Candida albicans - Biology, molecular characterization, pathogenicity, and advances in diagnosis and control – An update

Oral Health and Nutraceutical Agents

Oral health is essential for both overall health and quality of life. The mouth is a window into the body's health, and nutrition can strongly impact the state of general and oral health. A healthy diet involves the synergistic effect of various nutraceutical agents, potentially capable of conferring protective actions against some inflammatory and chronic-degenerative disorders. Nutraceuticals, mostly present in plant-derived products, present multiple potential clinical, preventive, and therapeutic benefits. Accordingly, preclinical and epidemiological studies suggested a protective role for these compounds, but their real preventive and therapeutic effects in humans still await confirmation. Available evidence suggests that plant extracts are more effective than individual constituents because they contain different phytochemicals with multiple pharmacological targets and additive/synergistic effects, maximizing the benefits for oral health. Moreover, nutritional recommendations for oral health should be personalized and aligned with valid suggestions for overall health. This review is aimed to: introduce the basic concepts of nutraceuticals, including their main food sources; examine the logic that supports their relationship with oral health, and summarize and critically discuss clinical trials testing the utility of nutraceuticals in the prevention and treatment of oral diseases.

Invasive candidiasis in dogs: A case report and review of the literature

Invasive candidiasis is characterized by the systemic dissemination of Candida spp. and colonization of multiple organs. We are reporting a case of invasive candidiasis in a 3.5-year-old female mixed-breed dog with a history of limb injury. After clinical evaluation and complementary examinations a sepsis diagnose was established. The patient remained hospitalized under antibiotic therapy, dying three days later. Necropsy revealed white, nodular (pyogranulomas), and multifocal areas on the liver, button ulcers in the stomach and intestines, and a random lung consolidation. Impression smears were made from the liver and lung surface lesions during necropsy showing yeast and pseudohyphae structures. Fragments of these organs were sent for fungal culture and subsequent molecular etiologic characterization, identifying it as Candida albicans. Histological examination of different organs showed pyogranulomatous inflammation surrounding the necrosis areas, which were full of yeast and pseudohyphae, as evidenced by periodic acid Schiff and immunohistochemistry. Neutropenia, as a consequence of sepsis, associated with the use of antibiotics may have allowed yeast invasion and proliferation in the mucosa of the gastrointestinal tract, reaching the liver and lungs through hematogenous route. Invasive candidiasis is a rare canine disease, and no other cases of neutropenia associated with antibiotic therapy, as a predisposing factors, have been reported.

Antifungal Synergy: Mechanistic Insights into the R-1-R Peptide and Bidens pilosa Extract as Potent Therapeutics against Candida spp. through Proteomics

Previous reports have demonstrated that the peptide derived from LfcinB, R-1-R, exhibits anti-Candida activity, which is enhanced when combined with an extract from the Bidens pilosa plant. However, the mechanism of action remains unexplored. In this research, a proteomic study was carried out, followed by a bioinformatic analysis and biological assays in both the SC5314 strain and a fluconazole-resistant isolate of Candida albicans after incubation with R-1-R. The proteomic data revealed that treatment with R-1-R led to the up-regulation of most differentially expressed proteins compared to the controls in both strains. These proteins are primarily involved in membrane and cell wall biosynthesis, membrane transport, oxidative stress response, the mitochondrial respiratory chain, and DNA damage response. Additionally, proteomic analysis of the C. albicans parental strain SC5314 treated with R-1-R combined with an ethanolic extract of B. pilosa was performed. The differentially expressed proteins following this combined treatment were involved in similar functional processes as those treated with the R-1-R peptide alone but were mostly down-regulated (data are available through ProteomeXchange with identifier PXD053558). Biological assays validated the proteomic results, evidencing cell surface damage, reactive oxygen species generation, and decreased mitochondrial membrane potential. These findings provide insights into the complex antifungal mechanisms of the R-1-R peptide and its combination with the B. pilosa extract, potentially informing future studies on natural product derivatives.

Metabolic Patterns of Fluconazole Resistant and Susceptible Candida auris Clade V and I

Candida auris, an emerging non-albicans multidrug-resistant yeast, has become a significant cause of invasive candidiasis in healthcare settings. So far, data on the metabolites of C. auris in different clades are minimal, and no studies have focused on clade V metabolites. Therefore, Gas chromatography-mass spectrometry (GC-MS) was used for the metabolomic profiling of clade I C. auris compared with fluconazole-resistant and susceptible C. auris in clade V strains. GC-MS chromatography revealed 28, 22, and 30 compounds in methanolic extracts of the fluconazole-susceptible and fluconazole-resistant C. auris clade V and C. auris clade I strain, respectively. Some compounds, such as acetamide and metaraminol, were found in fluconazole-susceptible and resistant C. auris clade V and clade I. N-methyl-ethanamine and bis(2-ethylhexyl) phthalate metabolites were found in both fluconazole -susceptible and resistant C. auris clade V, as well as 3-methyl-4-isopropylphenol, 3,5-bis(1,1-dimethyl)-1,2-benzenediol, and diisostyl phthalate metabolites in both fluconazole resistant C. auris clade V and I. Identifying these metabolites contributes to understanding the morphogenesis and pathogenesis of C. auris, highlighting their potential role in antifungal drug resistance and the control of fungal growth. However, further experiments are warranted to fully comprehend the identified metabolites' regulatory responses, and there may be potential challenges in translating these findings into clinical applications.

Candida albicans cDNA library screening reveals novel potential diagnostic targets for invasive candidiasis

The detection of patterns associated with the invasive form of Candida albicans, such as Candida albicans germ tube antibodies (CAGTA), is a useful complement to blood culture for Invasive Candidiasis (IC) diagnosis. As CAGTA are detected by a non-standardisable and non-automatable technique, a Candida albicans cDNA expression library was screened with CAGTA isolated from serum of an animal model of invasive candidiasis, and five protein targets were identified: hyphally regulated cell wall protein 1 (Hyr1), enolase 1 (Eno1), coatomer subunit gamma (Sec21), a metallo-aminopeptidase (Ape2) and cystathionine gamma-lyase (Cys3). Homology with proteins from other organisms rules out Cys3 as a good biomarker while Sec21 results suggest that it is not in the germ tubes surface but secreted to the external environment. Our analysis propose Ape2, Sec21 and a region of Hyr1 different from the one currently being studied for immunoprotection as potential biomarker candidates for the diagnosis of IC.

Candida albicans-A systematic review to inform the World Health Organization Fungal Priority Pathogens List

Candida albicans is a common fungal pathogen and amongst the leading causes of invasive candidiasis globally. This systematic review examines the characteristics and global impact of invasive infections caused by C. albicans. We searched on PubMed and Web of Science for studies reporting on criteria such as mortality, morbidity, drug resistance, preventability, yearly incidence, and distribution/emergence during the period from 2016 to 2021. Our findings indicate that C. albicans is the most common Candida species causing invasive disease and that standard infection control measures are the primary means of prevention. However, we found high rates of mortality associated with infections caused by C. albicans. Furthermore, there is a lack of data on complications and sequelae. Resistance to commonly used antifungals remains rare. Although, whilst generally susceptible to azoles, we found some evidence of increasing resistance, particularly in middle-income settings-notably, data from low-income settings were limited. Candida albicans remains susceptible to echinocandins, amphotericin B, and flucytosine. We observed evidence of a decreasing proportion of infections caused by C. albicans relative to other Candida species, although detailed epidemiological studies are needed to confirm this trend. More robust data on attributable mortality, complications, and sequelae are needed to understand the full extent of the impact of invasive C. albicans infections.

Towards a better understanding of the effect of protein conditioning layers on microbial adhesion: a focused investigation of fibronectin and bovine serum albumin layers on SiO2 surfaces

The interaction of foreign implants with their surrounding environment is significantly influenced by the adsorption of proteins on the biomaterial surfaces, playing a role in microbial adhesion. Therefore, understanding protein adsorption on solid surfaces and its effect on microbial adhesion is essential to assess the associated risk of infection. The aim of this study is to evaluate the effect of conditioning by fibronectin (Fn) or bovine serum albumin (BSA) protein layers of silica (SiO2) surfaces on the adhesion and detachment of two pathogenic microorganisms: Pseudomonas aeruginosa PAO1-Tn7-gfp and Candida albicans CIP 48.72. Experiments are conducted under both static and hydrodynamic conditions using a shear stress flow chamber. Through the use of very low wall shear stresses, the study brings the link between the static and dynamic conditions of microbial adhesion. The results reveal that the microbial adhesion critically depends on: (i) the presence of a protein layer conditioning the SiO2 surface, (ii) the type of protein and (iii) the protein conformation and organization in the conditioning layer. In addition, a very distinct adhesion behaviour of P. aeruginosa is observed towards the two tested proteins, Fn and BSA. This effect is reinforced by the amount of proteins adsorbed on the surface and their organization in the layer. The results are discussed in the light of atomic force microscopy analysis of the organization and conformation of proteins in the layers after adsorption on the SiO2 surface, as well as the specificity in bacterial behaviour when interacting with these protein layers. The study also demonstrates the very distinctive behaviours of the prokaryote P. aeruginosa PAO1-Tn7-gfp compared to the eukaryote C. albicans CIP 48.72. This underscores the importance of considering species-specific interactions between the protein conditioning layer and different pathogenic microorganisms, which appear crucial in designing tailored anti-adhesive surfaces.

