Cripple Candida albicans

Introduction: Oral healthcare professionals play a crucial role in guiding patients toward evidence-based choices among the many available oral rinses. In this study, we explored how specific oral rinse formulations affect the viability and modulate critical virulence traits of the opportunistic fungal pathogen Candida albicans. Materials and Methods: We assessed the effects of these oral rinses on the production of germ tube, production of phospholipase and hemolysin, as well as biofilm formation. Results: We found that oral rinses containing cetylpyridinium chloride (CPC) and chlorhexidine (CHX) showed the greatest fungicidal activity with the lowest minimum fungicidal concentrations (0.38% and 0.78%, respectively). Oral rinses based on zinc chloride and sodium fluoride with Miswak bark extract (MIS) or essential oils (EO) had much lower fungicidal activity (8–16 times lower) compared to CHX and CPC. However, they had a significantly greater impact on the virulence traits of C. albicans. They reduced germ tube production by 86–89% (vs. 42% for CHX and 29% for CPC), completely inhibited phospholipase and hemolysin production, and together with the CPC-based oral rinse, exerted the greatest reductions in biofilm formation across all tested concentrations. This was in contrast to both the controls and CHX, which had a minimal effect on biofilm formation. Conclusion: By inhibiting the virulence factors, the oral rinse can have a crippling effect on C. albicans, weakening this opportunistic pathogen and hindering its potential to cause infection.

Loss of the scavenger receptor MARCO results in uncontrolled vomocytosis of fungi from macrophages.

Vomocytosis, also known as nonlytic exocytosis, is a process whereby fully phagocytosed microbes are expelled from phagocytes without discernible damage to either the phagocyte or microbe. Although this phenomenon was first described in the opportunistic fungal pathogen Cryptococcus neoformans in 2006, to date, mechanistic studies have been hampered by an inability to reliably stimulate or inhibit vomocytosis. Here we present the fortuitous discovery that macrophages lacking the scavenger receptor MAcrophage Receptor with COllagenous domain (MARCO), exhibit near-total vomocytosis of internalised cryptococci within a few hours of infection. Marco-/- macrophages also showed elevated vomocytosis of a yeast-locked C. albicans strain, suggesting this to be a broadly relevant observation. We go on to show that MARCO's role in modulating vomocytosis is independent of its role as a phagocytic receptor, suggesting that this protein may play an important and hitherto unrecognised role in modulating macrophage behaviour.

Alterations of lung microbiota in lung transplant recipients with pneumocystis jirovecii pneumonia

BackgroundIncreasing evidence revealed that lung microbiota dysbiosis was associated with pulmonary infection in lung transplant recipients (LTRs). Pneumocystis jirovecii (P. jirovecii) is an opportunistic fungal pathogen that frequently causes lethal pneumonia in LTRs. However, the lung microbiota in LTRs with P. jirovecii pneumonia (PJP) remains unknow.MethodsIn this prospective observational study, we performed metagenomic next-generation sequencing (mNGS) on 72 bronchoalveolar lavage fluid (BALF) samples from 61 LTRs (20 with PJP, 22 with PJC, 19 time-matched stable LTRs, and 11 from LTRs after PJP recovery). We compared the lung microbiota composition of LTRs with and without P. jirovecii, and analyzed the related clinical variables.ResultsBALFs collected at the episode of PJP showed a more discrete distribution with a lower species diversity, and microbiota composition differed significantly compared to P. jirovecii colonization (PJC) and control group. Human gammaherpesvirus 4, Phreatobacter oligotrophus, and Pseudomonas balearica were the differential microbiota species between the PJP and the other two groups. The network analysis revealed that most species had a positive correlation, while P. jirovecii was correlated negatively with 10 species including Acinetobacter venetianus, Pseudomonas guariconensis, Paracandidimonas soli, Acinetobacter colistiniresistens, and Castellaniella defragrans, which were enriched in the control group. The microbiota composition and diversity of BALF after PJP recovery were also different from the PJP and control groups, while the main components of the PJP recovery similar to control group. Clinical variables including age, creatinine, total protein, albumin, IgG, neutrophil, lymphocyte, CD3+CD45+, CD3+CD4+ and CD3+CD8+ T cells were deeply implicated in the alterations of lung microbiota in LTRs.ConclusionsThis study suggests that LTRs with PJP had altered lung microbiota compared to PJC, control, and after recovery groups. Furthermore, lung microbiota is related to age, renal function, nutritional and immune status in LTRs.

