Invasive candidiasis

Coincidence of antibodies against Hwp1 and ASCA, two distinct molecular targets of Candida albicans, reinforces the link between this fungal species and coeliac disease

Candida albicans is an immunogen for anti-Saccharomyces cerevisiae antibodies (ASCA), a serological marker of Crohn's disease. ASCA has also been reported in other autoimmune diseases, including coeliac disease (CeD). A strong antibody response against Hwp1, a protein associated with invasive hyphal form of C. albicans which presents peptide sequence homologies with gliadin, has also been described in CeD. This observation supports the hypothesis that C. albicans hyphal transition in C. albicans may trigger CeD onset through a mechanism of molecular/antigenic mimicry. In this study, we assessed whether the anti-C. albicans oligomannose and anti-Hwp1 protein responses may be linked despite their different pathophysiological significance. The measurement of ASCA levels in a cohort of patients involved in our previous Hwp1 study showed a significant correlation between the two biomarkers. This new observation further reinforces the link between C. albicans and CeD.

Emergence of infectious diseases and role of advanced nanomaterials in point-of-care diagnostics: a review

Infectious outbreaks are the foremost global public health concern, challenging the current healthcare system, which claims millions of lives annually. The most crucial way to control an infectious outbreak is by early detection through point-of-care (POC) diagnostics. POC diagnostics are highly advantageous owing to the prompt diagnosis, which is economical, simple and highly efficient with remote access capabilities. In particular, utilization of nanomaterials to architect POC devices has enabled highly integrated and portable (compact) devices with enhanced efficiency. As such, this review will detail the factors influencing the emergence of infectious diseases and methods for fast and accurate detection, thus elucidating the underlying factors of these infections. Furthermore, it comprehensively highlights the importance of different nanomaterials in POCs to detect nucleic acid, whole pathogens, proteins and antibody detection systems. Finally, we summarize findings reported on nanomaterials based on advanced POCs such as lab-on-chip, lab-on-disc-devices, point-of-action and hospital-on-chip. To this end, we discuss the challenges, potential solutions, prospects of integrating internet-of-things, artificial intelligence, 5G communications and data clouding to achieve intelligent POCs.

The pathobiology of human fungal infections

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

Development and evaluation of a loop-mediated isothermal amplification (LAMP) method for Candida glabrata detection

PURPOSE

Loop-mediated isothermal amplification (LAMP) is a simple and rapid nucleic acid method for DNA amplification at a constant temperature. The "gold standard" culture method for yeast detection, has low sensitivity with severe consequences, increasing morbidity and mortality rates. Here, we report the development of a LAMP method for the specific detection of C. glabrata.

METHODOLOGY

The specific LAMP primers for C. glabrata detection were designed and evaluated.

RESULTS

The LAMP assay accurately detected C. glabrata with no cross-reactivity with other Candida species.

CONCLUSION

The developed molecular method would be a promising tool in the management of invasive candidiasis.

Most azole resistance mutations in the Candida albicans drug target confer cross-resistance without intrinsic fitness cost

Azole antifungals are the main drugs used to treat fungal infections. Amino acid substitutions in the drug target Erg11 (Cyp51) are a common resistance mechanism in pathogenic yeasts. How many and which mutations confer resistance is, however, largely unknown. Here we measure the impact of nearly 4,000 amino acid variants of Candida albicans Erg11 on the susceptibility to six clinical azoles. This was achieved by deep mutational scanning of CaErg11 expressed in Saccharomyces cerevisiae. We find that a large fraction of mutations lead to resistance (33%), most resistance mutations confer cross-resistance (88%) and only a handful of resistance mutations show a significant fitness cost (9%). Our results reveal that resistance to azoles can arise through a large set of mutations and this will probably lead to azole pan-resistance, with little evolutionary compromise. This resource will help inform treatment choices in clinical settings and guide the development of new drugs.

Rezafungin versus caspofungin for patients with candidaemia or invasive candidiasis in the intensive care unit: pooled analyses of the ReSTORE and STRIVE randomised trials

BACKGROUND

Rezafungin is an echinocandin approved in the US and EU to treat candidaemia and/or invasive candidiasis. This post-hoc, pooled analysis of the Phase 2 STRIVE and Phase 3 ReSTORE trials assessed rezafungin versus caspofungin in patients with candidaemia and/or invasive candidiasis (IC) in the intensive care unit (ICU) at randomisation.

METHODS

STRIVE and ReSTORE were randomised double-blind trials in adults with systemic signs and mycological confirmation of candidaemia and/or IC in blood or a normally sterile site ≤ 96 h before randomisation. Data were pooled for patients in the ICU at randomisation who received intravenous rezafungin (400 mg loading dose then 200 mg once weekly) or caspofungin (70 mg loading dose then 50 mg once daily) for ≤ 4 weeks. Outcomes were Day 30 all-cause mortality (primary outcome), Day 5 and 14 mycological eradication, time to negative blood culture, mortality attributable to candidaemia/invasive candidiasis, safety, and pharmacokinetics.

RESULTS

Of 294 patients in STRIVE/ReSTORE, 113 were in the ICU at randomisation (rezafungin n = 46; caspofungin n = 67). At baseline, ~ 30% of patients in each group had impaired renal function and/or an Acute Physiologic Assessment and Chronic Health Evaluation II score ≥ 20. One patient (in the caspofungin group) was neutropenic at baseline. Day 30 all-cause mortality was 34.8% for rezafungin versus 25.4% for caspofungin. Day 5 and 14 mycological eradication was 78.3% and 71.7% for rezafungin versus 59.7% and 65.7% for caspofungin, respectively. Median time to negative blood culture was 18 (interquartile range, 12.6-43.0) versus 38 (interquartile range, 15.9-211.3) h for rezafungin versus caspofungin (stratified log-rank P = 0.001; nominal, not adjusted for multiplicity). Candidaemia/IC-attributable deaths occurred in two rezafungin patients versus one caspofungin patient. Safety profiles were similar between groups. Overall, 17.4% (rezafungin) versus 29.9% (caspofungin) of patients discontinued due to treatment-emergent adverse events. Rezafungin exposure following the initial 400-mg dose was comparable between patients in the ICU at randomisation (n = 50) and non-ICU patients (n = 117).

CONCLUSIONS

Rezafungin was well tolerated and efficacious in critically ill, mainly non-neutropenic patients with candidaemia and/or IC. This analysis provides additional insights into the efficacy and safety of rezafungin in the ICU population.