Antifungal activity of ruthenium (II) complex combined with fluconazole against drug-resistant Candida albicans in vitro and its anti-invasive infection in vivo

With the abuse of antibiotics and azoles, drug-resistant Candida albicans infections have increased sharply and are spreading rapidly, thereby significantly reducing the antifungal efficacy of existing therapeutics. Several patients die of fungal infections every year. Therefore, there is an urgent requirement to develop new drugs. Accordingly, we synthesized a series of polypyridyl ruthenium (II) complexes having the formula [Ru (NN)2 (bpm)] (PF6)2 (N-N = 2,2'-bipyridine) (bpy, in Ru1), 1,10-phenanthroline (phen, in Ru2), 4,7-diphenyl-1,10-phenanthroline (DIP, in Ru3) (bpm = 2,2'-bipyrimidine) and studied their antifungal activities. Ru3 alone had no effect on the drug-resistant strains, but Ru3 combined with fluconazole (FLC) exhibited significant antifungal activity on drug-resistant strains. A high-dose combination of Ru3 and FLC exhibited direct fungicidal activity by promoting the accumulation of reactive oxygen species and damaging the cellular structure of C. albicans. Additionally, the combination of Ru3 and FLC demonstrated potent antifungal efficacy in vivo in a mouse model of invasive candidiasis. Moreover, the combination significantly improved the survival state of mice, restored their immune systems, and reduced renal injury. These findings could provide ideas for the development of ruthenium (II) complexes as novel antifungal agents for drug-resistant microbial stains.

Antifungal activity of a trypsin inhibitor from Salvia hispanica L. (chia) seeds against fluconazole-resistant strains of Candida spp. and evaluation of its toxicity in vitro

The incidence of Candida species resistant to traditional antifungal drugs is increasing globally. This issue significantly impacts patients' lives and increases healthcare expenses, confirming the need to develop novel therapeutic strategies. Recently, a thermostable trypsin inhibitor named ShTI (11.558 kDa), which has antibacterial effects on Staphylococcus aureus, was isolated from Salvia hispanica L. (chia) seeds. This study aimed to assess the antifungal effect of ShTI against Candida species and its synergism with fluconazole and to evaluate its mode of action. Preliminary toxicological studies on mouse fibroblasts were also performed. ShTI exhibited antifungal effects against C. parapsilosis (ATCC® 22,019), C. krusei (ATCC® 6258), and six clinical fluconazole-resistant strains of C. albicans (2), C. parapsilosis (2), and C. tropicalis (2). The minimum inhibitory concentration (MIC) values were 4.1 µM (inhibiting 50% of the isolates) and 8.2 µM (inhibiting 100% of the isolates). Additionally, when combined with fluconazole, ShTI had a synergistic effect on C. albicans, altering the morphological structure of the yeast. The mode of action of ShTI against C. krusei (ATCC® 6258) and C. albicans involves cell membrane permeabilization, the overproduction of reactive oxygen species, the formation of pseudohyphae, pore formation, and consequently, cell death. In addition, ShTI (8.65 and 17.3 µM) had noncytotoxic and nongenotoxic effects on L929 mouse fibroblasts. These findings suggest that ShTI could be a promising antimicrobial candidate, but further research is necessary to advance its application as a novel antifungal agent.

Antifungal Plant Defensins as an Alternative Tool to Combat Candidiasis

Currently, the spread of fungal infections is becoming an urgent problem. Fungi of the Candida genus are opportunistic microorganisms that cause superficial and life-threatening systemic candidiasis in immunocompromised patients. The list of antifungal drugs for the treatment of candidiasis is very limited, while the prevalence of resistant strains is growing rapidly. Therefore, the search for new antimycotics, including those exhibiting immunomodulatory properties, is of great importance. Plenty of natural compounds with antifungal activities may be extremely useful in solving this problem. This review evaluates the features of natural antimicrobial peptides, namely plant defensins as possible prototypes of new anticandidal agents. Plant defensins are important components of the innate immune system, which provides the first line of defense against pathogens. The introduction presents a brief summary regarding pathogenic Candida species, the pathogenesis of candidiasis, and the mechanisms of antimycotic resistance. Then, the structural features of plant defensins, their anticandidal activities, their mechanisms of action on yeast-like fungi, their ability to prevent adhesion and biofilm formation, and their combined action with conventional antimycotics are described. The possible mechanisms of fungal resistance to plant defensins, their cytotoxic activity, and their effectiveness in in vivo experiments are also discussed. In addition, for the first time for plant defensins, knowledge about their immunomodulatory effects is also presented.

Ascomycetes yeasts: The hidden part of human microbiome

The fungal component of the microbiota, the mycobiota, has been neglected for a long time due to its poor richness compared to bacteria. Limitations in fungal detection and taxonomic identification arise from using metagenomic approaches, often borrowed from bacteriome analyses. However, the relatively recent discoveries of the ability of fungi to modulate the host immune response and their involvement in human diseases have made mycobiota a fundamental component of the microbial communities inhabiting the human host, deserving some consideration in host-microbe interaction studies and in metagenomics. Here, we reviewed recent data on the identification of yeasts of the Ascomycota phylum across human body districts, focusing on the most representative genera, that is, Saccharomyces and Candida. Then, we explored the key factors involved in shaping the human mycobiota across the lifespan, ranging from host genetics to environment, diet, and lifestyle habits. Finally, we discussed the strengths and weaknesses of culture-dependent and independent methods for mycobiota characterization. Overall, there is still room for some improvements, especially regarding fungal-specific methodological approaches and bioinformatics challenges, which are still critical steps in mycobiota analysis, and to advance our knowledge on the role of the gut mycobiota in human health and disease. This article is categorized under: Immune System Diseases > Genetics/Genomics/Epigenetics Immune System Diseases > Environmental Factors Infectious Diseases > Environmental Factors.

New azole derivatives linked to indole/indoline moieties combined with FLC against drug-resistant Candida albicans

Candida albicans is the most common fungal pathogen associated with human opportunistic infections. Invasive infections caused by C. albicans are becoming increasingly serious. However, with the rising incidence of fungal infection, many fungi are resistant to commonly used drugs. Therefore, there is an urgent need for exploring new anti-fungal drugs that fungi are not resistant to. A series of novel azole derivatives linked to indole/indoline moieties were prepared, and in vitro antifungal activity evaluated. All compounds combined with FLC showed excellent activity against drug-resistant C. albicans with low toxicity. A preliminary mechanistic study indicated that S1 combined with FLC could inhibit the formation of C. albicans biofilms as well as destroy the integrity of cell-membrane structure and mitochondrial function. S1 could be considered a new fungal agent for further study.

Effect of tryptophan position and lysine/arginine substitution in antimicrobial peptides on antifungal action

Every year, the overprescription, misuse, and improper disposal of antibiotics have led to the rampant development of drug-resistant pathogens and, in turn, a significant increase in the number of patients who die of drug-resistant fungal infections. Recently, researchers have begun investigating the use of antimicrobial peptides (AMPs) as next-generation antifungal agents to inhibit the growth of drug-resistant fungi. The antifungal activity of alpha-helical peptides designed using the cationic amino acids containing lysine and arginine and the hydrophobic amino acids containing isoleucine and tryptophan were evaluated using 10 yeast and mold fungi. Among these peptides, WIK-14, which is composed of a 14-mer with tryptophan sequences at the amino terminus, showed the best antifungal activity via transient pore formation and ROS generation. In addition, the in vivo antifungal effects of WIK-14 were investigated in a mouse model infected with drug-resistant Candida albicans. The results demonstrate the potential of AMPs as antifungal agents.