A Comparative Study of The Effects of Sumac Aqueous and Ethanol Extracts on Candida Albicans in Laboratory Conditions

Background and purpose: Candida albicans is an opportunistic pathogenic fungus that is considered a member of the human intestinal flora that can survive outside the human body. This fungus is usually a harmless organism, but it can become pathogenic in immunocompromised people under various conditions. For oral infections, treatment with topical clotrimazole or nystatin is usually effective. In case of failure, oral or intravenous fluconazole, itraconazole or amphotericin B may be used. Several topical antifungal medications may be used for vaginal infections, including clotrimazole. This study was conducted to investigate the effect of sumac aqueous and ethanol extracts on Candida albicans. Methods: In this experimental study, aqueous and alcoholic sumac extracts were prepared and different concentrations were prepared to investigate their effect on Candida albicans. The negative control included the culture medium without mushrooms and the positive control included mushrooms without extract. Candida albicans fungus was cultured after 24, 48 and 72 hours, and control drug concentrations for fluconazole were 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32 on Candida albicans. The effect was given. Methods: In this experimental study, aqueous and alcoholic sumac extracts were prepared and different concentrations were prepared to investigate their effect on Candida albicans. The negative control included the culture medium without mushrooms and the positive control included mushrooms without extract. Candida albicans fungus was cultured after 24, 48 and 72 hours, and control drug concentrations for fluconazole were 32, 16, 8, 4, 2, 1, 0.5, 0.25, 0.125 millilitres per milligram on Candida albicans. The effect was given. Results: After the cultivation of Candida albicans mushroom and examination, it was found that this mushroom can grow in all concentrations of aqueous extract of the sumac plant and none of the tested concentrations can prevent its growth, and the alcoholic extract at a concentration of 60 mg/ml can inhibit growth. MIC) of Candida albicans fungus, but the fungus was able to grow in other concentrations. The concentration of 0.5 mg/ml of the commercial antibiotic fluconazole could inhibit the growth (MIC) of this fungus. Conclusion: While different concentrations of aqueous and alcoholic extracts of the sumac plant were investigated and it was found that aqueous extract has no effect and alcoholic extract is effective in the same concentration, more and more comprehensive studies are suggested in laboratory scale and living organisms.

Antifungal Activity of Moringa peregrina Plant Extracts Against Candida kruzei

Commercial antibacterial drugs commonly used to treat diseases have led to the current drug resistance in humans. Early human civilizations used Moringa peregrina extracts against a variety of illnesses and infections caused by food. M. Peregrina grows well in a variety of harsh conditions, including high temperatures, limited water supply, and nutrient-deficient soils. There is something remarkable about this plant's resilience and ability to survive in challenging environments. To conserve water and withstand extreme drought conditions, it has evolved unique adaptations. M. peregrina's deciduous leaves allow it to shed its leaves during dry periods to reduce water loss through transpiration. As a result of this adaptation, it is able to endure prolonged periods of water scarcity. A serious infection can be caused by Candida kruzei, an opportunistic fungal pathogen that is especially dangerous to immuno-compromised individuals, and the increasing drug-resistance of several Candida strains have necessitated the search for alternative to standard anti-fungal agents to which resistance has grown. The objective of this study was to investigate the antifungal effect of M. peregrina ethanolic extract derived from its leaves, seeds, and roots against C. kruzei. The phytochemical screening of M. peregrina extracts were performed using qualitative determination whilst the antifungal activity of methanol and water extracts of leaves, seeds, and roots was performed using the agar diffusion method. The results of the phytochemical analysis demonstrated the presence of phenolic compounds, steroids, flavonoids, tannins, and saponins. The studied extracts displayed various degrees of antifungal activities against C. kruzei. The extract of the leaves was active against C. kruzei with recorded minimal inhibitory concentration (MIC) of 10mg/ml. There is a need for further research to isolate and identify the antimicrobial agent in different parts of M. peregrina. A deeper investigation should be conducted into the antibacterial agent dosages of these plant parts, which may then be used by the pharmaceutical industry.

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.

Borneol serves as an adjuvant agent to promote the cellular uptake of curcumin for enhancing its photodynamic fungicidal efficacy against Candida albicans

Candida albicans (C. albicans), a major opportunistic pathogenic fungus, is known to cause superficial skin infections. Unfortunately, the misuse of antibiotics has led to the emergence of drug resistance in fungi. Antimicrobial photodynamic therapy (aPDT), a non-antibiotic alternative, has shown potential in treating drug-resistant fungal infections. Curcumin is a photodynamically active phytochemical whose photodynamic fungicidal efficacy is largely dependent on its intracellular accumulation. However, curcumin faces challenges in penetrating the cytoplasm due to its poor water solubility and the fungal cell wall. Borneol, another monoterpenoid phytochemical, is known for its ability to enhance drug absorption. In this study, we showed that borneol improved the cellular uptake of curcumin, thereby enhancing its photodynamic fungicidal efficacy against C. albicans. This effect was attributed to borneol's ability to increase cell permeability. Transcriptomic analysis further confirmed that borneol disrupted the normal structure and function of the C. albicans cell wall and membrane, resulting in dysregulated mRNA expression of related genes and ultimately increased cell permeability. As a result, the excessive accumulation of curcumin in C. albicans triggered the overproduction of intracellular ROS upon exposure to blue light. These excessive intracellular ROS disrupted various cellular structures, interfered with essential cellular processes, inhibited biofilm formation and reduced virulence. Remarkably, borneol was also found to enhance curcumin uptake by C. albicans within biofilms, further enhancing the anti-biofilm efficacy of curcumin-mediated aPDT (Cur-aPDT). In conclusion, the results of this study strongly support the potential of borneol as an adjuvant agent to Cur-aPDT in treating superficial cutaneous fungal infections.