Candida glabrata maintains two HAP1 ohnologs, HAP1A and HAP1B, for distinct roles in ergosterol gene regulation to mediate sterol homeostasis under azole and hypoxic conditions

Candida glabrata exhibits innate resistance to azole antifungal drugs but also has the propensity to rapidly develop clinical drug resistance. Azole drugs, which target Erg11, is one of the major classes of antifungals used to treat Candida infections. Despite their widespread use, the mechanism controlling azole-induced ERG gene expression and drug resistance in C. glabrata has primarily revolved around Upc2 and/or Pdr1. Phylogenetic and syntenic analyses revealed that C. glabrata, following a whole genome duplication event, maintained HAP1A and HAP1B, whereas Saccharomyces cerevisiae only retained the HAP1A ortholog, HAP1. In this study, we determined the function of two zinc cluster transcription factors, Hap1A and Hap1B, as direct regulators of ERG genes. In S. cerevisiae, Hap1, an ortholog of Hap1A, is a known transcription factor controlling ERG gene expression under aerobic and hypoxic conditions. Interestingly, deleting HAP1 or HAP1B in either S. cerevisiae or C. glabrata, respectively, showed altered susceptibility to azoles. In contrast, the strain deleted for HAP1A did not exhibit azole susceptibility. We also determined that the increased azole susceptibility in a hap1BΔ strain is attributed to decreased azole-induced expression of ERG genes, resulting in decreased levels of total ergosterol. Surprisingly, Hap1A protein expression is barely detected under aerobic conditions but is specifically induced under hypoxic conditions, where Hap1A is required for the repression of ERG genes. However, in the absence of Hap1A, Hap1B can compensate as a transcriptional repressor. Our study shows that Hap1A and Hap1B is utilized by C. glabrata to adapt to specific host and environmental conditions.

IMPORTANCE

Invasive and drug-resistant fungal infections pose a significant public health concern. Candida glabrata, a human fungal pathogen, is often difficult to treat due to its intrinsic resistance to azole antifungal drugs and its capacity to develop clinical drug resistance. Therefore, understanding the pathways that facilitate fungal growth and environmental adaptation may lead to novel drug targets and/or more efficacious antifungal therapies. While the mechanisms of azole resistance in Candida species have been extensively studied, the roles of zinc cluster transcription factors, such as Hap1A and Hap1B, in C. glabrata have remained largely unexplored until now. Our research shows that these factors play distinct yet crucial roles in regulating ergosterol homeostasis under azole drug treatment and oxygen-limiting growth conditions. These findings offer new insights into how this pathogen adapts to different environmental conditions and enhances our understanding of factors that alter drug susceptibility and/or resistance.

Anti-fungal peptides: an emerging category with enthralling therapeutic prospects in the treatment of candidiasis

Candida infections, particularly invasive candidiasis, pose a serious global health threat. Candida albicans is the most prevalent species causing candidiasis, and resistance to key antifungal drugs, such as azoles, echinocandins, polyenes, and fluoropyrimidines, has emerged. This growing multidrug resistance (MDR) complicates treatment options, highlighting the need for novel therapeutic approaches. Antifungal peptides (AFPs) are gaining recognition for their potential as new antifungal agents due to their diverse structures and functions. These natural or recombinant peptides can effectively target fungal virulence and viability, making them promising candidates for future antifungal development. This review examines infections caused by Candida species, the limitations of current antifungal treatments, and the therapeutic potential of AFPs. It emphasizes the importance of identifying novel AFP targets and their production for advancing treatment strategies. By discussing the therapeutic development of AFPs, the review aims to draw researchers' attention to this promising field. The integration of knowledge about AFPs could pave the way for novel antifungal agents with broad-spectrum activity, reduced toxicity, targeted action, and mechanisms that limit resistance in pathogenic fungi, offering significant advancements in antifungal therapeutics.

Candida guilliermondii fungemia: a 12-year retrospective review of antimicrobial susceptibility patterns at a reference laboratory and tertiary care center

The prevalence of invasive candidiasis caused by non-albicans Candida species is increasing. Candida guilliermondii is an infrequent cause of candidemia but has been associated with decreased susceptibility to triazoles. Clinical data related to the infection with C. guilliermondii are sparse. Our study evaluated the antifungal susceptibility testing (AST) for C. guilliermondii isolates submitted to a reference laboratory over a 12-year period (2012-2023). AST patterns were examined using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) epidemiological cutoff values (ECVs) and breakpoints. Where isolates were identified from patients treated at our institution, retrospective chart review was performed to describe patient risk factors, treatment approaches, and outcomes associated with C. guilliermondii fungemia. One hundred twelve blood culture isolates of C. guilliermondii were identified, and clinical data were available for 21 fungemic patients. A significant number of isolates (9.8-20.5%) were observed to be non-wild type for various triazoles. All isolates were susceptible to micafungin. A majority (76.2%) of cases of C. guilliermondii fungemia treated at our tertiary care center were hospital-acquired, and two-thirds of patients were immunocompromised at the time of diagnosis. Ten of the 21 patients died within 60 days of fungemia, although mortality was directly or partially attributed to C. guilliermondii fungemia in only four cases (19.0%). Echinocandins may be used for empiric therapy for C. guilliermondii until the results of AST are available. Further research is required to determine appropriate clinical breakpoints for triazoles.

IMPORTANCE

Our study addresses a significant knowledge gap in the clinical management of this non-Candida albicans species. Our retrospective review includes comprehensive AST data for 112 Candida guilliermondii isolates, which is the largest number of isolates reported from the United States to date. Susceptibility data are supplemented by clinical outcomes, where isolates were identified for patients treated at Mayo Clinic. Key findings from our study include the observation that a notable proportion of C. guilliermondii isolates exhibit non-wild-type profiles for various triazoles. Importantly, all isolates remained susceptible to echinocandins, suggesting their efficacy as first-line therapy in the absence of timely susceptibility results. Furthermore, our study highlights the high mortality associated with C. guilliermondii fungemia in immunocompromised patients, emphasizing the urgent need for optimized treatment strategies.

Investigating role of positively selected genes and mutation sites of ERG11 in drug resistance of Candida albicans

The steep increase in acquired drug resistance in Candida isolates has posed a great challenge in the clinical management of candidiasis globally. Information of genes and codon sites that are positively selected during evolution can provide insights into the mechanisms driving antifungal resistance in Candida. This study aimed to create a manually curated list of genes of Candida spp. reported to be associated with antifungal resistance in literature, and further investigate the structure-function implications of positively selected genes and mutation sites. Sequence analysis of antifungal drug resistance associated gene sequences from various species and strains of Candida revealed that ERG11 and MRR1 of C. albicans were positively selected during evolution. Four sites in ERG11 and two sites in MRR1 of C. albicans were positively selected and associated with drug resistance. These four sites (132, 405, 450, and 464) of ERG11 are predictive markers for azole resistance and have evolved over time. A well-characterized crystal structure of sterol-14-α-demethylase (CYP51) encoded by ERG11 is available in PDB. Therefore, the stability of CYP51 in complex with fluconazole was evaluated using MD simulations and molecular docking studies for two mutations (Y132F and Y132H) reported to be associated with azole resistance in literature. These mutations induced high flexibility in functional motifs of CYP51. It was also observed that residues such as I304, G308, and I379 of CYP51 play a critical role in fluconazole binding affinity. The insights gained from this study can further guide drug design strategies addressing antimicrobial resistance.

Global research trends and hotspots on human intestinal fungi and health: a bibliometric visualization study

Background

This article employs bibliometric methods and visual maps to delineate the research background, collaborative relationships, hotspots, and trends in the study of gut fungi in human diseases and health.

Methods

Publications related to human gut fungi were retrieved from the Web of Science Core Collection. VOSviewer, CiteSpace, R software and Microsoft Excel were employed to generate visual representations illustrating the contributions made by countries/regions, authors, organizations, and journals. Employing VOSviewer and CiteSpace, we conducted a comprehensive analysis of the retrieved publications, revealing underlying tendencies, research hotspots, and intricate knowledge networks.