Antifungal activity against Candida albicans of methyl 3,5-dinitrobenzoate loaded nanoemulsion

The objective of this study was to evaluate the antifungal activity of free methyl 3,5 dinitrobenzoate (MDNB) and its nanoemulsion (MDNB-NE) against strains of Candida albicans. Additionally, a molecular modeling study was also carried out to propose the mechanism of action and toxicity of MDNB. These results demonstrated the MDNB-NE presented a droplet size of 181.16 ± 3.20 nm and polydispersity index of 0.30 ± 0.03. MDNB and MDNB-NE inhibited the growth of all strains with minimum inhibitory concentrations of 0.27-1.10 mM. The biological results corroborated the molecular model, which pointed to a multi-target antifungal mechanism of action for MDNB in C. albicans. The study could serve as a basis for further research involving compounds with nitro groups with antifungal.

Macrophage pyroptosis induced by Candida albicans

Candida albicans (C. albicans) is a prevalent opportunistic pathogen that causes mucocutaneous and systemic infections, particularly in immunocompromised individuals. Macrophages play a crucial role in eliminating C. albicans in local and bloodstream contexts, while also regulating antifungal immune responses. However, C. albicans can induce macrophage lysis through pyroptosis, a type of regulated cell death. This process can enable C. albicans to escape from immune cells and trigger the release of IL-1β and IL-18, which can impact both the host and the pathogen. Nevertheless, the mechanisms by which C. albicans triggers pyroptosis in macrophages and the key factors involved in this process remain unclear. In this review, we will explore various factors that may influence or trigger pyroptosis in macrophages induced by C. albicans, such as hypha, ergosterol, cell wall remodeling, and other virulence factors. We will also examine the possible immune response following macrophage pyroptosis.

Formulation and Development of a Herbal Antifungal Gel Containing Origanum vulgare and Syzygium aromaticum Essential Oils Against Oral Candida albicans

Background Oral candidiasis is the most prevalent oral fungal infection, and existing antifungal agents have side effects such as drug intolerance, resistance, and toxicity. Herbal essential oils are emerging as an alternative therapeutic approach for treating fungal infections. Origanum vulgare (O. vulgare), commonly known as oregano, and Syzygium aromaticum (S. aromaticum), commonly known as clove, are known to have antifungal properties and are effective against fluconazole-resistant strains. A combination of essential oils has a synergistic effect and aids in achieving effective antifungal activity at sufficiently low concentrations, which could lead to reduced side effects and resistance. Aim of the study This study aimed to formulate and develop an herbal antifungal gel containing O. vulgare and S. aromaticum and evaluate its synergistic antifungal efficacy against oral Candida albicans (C. albicans). Methodology Minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) determinations of O. vulgare and S. aromaticum essential oils were performed individually and in combination to assess the antifungal activity against C. albicans. Based on the obtained MIC and MFC of essential oils in combination, an herbal antifungal gel was formulated. Further, to determine the biocompatible nature of the gel, a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed. Results We found that a combination of O. vulgare and S. aromaticum essential oils showed antifungal activity at a lesser concentration, with a MIC of 0.19 μl/ml and MFC of 0.39 μl/ml when compared to their individual concentrations. Based on our results, an antifungal herbal gel comprising a concentration of 0.6 μl/ml of both essential oils was developed to achieve synergistic antifungal activity against oral C. albicans. The MTT assay of the herbal gel did not show any cytotoxicity. Conclusion The novel herbal antifungal gel containing O. vulgare and S. aromaticum is biocompatible in nature and provides an alternative therapeutic approach for treating oral candidiasis.

Combined in vitro/in silico approaches, molecular dynamics simulations and safety assessment of the multifunctional properties of thymol and carvacrol: A comparative insight

Bioactive compounds derived from medicinal plants have acquired immense attentiveness in drug discovery and development. The present study investigated in vitro and predicted in silico the antibacterial, antifungal, and antiviral properties of thymol and carvacrol, and assessed their safety. The performed microbiological assays against Pseudomonas aeruginosa, Escherichia coli, Salmonella enterica Typhimurium revealed that the minimal inhibitory concentration values ranged from (0.078 to 0.312 mg/mL) and the minimal fungicidal concentration against Candida albicans was 0.625 mg/mL. Molecular docking simulations, stipulated that these compounds could inhibit bacterial replication and transcription functions by targeting DNA and RNA polymerases receptors with docking scores varying between (-5.1 to -6.9 kcal/mol). Studied hydroxylated monoterpenes could hinder C. albicans growth by impeding lanosterol 14α-demethylase enzyme and showed a (ΔG=-6.2 and -6.3 kcal/mol). Computational studies revealed that thymol and carvacrol could target the SARS-Cov-2 spike protein of the Omicron variant RBD domain. Molecular dynamics simulations disclosed that these compounds have a stable dynamic behavior over 100 ns as compared to remdesivir. Chemo-computational toxicity prediction using Protox II webserver indicated that thymol and carvacrol could be safely and effectively used as drug candidates to tackle bacterial, fungal, and viral infections as compared to chemical medication.

Attenuation of NLRP3 Inflammasome by Cigarette Smoke is Correlated with Decreased Defense Response of Oral Epithelial Cells to Candida albicans

BACKGROUND

It is well recognized that both smoke and Candida infection are crucial risk factors for oral mucosal diseases. The nucleotide-binding domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome and its downstream effectors, interleukin (IL)-1β and IL-18, are pivotal to the host defense against Candida and other pathogens.

METHODS

The present study was designed to explore the effects of cigarette smoke and C. albicans on the NLRP3 inflammasome and its downstream signal pathway via in vitro cell model. Oral epithelial cells (Leuk-1 cells) were exposed to cigarette smoke extract (CSE) for 3 days and/or challenged with C. albicans.

RESULTS

Microscopically, Leuk-1 cells exerted a defense response to C. albicans by markedly limiting the formation of germ tubes and microcolonies. CSE clearly eliminated the defense response of Leuk-1 cells. Functionally, CSE repressed NLRP3 inflammasome, and IL-1β and IL-18 activation induced by C. albicans in Leuk-1 cells.

CONCLUSION

Our results suggested that in oral epithelial cells, the NLRP3 inflammasome might be one of the target pathways by which CSE attenuates innate immunity and leads to oral disorders.

Antifungal, Antimycobacterial, Protease and α‒Amylase Inhibitory Activities of a Novel Serine Bifunctional Protease Inhibitor from Adenanthera pavonina L. Seeds

Antifungal resistance poses a significant challenge to disease management, necessitating the development of novel drugs. Antimicrobial peptides offer potential solutions. This study focused on extraction and characterization of peptides from Adenanthera pavonina seeds with activity against Candida species, Mycobacterium tuberculosis, proteases, and α-amylases. Peptides were extracted in phosphate buffer and heated at 90°C for 10 min to create a peptide rich heated fraction (PRHF). After confirming antimicrobial activity and the presence of peptides, the PRHF underwent ion exchange chromatography, yielding retained and non-retained fractions. These fractions were evaluated for antimicrobial activity and cytotoxicity against murine macrophages. The least toxic and most active fraction underwent reversed-phase chromatography, resulting in ten fractions. These fractions were tested for peptides and antimicrobial activity. The most active fraction was rechromatographed on a reversed-phase column, resulting in two fractions that were assessed for antimicrobial activity. The most active fraction revealed a single band of approximately 6 kDa and was tested for inhibitory effects on proteases and α-amylases. Thermal stability experiments were conducted on the 6 kDa peptide at different temperatures followed by reassessment of antifungal activity and circular dichroism. The 6 kDa peptide inhibited yeasts, M. tuberculosis, human salivary and Tenebrio molitor larvae intestine α-amylases, and proteolytic activity from fungal extracts, and thus named ApPI. Remarkably, ApPI retained antifungal activity and conformation after heating and is primarily composed of α-helices. ApPI is a thermally stable serine protease/α-amylase inhibitor from A. pavonina seeds, offering promise as a foundational molecule for innovative therapeutic agents against fungal infections and tuberculosis.

Carvacrol-Induced Vacuole Dysfunction and Morphological Consequences in Nakaseomyces glabratus and Candida albicans

With the prevalence of systemic fungal infections caused by Candida albicans and non-albicans species and their resistance to classical antifungals, there is an urgent need to explore alternatives. Herein, we evaluate the impact of the monoterpene carvacrol, a major component of oregano and thyme oils, on clinical and laboratory strains of C. albicans and Nakaseomyces glabratus. Carvacrol induces a wide range of antifungal effects, including the inhibition of growth and hyphal and biofilm formation. Using biochemical and microscopic approaches, we elucidate carvacrol-induced hyphal inhibition. The significantly reduced survival rates following exposure to carvacrol were accompanied by dose-dependent vacuolar acidification, disrupted membrane integrity, and aberrant morphology. Germ tube assays, used to elucidate the relationship between vacuolar dysfunction and hyphal inhibition, showed that carvacrol significantly reduced hyphal formation, which was accompanied by a defective C. albicans morphology. Thus, we show a link between vacuolar acidification/disrupted vacuole membrane integrity and compromised candidal morphology/morphogenesis, demonstrating that carvacrol exerts its anti-hyphal activity by altering vacuole integrity.