Results

This study analyzed a total of 3,954 publications. The United States ranks first in the number of published papers and has the highest number of citations and h-index. Mostafa S Elshahed is the most prolific author. The University of California System is the institution that published the most papers. Frontiers In Microbiology is the journal with the largest number of publications. Three frequently co-cited references have experienced a citation burst lasting until 2024.

Conclusion

Advancements in sequencing technologies have intensified research into human gut fungi and their health implications, shifting the research focus from gut fungal infections towards microbiome science. Inflammatory bowel diseases and Candida albicans have emerged as pivotal areas of interest in this endeavor. Through this study, we have gained a deeper insight into global trends and frontier hotspots within this field, thereby enhancing our understanding of the intricate relationship between gut fungi and human health.

A novel pH-responsive monomer inhibits Candida albicans via a dual antifungal mode of action

The scarcity of the antifungal drug arsenal highlights an urgent need to develop alternative treatments for candidiasis caused by Candida albicans (C. albicans). As pH is closely associated with C. albicans infection, it could be an essential target in a novel approach for designing antifungal therapy. In this study, a novel intelligent antifungal monomer, dodecylmethylaminoethyl methacrylate (DMAEM), with a pH-responsive tertiary amine group and a methacrylate-derived CC double bond group is developed. It is uncovered that the two functional groups of DMAEM contribute to a dual mode of action. Under acidic pH, the tertiary amine of DMAEM protonates into a cationic fungicide, sharing similar structural and functional characteristics with quaternary ammonium salts, which exerts fungicidal activity by targeting the CHK1 two-component system in C. albicans. At neutral pH, the methacrylate-derived CC double bond group contributes to anti-virulence activity by blocking hyphal formation. In addition, it is also identified that DMAEM suppresses filamentation by altering the extracellular vesicles of C. albicans. These findings support that the novel intelligent pH-responsive monomer could be a therapeutic candidate for treating candidiasis.

Development of multiplex real-time PCR for simultaneous detection of common fungal pathogens in invasive mycoses

Background

Fungi are common opportunistic pathogens that pose a significant threat to immunocompromised patients, particularly when late detection occurs.

Methods

In this study a multiplex real-time PCR has been developed for simultaneous detection of common fungal pathogens associated with invasive mycoses in a diagnostic setting.

Results

The specificity of the assay was rigorously tested on 40 types of organisms (n = 65), demonstrating 100% specificity. The limit of detection was determined to be 100 pg/μl (106 copies/μl), achievable within a rapid 3-h timeframe. The PCR assay efficiency exhibited a range between 89.77% and 104.30% for each target organism, with linearity falling between 0.9780 and 0.9983.

Conclusion

This multiplex real-time PCR assay holds promise for enhancing the timely and accurate diagnosis of invasive mycoses, particularly in immunocompromised patient populations.

Antifungal Efficacy of Ultrashort β-Peptides against Candida Species: Mechanistic Understanding and Therapeutic Implications

Candidiasis, a condition spurred by the unchecked proliferation of Candida species, poses a formidable global health threat, particularly in immunocompromised individuals. The emergence of drug-resistant strains complicates management strategies, necessitating novel therapeutic avenues. Antimicrobial peptides (AMPs) have garnered attention for their potent antifungal properties and broad-spectrum activity against Candida species. This study assessed the antifungal effectiveness of ultrashort β-peptides against Candida strains, with a specific focus on peptide P3 (LAU-β3,3-Pip-β2,2-Ac6c-PEA). Our findings showed P3's remarkable fungistatic and fungicidal activities against Candida albicans, exhibiting an MIC of 4 μg/mL, comparable to those of standard antifungal drugs. The MIC value remained unchanged in the presence of ADC and BSA, indicating that serum albumin does not diminish the activity of P3. P3 demonstrates synergistic effects when combined with Fluconazole (FLU), Itraconazole (ITR), and Nystatin (NYS) to the extent that it becomes effective at 0.125, 0.125, and 0.03125 μg/mL, respectively. Concentration versus time-kill kinetics showed its time-dependent activity up to the first 12 h against C. albicans, and later concentration also played a role; indeed, at 24 h the whole culture was sterilized at 8× MIC. Post-antifungal effect assays confirmed prolonged suppression of pathogen growth after the removal of P3 from the media for significant durations. More importantly, P3 inhibits hyphae formation and biofilm development of Candida, outperforming Fluconazole with respect to these properties. Mechanistic insights display P3's potential to disrupt fungal cell membrane integrity and dose-dependent inhibition of ergosterol biosynthesis, essential for fungal cell wall integrity. Using the Bradford assay, it was observed that extracellular protein concentrations increased with higher doses of the compound, thereby validating the effect of P3 on membrane integrity. A comparative gene analysis using RT-PCR showed that P3 downregulates ERG3, ERG11, and HWP1, which are crucial for the survival and pathogenicity of C. albicans. The impact of P3 on ERG11 and ERG3 is more effective than that of Fluconazole. Molecular docking studies revealed strong binding of P3 to various isoforms of lanosterol 14-α-demethylase, a key enzyme in ergosterol synthesis. Furthermore, molecular dynamic simulations validated the stability of the most promising docking complex. Overall, our findings underscore P3's potential as a leading candidate for the development of innovative antifungal therapies, warranting further investigation and optimization.

Prevalence, Species Distribution and Resistance of Candidemia in Pediatric and Adult Patients in a Northeast Italy University Hospital

Candidemia and invasive candidiasis (IC) are causes of morbidity and mortality in healthcare settings, with notable differences between children and adults. Understanding the species distribution and antimicrobial susceptibility profiles of clinical isolates can guide empiric therapy in patients at risk of IC. This study investigated the incidence and antifungal susceptibility patterns of yeasts involved in IC in pediatric and adult patients from 2019 to 2023. The average incidence of IC was 0.715 per 1000 patients, increasing over the study period; infants had the highest incidence rates. Over half of the IC episodes occurred in intensive care units (ICUs). Non-albicans Candida (NAC) species represented the most frequently isolated species in adults and children (55.96% and 50.0%, respectively), with the prevalence of C. parapsilosis (26.45% and 14.7%, respectively), N. glabratus (14.97% and 8.82%, respectively) and C. tropicalis (4.36% and 2.94%, respectively). C. lusitaniae was identified in 14.7% of pediatric IC cases. In NAC species, antifungal resistance has also increased over the five years of the study: 69.12% were resistant to azoles and 7.35% were resistant to micafungin. Resistance was higher in pediatric patients. Our study highlights differences in IC characteristics between pediatric and adult populations and emphasizes the importance of targeted antifungal stewardship in ICU patients with NAC invasive infections.

Emerging Fungal Infections of the Central Nervous System in the Past Decade: A Literature Review

INTRODUCTION

Invasive fungal infections affecting the central nervous system (CNS) are a major health concern worldwide associated with high mortality rates. Their increased incidence is largely due to an increase in the vulnerable immunocompromised population, changing environmental factors, and development of more accurate diagnostic methods. The aim of this article is to identify fungal causes of CNS infections that are recently emerging or have the potential to become emerging pathogens in the near future, as well as their clinical characteristics, including: Candida auris, Trichosporon spp., Blastomyces spp., Sporothrix spp., Talaromyces marneffei, Lomentospora prolificans, and Scedosporium spp.

METHODS

A review of the literature in PubMed in the last ten years was conducted to identify central nervous system infections caused by each of these fungi.

RESULTS

The review identified 10 cases caused by C. auris, 5 cases by Trichosporon spp., 82 cases by Blastomyces spp., 36 cases by Sporothrix spp., 21 cases by T. marneffei, 22 cases by Lomentospora prolificans, and 42 cases by Scedosporium spp.

DISCUSSION

The exact burden of these diseases remains difficult to ascertain, but their apparent rise underscores the urgent need for improved diagnostic, treatment, and management strategies against CNS fungal pathogens to improve outcomes against these life-threatening infections.

Invasive Fungal Infections in Immunocompromised Conditions: Emphasis on COVID-19

The COVID-19 pandemic caused death of 6 million lives globally, primarily from respiratory failure, but also a significant number from invasive fungal co-infections in these patients, owing to the immune dysfunction in hospitalized patients. Such complications occurred more often in critically ill, hospitalized patients particularly those admitted in intensive care units and were reported as the major reason associated with a high mortality rate worldwide. Fungal pathogens most commonly associated with COVID-19 patients comprise members of the Mucorales (such as Rhizopus, Mucor, and Lichtheimia), as well as genera Aspergillus and Candida. In India, the prevalence rate of mucormycosis is relatively high than aspergillosis and candidiasis, and the predisposing risk factors associated with such infections included uncontrolled diabetes, underlying lung disease, leukopenia, neutropenia, malignancies and prolonged steroid therapy. However, co-infection with other fungi, including Alternaria and Scedosporium was also sporadically reported. These devastating invasive fungal infections are associated with differential mortality (high-low) and morbidity rates even after active management. The diagnosis of such infections is often challenging due to lack of sensitivity in contemporary diagnostic methods and poses an enormous challenge to healthcare experts. Thus, the role of early and accurate diagnosis, and management of such fungal infections, is vital in preventing life-threatening situations. Hence, this review focusses primarily on the epidemiology, predisposing risk factors, host environment, diagnosis and treatment of the most common medically important invasive fungal infections in immunocompromised conditions associated with COVID-19.

The activating receptor NKG2D is an anti-fungal pattern recognition receptor

NKG2D is a central activating receptor involved in target recognition and killing by Natural Killer and CD8+ T cells. The known role of NKG2D is to recognize a family of self-induced stress ligands that are upregulated on stressed cells such as cancerous or virally infected cells. Fungal pathogens are a major threat to human health, infecting more than a billion patients yearly and becoming more common and drug resistant. Here we show that NKG2D plays a critical role in the immune response against fungal infections. NKG2D can recognize fungal pathogens from most major families including Candida, Cryptococcus and Aspergillus species, and mice lacking NKG2D are extremely sensitive to fungal infections in models of both invasive and mucosal infections, making NKG2D an anti-fungal pattern recognition receptor.

Azole Combinations and Multi-Targeting Drugs That Synergistically Inhibit Candidozyma auris

Limited antifungal treatment options and drug resistance require innovative approaches to effectively combat fungal infections. Combination therapy is a promising strategy that addresses these pressing issues by concurrently targeting multiple cellular sites. The drug targets usually selected for combination therapy are from different cellular pathways with the goals of increasing treatment options and reducing development of resistance. However, some circumstances can prevent the implementation of combination therapy in clinical practice. These could include the increased risk of adverse effects, drug interactions, and even the promotion of drug resistance. Furthermore, robust clinical evidence supporting the superiority of combination therapy over monotherapy is limited and underscores the need for further research. Despite these challenges, synergies detected with different antifungal classes, such as the azoles and echinocandins, suggest that treatment strategies can be optimized by better understanding the underlying mechanisms. This review provides an overview of multi-targeting combination strategies with a primary focus on Candidozyma auris infections.

Invasive candidiasis in a pediatric tertiary hospital: Epidemiology, antifungal susceptibility, and mortality rates

Invasive infections caused by non-albicans Candida are increasing worldwide. However, there is still a lack of information on invasive candidiasis (IC) in the pediatric setting, including susceptibility profiles and clonal studies. We investigated the clinical, epidemiologic, and laboratory characteristics of IC, possible changes in antifungal susceptibility profiles over time, and the occurrence of clonality in our tertiary children's hospital. We analyzed 123 non-duplicate Candida isolates from sterile sites of pediatric patients in a tertiary hospital in southern Brazil, between 2016 and 2021. Data on demographics, comorbidities, and clinical outcomes were collected. Candida species distribution, antifungal susceptibility profiles, biofilm production, and molecular epidemiology of isolates were assessed using reference methods. The range of IC incidence was 0.88-1.55 cases/1000 hospitalized patients/year, and the IC-related mortality rate was 20.3%. Of the total IC cases, 42.3% were in patients aged < 13 months. Mechanical ventilation, parenteral nutrition, and intensive care unit (ICU) admission were common in this group. In addition, ICU admission was identified as a risk factor for IC-related mortality. The main site of Candida spp. isolation was blood, and non-albicans Candida species were predominant (70.8%). No significant clonal spread was observed among isolates of the three most commonly isolated species, and 99.1% of all isolates were biofilm producers. Non-albicans Candida species were predominant in this study. Notably, clonal expansion and emergence of antifungal drug resistance were not observed in our pediatric setting.

Unveiling the antifungal mechanisms of CTP, a new copper(II)-theophylline/1,10-phenanthroline complex, on drug-resistant non-albicans Candida species

Candida species undeniably rank as the most prevalent opportunistic human fungal pathogens worldwide, with Candida albicans as the predominant representative. However, the emergence of non-albicans Candida species (NACs) has marked a significant shift, accompanied by rising incidence rates and concerning trends of antifungal resistance. The search for new strategies to combat antifungal-resistant Candida strains is of paramount importance. Recently, our research group reported the anti-Candida activity of a coordination compound containing copper(II) complexed with theophylline (theo) and 1,10-phenanthroline (phen), known as "CTP" - Cu(theo)2phen(H2O).5H2O. In the present work, we investigated the mechanisms of action of CTP against six medically relevant, antifungal-resistant NACs, including C. auris, C. glabrata, C. haemulonii, C. krusei, C. parapsilosis and C. tropicalis. CTP demonstrated significant efficacy in inhibiting mitochondrial dehydrogenases, leading to heightened intracellular reactive oxygen species production. CTP treatment resulted in substantial damage to the plasma membrane, as evidenced by the passive incorporation of propidium iodide, and induced DNA fragmentation as revealed by the TUNEL assay. Scanning electron microscopy images of post-CTP treatment NACs further illustrated profound alterations in the fungal surface morphology, including invaginations, cavitations and lysis. These surface modifications significantly impacted the ability of Candida cells to adhere to a polystyrene surface and to form robust biofilm structures. Moreover, CTP was effective in disassembling mature biofilms formed by these NACs. In conclusion, CTP represents a promising avenue for the development of novel antifungals with innovative mechanisms of action against clinically relevant NACs that are resistant to antifungals commonly used in clinical settings.