Biofilm Inhibition of Inula viscosa (L.) Aiton and Globularia alypum L. Extracts Against Candida Infectious Pathogens and In Vivo Action on Galleria mellonella Model

The increasing importance of fungal infections has fueled the search for new beneficial alternatives substance from plant extracts. The current study investigates the antifungal and antibiofilm activity of Inula viscosa (L.) Aiton and Globularia alypum (L.) leaves extracts against Candida both in vitro and in vivo. The inhibition of planktonic and sessile Candida albicans and Candida glabrata growth using both leaf extracts are evaluated. Moreover; an in vivo infection model using Galleria mellonella larvae; infected and treated with the extracts are performed. All extracts show fungicidal activity; with a minimum fungicidal concentration (MFC) ranging from 128 to 512 µg mL-1 against the two selected strains of Candida. In particular, the best results are obtained with methanolic extract of I. viscosa and G. alypum with an MFC value of 128 µg mL-1 . The extracts are capable to prevent 90% of biofilm development at minor concentrations ranging from 100.71 ± 2.49 µg mL-1 to 380.4 ± 0.92 µg mL-1 . In vivo, tests on Galleria mellonella larvae show that the extracts increase the survival of the larvae infected with Candida. The attained results reveal that I. viscosa and G. alypum extracts may be considered as new antifungal agents and biofilm inhibiting agents for the pharmaceutical and agro-food field.

Antifungal Biofilm Inhibitory Effects of Combinations of Diclofenac and Essential Oils

Systemic fungal infections have risen in recent decades and most of them are caused by Candida species, which are becoming increasingly resistant to conventional antifungal drugs. Biofilm production has been considered the most common growth form of Candida cells and is associated with a high level of antifungal resistance. At present, international research reports on the antifungal activity of non-traditional antimicrobial drugs and their potential use against life-threatening resistant fungal infections. Indeed, drug repurposing has led to the consideration of well-known compounds as a last-line therapy. The goal of this work is to evaluate the potential synergistic antifungal biofilm activity of new combinations between diclofenac sodium salt (DSS), a widely used non-steroidal anti-inflammatory drug (NSAID), with the essential oils (EOs) of Mentha piperita, Pelargonium graveolens, and Melaleuca alternifolia, whose antifungal activity has been well documented over the years. The in vitro antifungal activity of DSS and EOs was determined on different Candida strains. Susceptibility testing and the synergism of DSS and EOs versus biofilm cells was performed by using the broth microdilution assay and checkerboard methods. Minimum inhibitory concentrations (sMIC50) of DSS alone ranged from 1.25 to 2.05 mg/mL for all the strains considered. These values significantly decreased when the drug was used in combination with the EOs. The fractional inhibitory concentration index (FICI) was lower than 0.5 for almost all the associations, thus indicating a significant synergism, particularly for the DSS-Pelargonium graveolens combination towards the Candida strains examined. These preliminary results show that the combination of the EOs with DSS improves the antifungal activity on all the tested Candida strains, significantly lowering the concentrations of the components used and thus allowing any toxic effects to be overcome.

Antifungal Constituents of Piper crocatum and Their Activities as Ergosterol Biosynthesis Inhibitors Discovered via In Silico Study Using ADMET and Drug-Likeness Analysis

Along with the increasing resistance of Candida spp. to some antibiotics, it is necessary to find new antifungal drugs, one of which is from the medicinal plant Red Betel (Piper crocatum). The purpose of this research is to isolate antifungal constituents from P. crocatum and evaluate their activities as ergosterol biosynthesis inhibitors via an in silico study of ADMET and drug-likeness analysis. Two new active compounds 1 and 2 and a known compound 3 were isolated, and their structures were determined using spectroscopic methods, while their bioactivities were evaluated via in vitro and in silico studies, respectively. Antifungal compound 3 was the most active compared to 1 and 2 with zone inhibition values of 14.5, 11.9, and 13.0 mm, respectively, at a concentration of 10% w/v, together with MIC/MFC at 0.31/1.2% w/v. Further in silico study demonstrated that compound 3 had a stronger ΔG than the positive control and compounds 1 and 2 with -11.14, -12.78, -12.00, and -6.89 Kcal/mol against ERG1, ERG2, ERG11, and ERG24, respectively, and also that 3 had the best Ki with 6.8 × 10-3, 4 × 10-4, 1.6 × 10-3, and 8.88 μM. On the other hand, an ADMET analysis of 1-3 met five parameters, while 1 had one violation of Ro5. Based on the research data, the promising antifungal constituents of P. crocatum allow P. crocatum to be proposed as a new antifungal candidate to treat and cure infections due to C. albicans.

Structural and Functional Alterations Caused by Aureobasidin A in Clinical Resistant Strains of Candida spp

Candida species are one of the most concerning causative agents of fungal infections in humans. The treatment of invasive Candida infections is based on the use of fluconazole, but the emergence of resistant isolates has been an increasing concern which has led to the study of alternative drugs with antifungal activity. Sphingolipids have been considered a promising target due to their roles in fungal growth and virulence. Inhibitors of the sphingolipid biosynthetic pathway have been described to display antifungal properties, such as myriocin and aureobasidin A, which are active against resistant Candida isolates. In the present study, aureobasidin A did not display antibiofilm activity nor synergism with amphotericin B, but its combination with fluconazole was effective against Candida biofilms and protected the host in an in vivo infection model. Alterations in treated cells revealed increased oxidative stress, reduced mitochondrial membrane potential and chitin content, as well as altered morphology, enhanced DNA leakage and a greater susceptibility to sodium dodecyl sulphate (SDS). In addition, it seems to inhibit the efflux pump CaCdr2p. All these data contribute to elucidating the role of aureobasidin A on fungal cells, especially evidencing its promising use in clinical resistant isolates of Candida species.

In vitro activity of sanitizers against mono- and polymicrobial biofilms of C. parapsilosis and S. aureus

The emergence of disinfectant-resistant microorganisms poses a significant threat to public health. These resilient pathogens can survive and thrive in hospital settings despite routine disinfection practices, leading to persistent infections and the potential for outbreaks. In this study, we investigated the impact of 11 different commercial sanitizers at various concentrations and exposure times on biofilms consisting of clinical and nosocomial environmental isolates of Candida parapsilosis and Staphylococcus aureus. Among the sanitizers tested, 0.5% and 2.0% chlorhexidine (CLX), 10% polyvinyl pyrrolidone (PVP-I), a disinfectant based on quaternary ammonium compound (QAC), 2% glutaraldehyde, and 0.55% orthophthalaldehyde (OPA) demonstrated efficacy against both C. parapsilosis and S. aureus in monospecies and mixed biofilms. Analysis showed that 0.5% CLX and 10% PVP-I had fungicidal and bactericidal activity against all biofilms. However, the sanitizer based on QAC and 0.55% OPA proved to be bacteriostatic and fungicidal against both monospecies and mixed biofilms. In mixed biofilms, despite the last four sanitizers exerting fungicidal action, the reduction of fungal cells was approximately 4 log10 CFU/mL compared to monospecies biofilms, showing that the interaction provided more resistance of the yeast to the sanitizer. Formation of mixed biofilms in hospital settings can create an ecological niche that enhances the survival of pathogens against routine sanitization procedures. Therefore, effective sanitization practices, including regular cleaning with effective sanitizers, should be implemented to prevent C. parapsilosis/S. aureus biofilm formation in healthcare settings.

Synthesis and Antifungal Evaluation of New Azole Derivatives against Candida albicans

In this study, we designed and prepared a series of new azole derivatives by recombination of fluconazole (FLC) and ketoconazole units, and in vitro antifungal activities against Candida albicans were evaluated. The results indicated that most azoles showed good antifungal activity against the drug-sensitive C. albicans strain, especially compounds 6a, 6e, 6n, 6p, 6r, 6s, 6t, and 6v, which displayed better antifungal activity (MIC50 < 1.0 μg/mL) than FLC against SC5314. The further mechanism study showed that compound 6r could significantly inhibit the formation of C. albicans biofilm, increase the permeability of the cell membrane, reduce the ergosterol level of the cell membrane, damage the membrane structure, and destroy the integrity of the cell structure to exert excellent antifungal activity. Subsequently, a molecular docking study indicated that azole compounds could inhibit cytochrome P450 14α-demethylase (CYP51). Therefore, these azole derivatives can be considered as potent antifungal drugs to treat fungal infections.