Antibiotics stimulates the development of persistent cells in biofilms of Candida albicans bloodstream isolates

Candida albicans invasive candidiasis is considered a global health problem. In such cases, biofilm formation on implanted devices represents a therapeutic challenge and the presence of metabolically inactive persistent cells (PCs) in these communities increases their tolerance to fungicidal drugs. This study investigated the influence of amoxicillin, AMX; cefepime, CEF; gentamicin, GEN; amikacin, AMK; vancomycin, VAN; and ciprofloxacin, CIP; on the production of PCs in biofilms of C. albicans bloodstream isolates. 48 h-mature biofilms (n = 6) grown in RPMI-1640 supplemented with antibiotics were treated with 100 μg ml-1 amphotericin B and then evaluated for PCs. Biofilms grown in the presence of antibiotics produced more PCs, up to 10×, when exposed to AMX and CIP; 5 × to CEF; and 6 × to GEN and VAN. The results indicate that antibiotics can modulate PC production in C. albicans biofilms. This scenario may have clinical repercussions in immunocompromised patients under broad-spectrum antibiotic therapy.

Candidemia Following Severe COVID-19 in Hospitalised and Critical Ill Patients: A Systematic Review and Meta-Analysis

RATIONALE

The epidemiology and clinical impact of COVID-19-associated candidemia (CAC) remained uncertain, leaving gaps in understanding its prevalence, risk factors and outcomes.

METHODS

A systematic review and meta-analysis were conducted by searching PubMed, Embase and Scopus for reports of CAC prevalence, risk factors and clinical outcomes up to June 18, 2024. The generalised linear mixed model was employed to determine the prevalence and 95% confidence intervals (CIs). The risk factors and clinical outcomes were compared between patients with and without CAC using the inverse variance method.

RESULTS

From 81 studies encompassing 29 countries and involving 351,268 patients, the global prevalence of CAC was 4.33% (95% Cl, 3.16%-5.90%) in intensive care unit (ICU) patients. In ICUs, the pooled prevalence of CAC in high-income countries was significantly higher than that of lower-middle-income countries (5.99% [95% Cl, 4.24%-8.40%] vs. 2.23% [95% Cl, 1.06%-4.61%], p = 0.02). Resistant Candida species, including C. auris, C. glabrata (Nakaseomyces glabratus) and C. krusei (Pichia kudriavzveii), constituted 2% of ICU cases. The mortality rate for CAC was 68.40% (95% Cl, 61.86%-74.28%) among ICU patients. Several risk factors were associated with CAC, including antibiotic use, central venous catheter placement, dialysis, mechanical ventilation, tocilizumab, extracorporeal membrane oxygenation and total parenteral nutrition. Notably, the pooled odds ratio of tocilizumab was 2.59 (95% CI, 1.44-4.65).

CONCLUSIONS

The prevalence of CAC is substantial in the ICU setting, particularly in high-income countries. Several risk factors associated with CAC were identified, including several that are modifiable, offering the opportunity to mitigate the risk of CAC.

Successful combined treatment with surgery and ALA-PDT for cutaneous infection by candida tropicalis: A case report and literature review

Candidiasis is a common fungal infection, with Candida tropicalis infections being relatively rare. These infections develop into skin fungal infections under conditions such as broad-spectrum antibiotic use, diabetes, and immunosuppression. Traditionally, antifungal drugs have been the primary treatment; however, issues like hepatotoxicity and the need for long-term use persist. Consequently, new treatment approaches are essential. Most previous reports have focused on Candida albicans, with fewer addressing Candida tropicalis. This study reports a case where a patient with a skin Candida tropicalis infection was treated with a combination of surgery and ALA photodynamic therapy(635 nm, 120 J/cm2, 177 mW/cm2). After just one session of this combined treatment, the patient achieved significant clinical remission. Therefore, the combination of surgery and ALA-PDT may offer a safe and effective treatment option.

Discovery of petroselinic acid with in vitro and in vivo antifungal activity by targeting fructose-1,6-bisphosphate aldolase

BACKGROUND

The incidence of invasive fungal diseases (IFDs), represented by Candida albicans infection, is increasing year by year. However, clinically available antifungal drugs are very limited and encounter challenges such as limited efficacy, drug resistance, high toxicity, and exorbitant cost. Therefore, there is an urgent need for new antifungal drugs.

PURPOSE

This study aims to find new antifungal compounds from plants, preferably those with good activity and low toxicity, and reveal their antifungal targets.

METHODS

In vitro antifungal activities of compounds were investigated using broth microdilution method, spot assay, hyphal growth assay and biofilm formation assay. Synergistic effects were assessed using broth microdilution checkerboard technique. In vivo antifungal activities were evaluated using Galleria mellonella and murine candidiasis models. Cytotoxicity of compounds was investigated using Cell Counting Kit-8 (CCK-8). Discovery and validation of antifungal targets of compounds were conducted by using monoallelic knockout library of C. albicans, haploinsufficiency profiling (HIP), thermal shift assay (TSA), enzyme inhibitory effect assay, molecular docking, and in vitro and in vivo antifungal studies.

RESULTS

814 plant products were screened, among which petroselinic acid (PeAc) was found as an antifungal molecule. As a rare fatty acid isolated from coriander (Coriandrum sativum), carrot (Daucus carota) and other plants of the Apiaceae family, PeAc had not previously been found to have antifungal effects. In this study, PeAc was revealed to inhibit the growth of various pathogenic fungi, exhibited synergistic effects with fluconazole (FLC), inhibited the formation of C. albicans hyphae and biofilms, and showed antifungal effects in vivo. PeAc was less toxic to mammalian cells. Fructose-1,6-bisphosphate aldolase (Fba1p) was identified as a target of PeAc by using HIP, TSA, enzyme inhibitory effect assay and molecular docking methods. PeAc exerted antifungal effects more effectively on fba1Δ/FBA1 than wild-type (WT) strain both in vitro and in vivo.

CONCLUSIONS

PeAc is an effective and low toxic antifungal compound. The target of PeAc is Fba1p. Fba1p is a promising target for antifungal drug development.

Recent Challenges in Diagnosis and Treatment of Invasive Candidiasis in Neonates

Invasive Candida infections represent a significant cause of morbidity and mortality in the neonatal intensive care unit (NICU), particularly among preterm and low birth weight neonates. The nonspecific clinical presentation of invasive candidiasis, resembling that of bacterial sepsis with multiorgan involvement, makes the diagnosis challenging. Given the atypical clinical presentation and the potential detrimental effects of delayed treatment, empirical treatment is often initiated in cases with high clinical suspicion. This underscores the need to develop alternative laboratory methods other than cultures, which are known to have low sensitivity and a prolonged detection time, to optimize therapeutic strategies. Serum biomarkers, including mannan antigen/anti-mannan antibody and 1,3-β-D-glucan (BDG), both components of the yeast cell wall, a nano-diagnostic method utilizing T2 magnetic resonance, and Candida DNA detection by PCR-based techniques have been investigated as adjuncts to body fluid cultures and have shown promising results in improving diagnostic efficacy and shortening detection time in neonatal populations. This review aims to provide an overview of the diagnostic tools and the current management strategies for invasive candidiasis in neonates. Timely and accurate diagnosis followed by targeted antifungal treatment can significantly improve the survival and outcome of neonates affected by Candida species.