K-aurein: A notable aurein 1.2-derived peptide that modulates Candida albicans filamentation and reduces biofilm biomass

Candida albicans is considered one of the most important opportunistic fungi due to the large arsenal of virulence factors that help throughout the progress of the infection. In this sense, antimicrobial peptides (AMPs) appear as an alternative, with great antifungal action. Among these, aurein 1.2 has been widely explored, becoming the basis for the discovery of new AMPs, such as K-aurein (K-au). Thus, this study evaluated the anti-C. albicans potential of K-au against virulence factors, planktonic growth, and biofilm formation of clinical isolates. Firstly, K-au antifungal activity was determined by the microdilution method and time-kill curve. The inhibition of hydrolytic enzyme secretion (proteinase, phospholipase, and hemolysin) and germ tube formation was tested. Then, the antibiofilm potential of K-au was verified through biomass quantification and scanning electron microscopy (SEM). All tests were compared with the classical antifungal drug, amphotericin B (AmB). The outcomes showed fungicidal action of K-au at 62.50 µg mL-1 for all isolates, with a time of action around 150-180 min, determined by the time-kill curve. K-au-treated cells decreased by around 40% of the germinative tube compared to the control. Additionally, K-au inhibited the biofilm formation by more than 90% compared to AmB and the control group. SEM images show apparent cellular disaggregation without the formation of filamentous structures. Therefore, the findings suggest a promising anti-C. albicans effect of K-au due to its fungicidal activity against planktonic cells, or its ability to inhibit important virulence factors like germ tube and biofilm formation. Thus, this peptide could be explored as a useful compound against C. albicans-related infection.

Cyclometalated iridium(III) complexes combined with fluconazole: antifungal activity against resistant C. albicans

Candida albicans (C. albicans) is a ubiquitous clinical fungal pathogen. In recent years, combination therapy, a potential treatment method to overcome C. albicans resistance, has gained traction. In this study, we synthesized a series of cyclometalated iridium(III) complexes with the formula [Ir(C-N)2(tpphz)](PF6) (C-N = 2-phenylpyridine (ppy, in Ir1), 2-(2-thienyl)pyridine (thpy, in Ir2), 2-(2,4-difluorophenyl) pyridine (dfppy, in Ir3), tpphz = tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]phenazine) and polypyridyl ruthenium(II) complexes with the formula [Ru(N-N)2(tpphz)](PF6)2 (N-N = 2,2'-bipyridine (bpy, in Ru1), 1,10-phenanthroline (phen, in Ru2), 4,7-diphenyl-1,10-phenanthroline (DIP, in Ru3)), and investigated their antifungal activities against drug-resistant C. albicans and their combination with fluconazole (FLC). Of which, the combination of the lead iridium(III) complex Ir2 and FLC showed strong antifungal activity against drug-resistant C. albicans. Mechanism studies have shown that they can inhibit the formation of hyphae and biofilm, damage mitochondrial function and accumulate intracellular ROS. Therefore, iridium(III) complexes combined with FLC can be used as a promising treatment to exert anti-drug-resistant C. albicans activity, in order to improve the treatment efficiency of fungal infection.

In-vitro evaluation of virulence markers and antifungal resistance of clinical Candida albicans strains isolated from Karachi, Pakistan

Candidiasis is a significant fungal infection with high mortality and morbidity rates worldwide. Candida albicans is the most dominant species responsible for causing different manifestations of candidiasis. Certain virulence traits as well as its resistance to antifungal drugs contribute to the pathogenesis of this yeast. This study was designed to determine the production of some virulence factors, such as biofilm formation and extracellular hydrolytic enzymes (esterase, coagulase, gelatinase, and catalase) by this fungus, as well as its antifungal resistance profile. A total of 304 clinical C. albicans isolates obtained from different clinical specimens were identified by a conventional diagnostic protocol. The antifungal susceptibility of C. albicans strains was determined by disk diffusion technique against commercially available antifungal disks, such as nystatin 50 μg, amphotericin B 100 unit, fluconazole 25 μg, itraconazole 10 μg, ketoconazole 10 μg, and voriconazole 1 μg. The assessment of biofilm formation was determined by the tube staining assay and spectrophotometry. Gelatinase, coagulase, catalase, and esterase enzyme production was also detected using standard techniques. A total of 66.1% (201/304) and 28.9% (88/304) of C. albicans strains were susceptible-dose dependent (SDD) to nystatin and itraconazole, respectively. Among the antifungal drugs, C. albicans strains showed high resistance to ketoconazole 24.7% (75/304); however, no statistically significant relationship between the clinical origin of C. albicans isolates and antifungal drug resistance pattern was detected. For virulence factors, the majority of the C. albicans strains actively produced biofilm and all hydrolytic enzymes. Biofilm formation was demonstrated by 88% (267/304) of the strains with a quantitative mean value 0.1762 (SD ± 0.08293). However, 100% (304/304) of isolates produced catalase enzyme, 69% (211/304) produced coagulase, 66% (197/304) produced gelatinase, and 52% (157/304) produced esterase enzyme. A significant relationship between the source of specimens and biofilm formation by C. albicans was observed; nevertheless, there was no significant relationship between different sources of C. albicans strains and the production of different enzymatic virulence factors. The study found that C. albicans strains have excellent potential to produce virulence markers and resistance to antifungals, which necessitates surveillance of these opportunistic pathogens to minimize the chances of severe invasive infections.

Cinnamaldehyde Loaded Poly(lactide-co-glycolide) (PLGA) Microparticles for Antifungal Delivery Application against Resistant Candida albicans and Candida glabrata

Researchers have explored natural products to combat the antibiotic resistance of various microorganisms. Cinnamaldehyde (CIN), a major component of cinnamon essential oil (CC-EO), has been found to effectively inhibit the growth of bacteria, fungi, and mildew, as well as their production of toxins. Therefore, this study aimed to create a delivery system for CIN using PLGA microparticles (CIN-MPs), and to compare the antifungal activity of the carried and free CIN, particularly against antibiotic-resistant strains of Candida spp. The first part of the study focused on synthesizing and characterizing the PLGA MPs, which had no toxic effects in vivo and produced results in line with the existing literature. The subsequent experiments analyzed the antifungal effects of MPs-CIN on Candida albicans and Candida glabrata, both resistant (R) and sensitive (S) strains and compared its efficacy with the conventional addition of free CIN to the culture medium. The results indicated that conveyed CIN increased the antifungal effects of the product, particularly towards C. albicans R. The slow and prolonged release of CIN from the PLGA MPs ensured a constant and uniform concentration of the active principle within the cells.

Biosynthesis of cellulose from Ulva lactuca, manufacture of nanocellulose and its application as antimicrobial polymer

Green nanotechnology has recently been recognized as a more proper and safer tool for medical applications thanks to its natural reductions with low toxicity and avoidance of injurious chemicals. The macroalgal biomass was used for nanocellulose biosynthesis. Algae are abundant in the environment and have a high content of cellulose. In our study, we extracted parent cellulose from Ulva lactuca where consecutive treatments extracted cellulose to obtain an insoluble fraction rich in cellulose. The extracted cellulose has the same results obtained by matching it with reference cellulose, especially the same Fourier transform infrared (FTIR) and X-Ray diffraction (XRD) analysis peaks. Nanocellulose was synthesized from extracted cellulose with hydrolysis by sulfuric acid. Nanocellulose was examined by Scanning electron microscope (SEM) shown by a slab-like region as Fig. 4a and Energy dispersive X-ray (EDX) to examine the chemical composition. The size of nanocellulose in the range of 50 nm is calculated by XRD analysis. Antibacterial examination of nanocellulose was tested against Gram+ bacteria like Staphylococcus aureus (ATCC6538), Klebsiella pneumonia (ST627), and Gram-negative bacteria such as Escherichia coli (ATCC25922), and coagulase-negative Staphylococci (CoNS) to give 4.06, 4.66, 4.93 and 4.43 cm as respectively. Comparing the antibacterial effect of nanocellulose with some antibiotics and estimating minimal Inhibitory Concentration (MIC) of nanocellulose. We tested the influence of cellulose and nanocellulose on some fungi such as Aspergillus flavus, Candida albicans, and Candida tropicalis. These results demonstrate that nanocellulose could be developed as an excellent solution to these challenges, making nanocellulose extracted from natural algae a very important medical material that is compatible with sustainable development.