Liquid-liquid phase separation: a new perspective on respiratory diseases

Liquid-liquid phase separation (LLPS) is integral to various biological processes, facilitating signal transduction by creating a condensed, membrane-less environment that plays crucial roles in diverse physiological and pathological processes. Recent evidence has underscored the significance of LLPS in human health and disease. However, its implications in respiratory diseases remain poorly understood. This review explores current insights into the mechanisms and biological roles of LLPS, focusing particularly on its relevance to respiratory diseases, aiming to deepen our understanding and propose a new paradigm for studying phase separation in this context.

Treatment Outcomes Among Patients With a Positive Candida Culture Close to Randomization Receiving Rezafungin or Caspofungin in the ReSTORE Study

BACKGROUND

Rezafungin, a novel, once-weekly echinocandin for the treatment of candidemia and/or invasive candidiasis (IC) was noninferior to caspofungin for day 30 all-cause mortality (ACM) and day 14 global cure in the phase 3 ReSTORE trial (NCT03667690). We conducted preplanned subgroup analyses for patients with a positive culture close to randomization in ReSTORE.

METHODS

ReSTORE was a multicenter, double-blind, double-dummy, randomized trial in patients aged ≥18 years with candidemia and/or IC treated with once-weekly intravenous rezafungin (400 mg/200 mg) or once-daily intravenous caspofungin (70 mg/50 mg). This analysis comprised patients with a positive blood culture drawn between 12 hours before and 72 hours after randomization or a positive culture from another normally sterile site sampled between 48 hours before and 72 hours after randomization. Efficacy endpoints included day 30 ACM, day 14 global cure rate, and day 5 and 14 mycological response. Adverse events were evaluated.

RESULTS

This analysis included 38 patients randomized to rezafungin and 46 to caspofungin. In the rezafungin and caspofungin groups, respectively, day 30 ACM was 26.3% and 21.7% (between-group difference [95% confidence interval], 4.6% [-13.7%, 23.5%]), day 14 global response was 55.3% and 50.0% (between-group difference, 5.3% [-16.1%, 26.0%]), and day 5 mycological eradication was 71.1% and 50.0% (between-group difference, 21.1% [-0.2%, 40.2%]). Safety was comparable between treatments.

CONCLUSIONS

These findings support the efficacy and safety of rezafungin compared with caspofungin for the treatment of candidemia and/or IC in patients with a positive culture close to randomization, with potential early treatment benefits for rezafungin.

Nanomaterial-based therapeutics for enhanced antifungal therapy

The application of nanotechnology in antifungal therapy is gaining increasing attention. Current antifungal drugs have significant limitations, such as severe side effects, low bioavailability, and the rapid development of resistance. Nanotechnology offers an innovative solution to address these issues. This review discusses three key strategies of nanotechnology to enhance antifungal efficacy. Firstly, nanomaterials can enhance their interaction with fungal cells via ingenious surface tailoring of nanomaterials. Effective adhesion of nanoparticles to fungal cells can be achieved by electrostatic interaction or specific targeting to the fungal cell wall and cell membrane. Secondly, stimuli-responsive nanomaterials are developed to realize smart release of drugs in the specific microenvironment of pathological tissues, such as the fungal biofilm microenvironment and inflammatory microenvironment. Thirdly, nanomaterials can be designed to cross different physiological barriers, effectively addressing challenges posed by skin, corneal, and blood-brain barriers. Additionally, some new nanomaterial-based strategies in treating fungal infections are discussed, including the development of fungal vaccines, modulation of macrophage activity, phage therapy, the application of high-throughput screening in drug discovery, and so on. Despite the challenges faced in applying nanotechnology to antifungal therapy, its significant potential and innovation open new possibilities for future clinical antifungal applications.

Candida albicans N-Linked Mannans Potentiate the Induction of Trained Immunity via Dectin-2

The interaction between the Candida albicans cell wall and pattern recognition receptors is crucial for the initiation of host immune responses, which, ultimately, contribute to the clearance of this pathogenic fungus. In the present study, we investigate the ability of C. albicans mannans to modulate immune response and induce innate immune memory (also termed trained immunity). Using mutants of C. albicans that are defective in or lack mannosyl residues, we show that alterations in the mannosylation of the C. albicans cell wall affect the innate cytokine response and strongly reduce the secretion of T-cell-derived cytokines. Subsequently, we demonstrate that the branching of N-linked mannan, but not O-linked mannan, is essential to potentiate the induction of trained immunity, a process mediated by dectin 2. In conclusion, N-linked mannan is needed, in addition to β-glucans, for an effective induction of trained immunity by C. albicans.

Unveiling novel insights: geraniol's enhanced anti-candida efficacy and mechanistic innovations against multidrug-resistant candida strains

OBJECTIVES

This study addressed the need for new treatments for severe Candida infections, especially resistant strains. It evaluated the antifungal potential of geraniol alone and with fluconazole against various Candida spp., including resistant strains, and investigated geraniol's mechanism of action using flow cytometry.

METHODS

The research assessed the inhibitory effects of geraniol on the growth of various Candida species at concentrations ranging from 110 to 883 µg/ml. The study also explored the potential synergistic effects when geraniol was combined with fluconazole. The mechanism of action was investigated through flow cytometry, with a particular emphasis on key enzymes associated with plasma membrane synthesis, membrane permeability changes, mitochondrial membrane depolarization, reactive oxygen species (ROS) induction, and genotoxicity.

RESULTS

Geraniol demonstrated significant antifungal activity against different Candida species, inhibiting growth at concentrations within the range of 110 to 883 µg/ml. The mechanism of action appeared to be multifactorial. Geraniol was associated with the inhibition of crucial enzymes involved in plasma membrane synthesis, increased membrane permeability, induction of mitochondrial membrane depolarization, elevated ROS levels, and the presence of genotoxicity. These effects collectively contributed to cell apoptosis.

CONCLUSIONS

Geraniol, alone and in combination with fluconazole, shows promise as a potential therapeutic option for Candida spp.

INFECTIONS

Its diverse mechanism of action, impacting crucial cellular processes, highlights its potential as an effective antifungal agent. Further research into geraniol's therapeutic applications may aid in developing innovative strategies to address Candida infections, especially those resistant to current therapies.

Diagnosing fungal infections in clinical practice: a narrative review

BACKGROUND

Invasive fungal infections (IFI) present a major medical challenge, with an estimated 6.5 million cases annually, resulting in 3.8 million deaths. Pathogens such as Aspergillus spp. Candida spp. Mucorales spp. Cryptococcus spp. and other fungi species contribute to these infections, posing risks to immunocompromised individuals. Early and accurate diagnosis is crucial for effective treatment and better patient outcomes.