Benzo[g]quinazolines as antifungal against candidiasis: Screening, molecular docking, and QSAR investigations

Candida albicans, an opportunistic pathogen, is the most common type of fungus and represents a substantial source of human invasive disease (nosocomial infection). This category of fungi are part of our microbiota, and given the appropriate environmental conditions, it has the potential to cause both superficial and systemic infections. There is a soaring resistance against the available anticandidal agents. The purpose of this research is to investigate the activity of certain previously synthesized benzo[g]quinazolines against C. albicans in vitro by using the cup-plate diffusion method. There was a marked difference in the effectiveness of the target compounds 1-6 against the sample of C. albicans that was tested. Benzo[g]quinazolines 1 (inhibition zone = 20 mm) and 2 (inhibition zone = 22 mm) had good effects in comparison to fluconazole (inhibition zone = 26 mm). A docking study was conducted between benzo[g]quinazolines 1-6 and Candida spp. CYP51 to establish the binding mode compared with fluconazole and VT-1161 (oteseconazole) as reference medicines, and it was determined that binding at the active site of Candida spp. CYP51 occurred in the same manner. Quantitative structure-activity relationship (QSAR) investigation was performed to further characterize the identified anticandidal agents and recognize the major regulatory components governing such activity. In future studies, the benzo[g]quinazoline scaffold could serve as a model for the design and development of novel derivatives with antifungal potential.

Evaluation of citrus pectin capped copper sulfide nanoparticles against Candidiasis causing Candida biofilms

The incidence of candidiasis has significantly increased globally in recent decades, and it is a significant source of morbidity and mortality, particularly in critically ill patients. Candida sp. ability to generate biofilms is one of its primary pathogenic traits. Drug-resistant strains have led to clinical failures of traditional antifungals, necessitating the development of a more modern therapy that can inhibit biofilm formation and enhance Candida sp. sensitivity to the immune system. The present study reports the anticandidal potential of pectin-capped copper sulfide nanoparticles (pCuS NPs) against Candida albicans. The pCuS NPs inhibit C. albicans growth at a minimum inhibitory concentration (MIC) of 31.25 μM and exhibit antifungal action by compromising membrane integrity and overproducing reactive oxygen species. The pCuS NPs, at their biofilm inhibitory concentration (BIC) of 15.63 μM, effectively inhibited C. albicans cells adhering to the glass slides, confirmed by light microscopy and scanning electron microscopy. Phase contrast microscopy pictures revealed that NPs controlled the morphological transitions between the yeast and hyphal forms by limiting conditions that led to filamentation and reducing hyphal extension. In addition, C. albicans showed reduced exopolysaccharide (EPS) production and exhibited less cell surface hydrophobicity (CSH) after pCuS NPs treatment. The findings suggest that pCuS NPs may be able to inhibit the emergence of virulence traits that lead to the formation of biofilms, such as EPS, CSH, and hyphal morphogenesis. The results raise the possibility of developing NPs-based therapies for C. albicans infections associated with biofilms.

A first-in-class inhibitor of Hsp110 molecular chaperones of pathogenic fungi

Proteins of the Hsp110 family are molecular chaperones that play important roles in protein homeostasis in eukaryotes. The pathogenic fungus Candida albicans, which causes infections in humans, has a single Hsp110, termed Msi3. Here, we provide proof-of-principle evidence supporting fungal Hsp110s as targets for the development of new antifungal drugs. We identify a pyrazolo[3,4-b] pyridine derivative, termed HLQ2H (or 2H), that inhibits the biochemical and chaperone activities of Msi3, as well as the growth and viability of C. albicans. Moreover, the fungicidal activity of 2H correlates with its inhibition of in vivo protein folding. We propose 2H and related compounds as promising leads for development of new antifungals and as pharmacological tools for the study of the molecular mechanisms and functions of Hsp110s.

The association between <i>Candida albicans</i> sensitivity to antimycotic drugs and the architecture of their microbial community in the oropharynx of HIV infected patients

Relevance. Candida infection remains relevant due to the wide spread of antimycotic-resistant strains of Candida fungi, especially among immunocompromised individuals. It was previously discovered that the Candida spp. microbial community in the biotope of the oropharynx of HIV infected patients is characterized by a certain architecture: they can be present in this biotope in the form of a monoculture or as association of co-isolates. It has been suggested that the architecture of the Candida microbial community may influence their resistance to antimycotic drugs. Purpose a comparative study of the association between the architecture of the C. albicans microbial community in the oropharynx of HIV infected patients with oropharyngeal candidiasis and their sensitivity to antimycotic drugs. Materials and methods. A microbiological study of 52 isolates of Candida fungi (C. albicans, C. glabrata, C. tropicalis and C. krusei) from the oropharynx of 31 HIV infected patients with clinical manifestations of oropharyngeal candidiasis aged 20 to 69 years with almost equal gender distribution was carried out. In the form of monocultures, 18 isolates were isolated, while 34 were identified as co-isolates, which formed 16 homogeneous communities that included strains of the same species, and 18 heterogeneous ones that consisted of fungi of various species. Results. It was found that heterogeneous communities of C. albicans were markedly distinguished by sensitivity to antimycotic drugs, in particular, by low sensitivity to imidazoles. Homogeneous communities practically did not differ from monocultural ones. The general properties of the C. non-albicans population were largely similar to those of C. albicans, but were characterized by lower heterogeneity in response to antimycotic drugs. Conclusion. The architecture of the community of C. albicans isolated from the oropharynx of HIV infected patients with clinical manifestations of oropharyngeal candidiasis affects their sensitivity to antimycotic drugs. When selecting effective antimycotic therapy for such patients, it is necessary to take into account the structure of the Candida spp. community in the oropharynx.

Synthesis and Characterization of Sulfur Nanoparticles of Citrus limon Extract Embedded in Nanohydrogel Formulation: In Vitro and In Vivo Studies

The study aimed to synthesize non-noxious, clean, reliable, and green sulfur nanoparticles (SNPs) from Citrus limon leaves. The synthesized SNPs were used to analyze particle size, zeta potential, UV–visible spectroscopy, SEM, and ATR-FTIR. The prepared SNPs exhibited a globule size of 55.32 ± 2.15 nm, PDI value of 0.365 ± 0.06, and zeta potential of −12.32 ± 0.23 mV. The presence of SNPs was confirmed by UV–visible spectroscopy in the range of 290 nm. The SEM image showed that the particles were spherical with a size of 40 nm. The ATR-FTIR study showed no interaction, and all the major peaks were preserved in the formulations. An antimicrobial and antifungal study of SNPs was carried out against Gram-positive bacteria (Staph. aureus, Bacillus), Gram-negative bacteria (E. coli and Bordetella), and fungal strains (Candida albicans). The study showed that Citrus limon extract SNPs exhibited better antimicrobial and antifungal activities against Staph. aureus, Bacillus, E. coli, Bordetella, and Candida albicans at a minimal inhibitory concentration of 50 μg/mL. Different antibiotics were used alone and in combination with SNPs of Citrus limon extract to evaluate their activity against various strains of bacteria and fungal strains. The study showed that using SNPs of Citrus limon extract with antibiotics has a synergistic effect against Staph.aureus, Bacillus, E. coli, Bordetella, and Candida albicans. SNPs were embedded in nanohydrogel formulations for in vivo (wound healing) studies. In preclinical studies, SNPs of Citrus limon extract embedded within a nanohydrogel formulation (NHGF4) have shown promising results. To be widely used in clinical settings, further studies are needed to evaluate their safety and efficacy in human volunteers.

Candida spp. DNA Extraction in the Age of Molecular Diagnosis

The standard procedure for the detection of candidemia is blood culture, a method that might require 3-5 days for a positive result. Compared with culturing, molecular diagnosis techniques can provide faster diagnosis. The current paper aimed to present the main strengths and constraints of current molecular techniques for Candida spp. DNA extraction, analyzing their efficiency from a time, price, and ease of usage point of view. A comprehensive search was conducted using the PubMed NIH database for peer-reviewed full-text articles published before October 2022. The studies provided adequate data on the diagnosis of the infection with the Candida spp. DNA extraction is a relevant step in yielding pure qualitative DNA to be amplified in molecular diagnostic techniques. The most used fungal DNA extraction strategies are: mechanical (bead beating, ultrasonication, steel-bullet beating), enzymatic (proteinase K, lysozyme, lyticase), and chemical extraction (formic acid, liquid nitrogen, ammonium chloride). More clinical studies are needed to formulate adequate guidelines for fungal DNA extraction as the current paper highlighted discrepancies in the reported outcome.

Chemical Profile, Anti-Microbial and Anti-Inflammaging Activities of Santolina rosmarinifolia L. Essential Oil from Portugal

Fungal infections and the accompanying inflammatory responses are associated with great morbidity and mortality due to the frequent relapses triggered by an increased resistance to antifungal agents. Furthermore, this inflammatory state can be exacerbated during inflammaging and cellular senescence. Essential oils (EO) are receiving increasing interest in the field of drug discovery due to their lipophilic nature and complex composition, making them suitable candidates in the development of new antifungal drugs and modulators of numerous molecular targets. This work chemically characterized the EO from Santolina rosmarinifolia L., collected in Setúbal (Portugal), and assessed its antifungal potential by determining its minimum inhibitory (MIC) and minimum lethal (MLC) concentration in accordance with the Clinical Laboratory Standard Guidelines (CLSI) guidelines, as well as its effect on several Candida albicans virulence factors. The anti-inflammatory effect was unveiled using lipopolysaccharide (LPS)-stimulated macrophages by assessing several pro-inflammatory mediators. The wound healing and anti-senescence potential of the EO was also disclosed. The EO was mainly characterized by β-pinene (29.6%), borneol (16.9%), myrcene (15.4%) and limonene (5.7%). It showed a strong antifungal effect against yeasts and filamentous fungi (MIC = 0.07-0.29 mg/mL). Furthermore, it inhibited dimorphic transition (MIC/16), decreased biofilm formation with a preeminent effect after 24 h (MIC/2) and disrupted preformed biofilms in C. albicans. Additionally, the EO decreased nitric oxide (NO) release (IC₅₀ = 0.52 mg/mL) and pro-IL-1β and inducible nitric oxide synthase (iNOS) expression in LPS-stimulated macrophages, promoted wound healing (91% vs. 81% closed wound) and reduced cellular senescence (53% vs. 73% β-galactosidase-positive cells). Overall, this study highlights the relevant pharmacological properties of S. rosmarinifolia, opening new avenues for its industrial exploitation.

Nanotechnology-Based Approaches for Voriconazole Delivery Applied to Invasive Fungal Infections

Invasive fungal infections increase mortality and morbidity rates worldwide. The treatment of these infections is still limited due to the low bioavailability and toxicity, requiring therapeutic monitoring, especially in the most severe cases. Voriconazole is an azole widely used to treat invasive aspergillosis, other hyaline molds, many dematiaceous molds, Candida spp., including those resistant to fluconazole, and for infections caused by endemic mycoses, in addition to those that occur in the central nervous system. However, despite its broad activity, using voriconazole has limitations related to its non-linear pharmacokinetics, leading to supratherapeutic doses and increased toxicity according to individual polymorphisms during its metabolism. In this sense, nanotechnology-based drug delivery systems have successfully improved the physicochemical and biological aspects of different classes of drugs, including antifungals. In this review, we highlighted recent work that has applied nanotechnology to deliver voriconazole. These systems allowed increased permeation and deposition of voriconazole in target tissues from a controlled and sustained release in different routes of administration such as ocular, pulmonary, oral, topical, and parenteral. Thus, nanotechnology application aiming to delivery voriconazole becomes a more effective and safer therapeutic alternative in the treatment of fungal infections.

Evaluation of the Synthetic Multifunctional Peptide Hp-MAP3 Derivative of Temporin-PTa

In recent years, antimicrobial peptides isolated from amphibian toxins have gained attention as new multifunctional drugs interacting with different molecular targets. We aimed to rationally design a new peptide from temporin-PTa. Hp-MAP3 (NH2-LLKKVLALLKKVL-COOH), net charge (+4), hydrophobicity (0.69), the content of hydrophobic residues (69%), and hydrophobic moment (0.73). For the construction of the analog peptide, the physicochemical characteristics were reorganized into hydrophilic and hydrophobic residues with the addition of lysines and leucines. The minimum inhibitory concentration was 2.7 to 43 μM against the growth of Gram-negative and positive bacteria, and the potential for biofilm eradication was 173.2 μM. Within 20 min, the peptide Hp-MAP3 (10.8 μM) prompted 100% of the damage to E. coli cells. At 43.3 μM, eliminated 100% of S. aureus within 5 min. The effects against yeast species of the Candida genus ranged from 5.4 to 86.6 μM. Hp-MAP3 presents cytotoxic activity against tumor HeLa at a concentration of 21.6 μM with an IC50 of 10.4 µM. Furthermore, the peptide showed hemolytic activity against murine erythrocytes. Structural studies carried out by circular dichroism showed that Hp-MAP3, while in the presence of 50% trifluoroethanol or SDS, an α-helix secondary structure. Finally, Amphipathic Hp-MAP3 building an important model for the design of new multifunctional molecules.

Untargeted metabolomics to evaluate antifungal mechanism: a study of Cophinforma mamane and Candida albicans interaction

Microbial interactions between filamentous fungi and yeast are still not fully understood. To evaluate a potential antifungal activity of a filamentous fungus while highlighting metabolomic changes, co-cultures between an endophytic strain of Cophinforma mamane (CM) and Candida albicans (CA) were performed. The liquid cultures were incubated under static conditions and metabolite alterations during the course were investigated by ultra-performance liquid chromatography-tandem mass spectrophotometry (UPLC-MS/MS). Results were analyzed using MS-DIAL, MS-FINDER, METLIN, Xcalibur, SciFinder, and MetaboAnalyst metabolomics platforms. The metabolites associated with catabolic processes, including the metabolism of branched-chain amino acids, carnitine, and phospholipids were upregulated both in the mono and co-cultures, indicating fungal adaptability to environmental stress. Several metabolites, including C20 sphinganine 1-phosphate, myo-inositol, farnesol, gamma-undecalactone, folinic acid, palmitoleic acid, and MG (12:/0:0/0:0) were not produced by CA during co-culture with CM, demonstrating the antifungal mechanism of CM. Our results highlight the crucial roles of metabolomics studies to provide essential information regarding the antifungal mechanism of C. mamane against C. albicans, especially when the lost/undetected metabolites are involved in fungal survival and pathogenicity.

Vaccine development for pathogenic fungi: current status and future directions

INTRODUCTION

Fungal infections are caused by a broad range of pathogenic fungi that are found worldwide with different geographic distributions, incidences, and mortality rates. Considering that there are relatively few approved medications available for combating fungal diseases and no vaccine formulation commercially available, multiple groups are searching for new antifungal drugs, examining drugs for repurposing and developing antifungal vaccines, in order to control deaths, sequels, and the spread of these complex infections.

AREAS COVERED

This review provides a summary of advances in fungal vaccine studies and the different approaches under development, such as subunit vaccines, whole organism vaccines, and DNA vaccines, as well as studies that optimize the use of adjuvants. We conducted a literature search of the PubMed with terms: fungal vaccines and genus of fungal pathogens (Cryptococcus spp. Candida spp. Coccidioides spp. Aspergillus spp. Sporothrix spp. Histoplasma spp. Paracoccidioides spp. Pneumocystis spp. and the Mucorales order), a total of 177 articles were collected from database.

EXPERT OPINION

Problems regarding the immune response development in an immunocompromised organism, the similarity between fungal and mammalian cells, and the lack of attention by health organizations to fungal infections are closely related to the fact that, at present, there are no fungal vaccines available for clinical use.

Clinical characteristics of central nervous system candidiasis due to Candida albicans in children: a single-center experience

BACKGROUND

Central nervous system candidiasis due to Candida albicans (CNSC) in children is easily misdiagnosed and is associated with poor outcomes and a high mortality rate. There is no big data research or systematic review of CNSC.

METHODS

Patients diagnosed as CNSC with positive culture results of Candida albicans in Beijing Children's Hospital affiliated to Capital Medical University from March 2010 to March 2019 were included. Patients receiving immunosuppressive therapy or transplantation, or with malignant tumours were excluded. We analysed the clinical characteristics, follow-up results, drug susceptibility tests and whole-exome sequencing (WES) results.

RESULTS

Thirty-three definitive patients were enrolled, including 22 males and 11 females. Twenty-five patients suffered from CNSC when they were less than 1 year old, and a total of 29 patients had high-risk factors. The main clinical manifestations were fever, convulsions, and positive neurological signs. Twenty-two patients had CNS infections alone, and 11 patients had CNS infections combined with invasive infections involving multiple sites. Twenty-seven cases had a positive CSF and/or blood culture at our hospital. All strains were susceptible to fluconazole, and 2 strains had intermediate susceptibility to voriconazole. As for amphotericin B, all the strains were wild type (WT). WES of 16 patients revealed 2 cases with CARD9 mutations, who suffered from recurrent onychomycosis or thrush before.

CONCLUSION

CNSC mostly existed in children younger than 1 year old, who all had underlying risk factors. CNSC patients with onset at an older age or with recurrent superficial fungal infections might have primary immunodeficiency.

Sphingosine as a New Antifungal Agent against Candida and Aspergillus spp

This study investigated whether sphingosine is effective as prophylaxis against Aspergillus spp. and Candida spp. In vitro experiments showed that sphingosine is very efficacious against A. fumigatus and Nakeomyces glabrataa (formerly named C. glabrata). A mouse model of invasive aspergillosis showed that sphingosine exerts a prophylactic effect and that sphingosine-treated animals exhibit a strong survival advantage after infection. Furthermore, mechanistic studies showed that treatment with sphingosine leads to the early depolarization of the mitochondrial membrane potential (Δψm) and the generation of mitochondrial reactive oxygen species and to a release of cytochrome C within minutes, thereby presumably initiating apoptosis. Because of its very good tolerability and ease of application, inhaled sphingosine should be further developed as a possible prophylactic agent against pulmonary aspergillosis among severely immunocompromised patients.