AREAS COVERED

This narrative review provides an overview of the current methods and challenges associated with diagnosing fungal diseases, including invasive aspergillosis and invasive candidiasis, as well as rare and endemic fungal infections. Various diagnostic techniques, including microscopy, culture, molecular diagnostics, and serological tests, are reviewed, highlighting their respective advantages and limitations and role in clinical guidelines. To illustrate, the need for improved diagnostic strategies to overcome existing challenges, such as the low sensitivity and specificity of current tests and the time-consuming nature of traditional culture-based methods, is addressed.

EXPERT OPINION

Current advancements in fungal infection diagnostics have significant implications for healthcare outcomes. Improved strategies like molecular testing and antigen detection promise early detection of fungal pathogens, enhancing patient management. Challenges include global access to advanced technologies and the need for standardized, user-friendly point-of-care diagnostics to improve diagnosis of fungal infections globally.

Antimicrobial and antibiofilm activities of Inga cylindrica trypsin inhibitor

Inga cylindrica, a tropical fruit tree of the Fabaceae family (subfamily Mimosoideae), is native to South America. The seeds from this family are an essential source of trypsin inhibitors, which display promising bioactivity for increasing host defense against pathogens. The aim of the present study was to characterize the antimicrobial and antibiofilm activities of the trypsin inhibitor extracted from I. cylindrica seeds, ICTI. ICTI demonstrated antifungal activity with a minimum inhibitory concentration (MIC) of 32.11 μmol.L-1, and a minimum fungicidal concentration (MFC) of 32.1 μmol.L-1, against Cryptococcus gattii, Candida albicans, Candida glabrata and Candida guilliermondii. Combining ICTI with Amphotericin B had a significant synergistic effect, reducing the concentration of the antibiotic by 75% for C. albicans and 94% for C. gatti. The significant increase (16 x) in activity observed with ergosterol (1.01 mol.L-1) for C. albicans and C. gatti, and the lack of activity against bacterial strains, suggests that ICTI interferes with the integrity of the fungal cell membrane. Treatment with ICTI at 10 x MIC resulted in a 51% reduction in biofilm formation and a 56% decrease in mature biofilm colonies for C. albicans. Finally, ICTI displayed no toxicity in the in vivo Galleria mellonella model. Given its antifungal and antibiofilm properties, ICTI could be a promising candidate for the development of new antimicrobial drug prototypes.

Controlling Candida: immune regulation of commensal fungi in the gut

The intestinal microbiome harbors fungi that pose a significant risk to human health as opportunistic pathogens and drivers of inflammation. Inflammatory and autoimmune diseases are associated with dysbiotic fungal communities and the expansion of potentially pathogenic fungi. The gut is also the main reservoir for disseminated fungal infections. Immune interactions are critical for preventing commensal fungi from becoming pathogenic. Significant strides have been made in defining innate and adaptive immune pathways that regulate intestinal fungi, and these discoveries have coincided with advancements in our understanding of the fungal molecular pathways and effectors involved in both commensal colonization and pathogenesis within the gut. In this review, we will discuss immune interactions important for regulating commensal fungi, with a focus on how specific cell types and effectors interact with fungi to limit their colonization or pathogenic potential. This will include how innate and adaptive immune pathways target fungi and orchestrate antifungal immune responses, in addition to how secreted immune effectors, such as mucus and antimicrobial peptides, regulate fungal colonization and inhibit pathogenic potential. These immune interactions will be framed around our current understanding of the fungal effectors and pathways regulating colonization and pathogenesis within this niche. Finally, we highlight important unexplored mechanisms by which the immune system regulates commensal fungi in the gut.

A machine learning model for early candidemia prediction in the intensive care unit: Clinical application

Candidemia often poses a diagnostic challenge due to the lack of specific clinical features, and delayed antifungal therapy can significantly increase mortality rates, particularly in the intensive care unit (ICU). This study aims to develop a machine learning predictive model for early candidemia diagnosis in ICU patients, leveraging their clinical information and findings. We conducted this study with a cohort of 334 patients admitted to the ICU unit at Ji Ning NO.1 people's hospital in China from Jan. 2015 to Dec. 2022. To ensure the model's reliability, we validated this model with an external group consisting of 77 patients from other sources. The candidemia to bacteremia ratio is 1:1. We collected relevant clinical procedures and eighteen key examinations or tests features to support the recursive feature elimination (RFE) algorithm. These features included total bilirubin, age, platelet count, hemoglobin, CVC, lymphocyte, Duration of stay in ICU and so on. To construct the candidemia diagnosis model, we employed random forest (RF) algorithm alongside other machine learning methods and conducted internal and external validation with training and testing sets allocated in a 7:3 ratio. The RF model demonstrated the highest area under the receiver operating characteristic (AUC) with values of 0.87 and 0.83 for internal and external validation, respectively. To evaluate the importance of features in predicting candidemia, Shapley additive explanation (SHAP) values were calculated and results revealed that total bilirubin and age were the most important factors in the prediction model. This advancement in candidemia prediction holds significant promise for early intervention and improved patient outcomes in the ICU setting, where timely diagnosis is of paramount crucial.

UPLC-MS/MS method for fluconazole determination in plasma and its application in Mexican patients with candidaemia

Aim: An accurate and fast ultra-high performance liquid chromatography coupled with tandem mass spectrometry analytical method was developed and validated for quantifying fluconazole levels in human plasma according to the US FDA guidelines.Materials & methods: A simple protein precipitation by acetonitrile was employed for the sample preparation. The chromatographic separation was carried out using isocratic elution of water (0.1% formic acid) and acetonitrile on an Acquity ultra-high performance liquid chromatography HSS T3 column. Samples from ten adult patients diagnosed with candidemia who received fluconazole treatment were analyzed.Results & conclusion: The method demonstrated excellent linearity and stability within the 1-50 μg/ml range (r2 >0.999). The intraday and interday precision were determined with coefficient of variation values ranging from 1.4 to 4.38% and 2.8 to 6.6%, respectively. This rapid and selective method has successfully analyzed 27 plasma samples. The straightforward sample preparation in a single step and the reduced analysis time make this method suitable for adult patients with candidemia, leading to improved clinical outcomes.

Transposon-sequencing (Tn-seq) of the Candida glabrata reference strain CBS138 reveals epigenetic plasticity, structural variation, and intrinsic mechanisms of resistance to micafungin

Candida glabrata (also called Nakaseomyces glabratus) is an opportunistic pathogen that can resist common antifungals and rapidly acquire multidrug resistance. A large amount of genetic variation exists between isolates, which complicates generalizations. Portable transposon-sequencing (Tn-seq) methods can efficiently provide genome-wide information on strain differences and genetic mechanisms. Using the Hermes transposon, the CBS138 reference strain and a commonly studied derivative termed 2001 were subjected to Tn-seq in control conditions and after exposure to varying doses of the clinical antifungal micafungin. The approach revealed large differences between these strains, including a 131-kb tandem duplication and a variety of fitness differences. Additionally, both strains exhibited up to 1,000-fold increased transposon accessibility in subtelomeric regions relative to the BG2 strain, indicative of open subtelomeric chromatin in these isolates and large epigenetic variation within the species. Unexpectedly, the Pdr1 transcription factor conferred resistance to micafungin through targets other than CDR1. Other micafungin resistance pathways were also revealed including mannosyltransferase activity and biosynthesis of the lipid precursor sphingosine, the inhibition of which by SDZ 90-215 and myriocin enhanced the potency of micafungin in vitro. These findings provide insights into the complexity of the C. glabrata species as well as strategies for improving antifungal efficacy.