Establishment and application of loop-mediated isothermal amplification coupled with nanoparticle-based lateral flow biosensor (LAMP-LFB) for visual and rapid diagnosis of Candida albicans in clinical samples

Candida albicans is an opportunistic pathogenic yeast that predominantly causes invasive candidiasis. Conventional methods for detecting Candida species are costly, take 3-5 days, and require skilled technicians. Rapid pathogen identification is important in managing invasive candidiasis infection. Here, a novel molecular diagnostic assay termed loop-mediated isothermal amplification combined with nanoparticles-based lateral flow biosensor (LAMP-LFB) was developed for C. albicans rapid detection. A set of six primers was designed based on the C. albicans species-specific internal transcribed spacer 2 (ITS2) gene. The C. albicans-LAMP results were visually reported by LFB within 2 min. Various fungal strains representing Candida species, as well as several Gram-negative and Gram-positive bacterial species, were used to determine the analytical sensitivity and specificity of the assay. The optimal LAMP conditions were 64 °C for 40 min, with a sensitivity of 1 fg of genomic DNA template from C. albicans pure cultures. No cross-reactions were obtained with non-albicans strains. Thus, the analytical specificity of the LAMP-LFB assay was 100%. The entire procedure could be completed within 85 min, including specimen processing (40 min), isothermal reaction (40 min), and result reporting (within 2 min). In 330 clinical samples (including 30 whole blood, 100 middle segment urine, and 200 sputum samples), all C. albicans-positive (62/330) samples were identified by LAMP-LFB assay, and the diagnostic accuracy was 100% when compared to the traditional clinical cultural-based methods. Thus, this assay can be used as a diagnostic tool for the rapid, accurate, sensitive, low-cost and specific detection of C. albicans strains, especially in resource-limited settings.

Autophagy regulation of ATG13 and ATG27 on biofilm formation and antifungal resistance in Candida albicans

Autophagy is a highly conserved catabolic pathway that is vital for cells; however, the effects of autophagy on the biofilm formation and antifungal resistance of Candida albicans are still unknown. In this study, the potential molecular mechanisms of autophagy in biofilm formation and antifungal resistance were investigated. It was found that 3536 genes were differentially expressed between biofilm and planktonic C. albicans. ATG gene expression and autophagy activity were higher in biofilm than in planktonic C. albicans. Autophagic activities were higher in matured biofilms than that in pre-matured biofilms. Autophagy was involved in C. albicans biofilm formation and its activity increased during biofilm maturation. Further, ALP activity, AO staining cells, and autophagosomes inside cells were obviously reduced in biofilms of atg13Δ/Δ and atg27Δ/Δ strains; moreover, biofilm formation and antifungal resistance were also significantly decreased. Lastly, autophagy regulates biofilm formation and drug resistance of C. albicans and could be served as a new molecular target to the C. albicans biofilm infections.

Bioactive compounds with antifungal activity against pathogens isolated from pregnant woman: Gallesia integrifolia (garlic wood) is a promising treatment for vulvovaginal candidiasis

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves, bark, and roots of Gallesia integrifolia are consumed in folk medicine through infusion, decoction, and topical preparation by crushing because of its pharmacological properties in several peripheral system disorders, including microbial infections. The presence of various molecules in different parts of the plant likely confers this species' fungicidal action, but scientific evidence is lacking. Vulvovaginal candidiasis mainly affects women of reproductive age. When left untreated, it can cause pregnancy complications. Currently available antifungals often cause undesirable side effects. New alternative therapeutic strategies based on medicinal plants have been proposed.

AIM

To investigate the antifungal activity of G. integrifolia against vulvovaginal candidiasis secretion in pregnant women.

MATERIALS AND METHODS

Antifungal activity was determined by the minimum inhibitory concentration (MIC), determined by broth microdilution method using Candida spp (NEWP1210), C. albicans (CCCD-CC001), C. tropicalis (CCCD-CC002) standard and clinical isolates from pregnant women with vulvovaginal candidiasis. Nystatin and fluconazole were used as positive controls. The chemical composition of essential oils that were extracted from leaves, flowers, and fruits of G. integrifolia was determined by gas chromatography coupled to mass spectrometry. Reverse docking was used to suggest a possible target in Candida. Conventional docking was used to identify the most probable compound that inhibits fungal growth.

RESULTS

A total of 24 compounds were identified, accounting for ∼99% of volatile constituents in the essential oils. Leaves of G. integrifolia contained 3,5-dithiahexanol-5,5-dioxide (40.93%), flowers contained methionine ethyl ester (46.78%), and fruits contained 2,8-dithianonane (54.01%) as the most abundant compounds. The MICs of essential oils of leaves, flowers, and fruits of G. integrifolia against standard strains of Candida spp, C. albicans, and C. tropicalis ranged from 13.01 to 625.00 μg/mL. The essential oil of flowers more effectively inhibited Candida spp. Essential oils of leaves and flowers were similar to fluconazole against C. albicans. Essential oils of flowers and fruits were similar to fluconazole against C. tropocalis. In Candida yeast species that were isolated from vaginal secretion samples from pregnant patients, the MICs of leaves and flowers ranged from 52.08 to 5000.00 μg/mL. The essential oil of leaves (277.77 μg/mL) was the most active against C. albicans. No significant differences were found between the essential oils of leaves and flowers against C. glabrata. Docking simulations suggested that phytol in leaves and flowers was responsible for the antimicrobial effect.

CONCLUSION

The present results suggest the potential therapeutic use of G. integrifolia, especially its leaves and flowers, against Candida and vulvovaginal candidiasis.

Prevalence and Antifungal Susceptibility of Clinically Relevant Candida Species, Identification of Candida auris and Kodamaea ohmeri in Bangladesh

Candida species are major fungal pathogens in humans. The aim of this study was to determine the prevalence of individual Candida species and their susceptibility to antifungal drugs among clinical isolates in a tertiary care hospital in Bangladesh. During a 10-month period in 2021, high vaginal swabs (HVSs), blood, and aural swabs were collected from 360 patients. From these specimens, Candida spp. was isolated from cultures on Sabouraud dextrose agar media, and phenotypic and genetic analyses were performed. A total of 109 isolates were recovered, and C. albicans accounted for 37%, being derived mostly from HVSs. Among non-albicans Candida (NAC), C. parapsilosis was the most frequent, followed by C. ciferrii, C. tropicalis, and C. glabrata. Three isolates from blood and two isolates from aural discharge were genetically identified as C. auris and Kodamaea ohmeri, respectively. NAC isolates were more resistant to fluconazole (overall rate, 29%) than C. albicans (10%). Candida isolates from blood showed 95% susceptibility to voriconazole and less susceptibility to fluconazole (67%). Two or three amino acid substitutions were detected in the ERG11 of two fluconazole-resistant C. albicans isolates. The present study is the first to reveal the prevalence of Candida species and their antifungal susceptibility in Bangladesh.

Repurposing of MitoTam: Novel Anti-Cancer Drug Candidate Exhibits Potent Activity against Major Protozoan and Fungal Pathogens

Many of the currently available anti-parasitic and anti-fungal frontline drugs have severe limitations, including adverse side effects, complex administration, and increasing occurrence of resistance. The discovery and development of new therapeutic agents is a costly and lengthy process. Therefore, repurposing drugs with already established clinical application offers an attractive, fast-track approach for novel treatment options. In this study, we show that the anti-cancer drug candidate MitoTam, a mitochondria-targeted analog of tamoxifen, efficiently eliminates a wide range of evolutionarily distinct pathogens in vitro, including pathogenic fungi, Plasmodium falciparum, and several species of trypanosomatid parasites, causative agents of debilitating neglected tropical diseases. MitoTam treatment was also effective in vivo and significantly reduced parasitemia of two medically important parasites, Leishmania mexicana and Trypanosoma brucei, in their respective animal infection models. Functional analysis in the bloodstream form of T. brucei showed that MitoTam rapidly altered mitochondrial functions, particularly affecting cellular respiration, lowering ATP levels, and dissipating mitochondrial membrane potential. Our data suggest that the mode of action of MitoTam involves disruption of the inner mitochondrial membrane, leading to rapid organelle depolarization and cell death. Altogether, MitoTam is an excellent candidate drug against several important pathogens, for which there are no efficient therapies and for which drug development is not a priority.