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.

A novel quantitative double antigen sandwich ELISA for detecting total antibodies against Candida albicans enolase 1

PURPOSE

This study aimed to develop a double antigen sandwich ELISA (DAgS-ELISA) method for more efficient, accurate, and quantitative detection of total antibodies against Candida albicans enolase1 (CaEno1) for diagnosing invasive candidiasis (IC).

METHODS

DAgS-ELISA was developed using recombinant CaEno1 and a monoclonal antibody as the standard. Performance evaluation included limit of detection, accuracy, and repeatability. Dynamic changes in antibody levels against CaEno1 in serum from systemic candidiasis mice were analyzed using DAgS-ELISA. Patient serum samples from IC, Candida colonization, bacterial infections, and healthy controls were analyzed with DAgS-ELISA and indirect ELISA.

RESULTS

DAgS-ELISA outperformed indirect ELISA in terms of linear range and test background. In systemic candidiasis mice, a distinctive 'double-peak' pattern in dynamic antibody levels was observed. Additionally, there was a high level of consistency in the positive rates of CaEno1 antibodies detected by both DAgS-ELISA and indirect ELISA. While the positivity rates differed among patient groups, no significant variations in antibody levels were detected among the various positive patient groups.

CONCLUSIONS

DAgS-ELISA offers a reliable novel approach for IC diagnosis, enabling rapid, accurate, and quantitative detection of CaEno1 antibodies. Further validation and optimization are needed for its clinical application and effectiveness.

An Uncommon Manifestation of Systemic Lupus Erythematosus as Lupus Enteritis With Intestinal Pseudo-Obstruction and Invasive Candidiasis

Systemic lupus erythematosus (SLE) is a multifaceted autoimmune disorder, occasionally presenting with rare complications like lupus enteritis (LE) and intestinal pseudo-obstruction (IPO). We present a unique case of a 32-year-old woman with LE and IPO, complicated by invasive candidiasis, as an initial manifestation of SLE. The patient presented with a 15-day history of abdominal pain, vomiting, and poor oral intake, and was initially misdiagnosed with infective enterocolitis. Examination revealed abdominal distension and absent bowel sounds due to IPO, alongside severe hypokalemia and signs of intra-abdominal hypertension (IAH), necessitating ventilator support. Subsequent workup confirmed SLE with LE and associated lupus nephritis (LN). The patient's condition was further complicated by disseminated invasive candidiasis involving multiple organs, including the bloodstream, chorioretinitis, and endocarditis. Despite her critical state, intensive multidisciplinary care, including high-dose steroids, antifungal therapy, and supportive measures, led to her recovery and discharge after a 51-day ICU stay. This case underscores the complexity of diagnosing SLE when it presents with non-specific symptoms. The concomitant occurrence of LE, IPO, and invasive candidiasis is particularly rare, highlighting the need for high clinical suspicion in the presence of SLE serological activity. The presence of invasive candidiasis was likely secondary to gut translocation due to LE-associated inflammation, a phenomenon not previously well-documented. LE can manifest as the primary and sole presentation of SLE, even in the absence of typical lupus features. Prompt immunomodulatory treatment and comprehensive care are essential for a favorable outcome. Clinicians should consider invasive candidiasis in SLE patients with acute GI involvement, particularly in the presence of LE.

How can we optimize antifungal use and stewardship in the treatment of acute leukemia?

INTRODUCTION

The global need for antifungal stewardship is driven by spreading antimicrobial and antifungal resistance. Triazoles are the only oral and relatively well-tolerated class of antifungal medications, and usage is associated with acquired resistance and species replacement with intrinsically resistant organisms. On a per-patient basis, hematology patients are the largest inpatient consumers of antifungal drugs, but are also the most vulnerable to invasive fungal disease.

AREAS COVERED

In this review we discuss available and forthcoming antifungal drugs, antifungal prophylaxis and empiric antifungal therapy, and how a screening based and diagnostic-driven approach may be used to reduce antifungal consumption. Finally, we discuss components of an antifungal stewardship program, interventions that can be employed, and how impact can be measured. The search methodology consisted of searching PubMed for journal articles using the term antifungal stewardship plus program, intervention, performance measure or outcome before 1 January 2024.

EXPERT OPINION

Initial focus should be on implementing effective antifungal stewardship programs by developing and implementing local guidelines and using interventions, such as post-prescription review and feedback, which are known to be effective. Technologies such as microbiome analysis and machine learning may allow the development of truly individualized risk-factor-based approaches to antifungal stewardship in the future.

Candida Isolation During COVID-19: Microbiological Findings of a Prospective Study in a Regional Hospital

BACKGROUND

Prolonged hospitalization due to the COVID-19 pandemic gathered risk factors for developing invasive candidiasis.

AIM

To describe Candida spp. isolated from patients with clinical suspicion of COVID treated in a public hospital specialized in COVID-19 during the pandemic, considering the susceptibility profiles and the risk factors related to the species detected in a positive yeast culture.

METHODS

From different samples of 33 patients with comorbidities, 42 clinical isolates were identified by VITEKⓇ MS Plus. Antifungal susceptibility testing was performed using VITEKⓇ 2 Compact with the AST-YS08 card.

RESULTS

The most frequently identified species were C. albicans and C. glabrata, which were also the most common co-infections, Saprochaete capitata, an uncommon yeast was isolated in one patient. 85% of the co-infections were COVID positive and 100% of patients with a co-infection required mechanical ventilation (MV) which has been described as one of the major predisposing factors to candidiasis. Candida species vary in their response to treatment. In this study, 44% of isolates identified as C. glabrata were fluconazole-resistant, which were also immediately susceptible to caspofungin; this profile limits therapeutic options and emphasizes the importance of evaluating the susceptibility profile.

CONCLUSIONS

This work highlights the increase in isolation of different Candida species during COVID-19 and the importance of establishing criteria to declare Candida colonization or infection and the correct etiological identification to establish an agent-based antifungal treatment, to reduce the spreading risk of Candida spp. in the hospital environment, mortality, time, and cost of hospitalization.

New arsenals for old armour: Biogenic nanoparticles in the battle against drug-resistant Candidaalbicans

Candida albicans is a common commensal fungus and fourth most frequent causative agent of nosocomial infections including life-threatening invasive candidiasis in humans. The effectiveness of present antifungal therapies using azoles, polyenes, flucytosine and echinocandins has plateaued in managing fungal infections. The limitations of these antifungal drugs are related to polymorphic morphology, biofilm formation, emergence of drug-resistant strains and production of several virulence factors. Development of new antifungal agents, which can particularly afflict multiple cellular targets and limiting evolving resistant strains are needed. Recently, metal nanoparticles have emerged as a source of new antifungal agents for antifungal formulations. Furthermore, green nanotechnology deals with the use of biosynthetic routes that offer new avenue for synthesizing antifungal nanoparticles coupled with less toxic chemical inventory and environmental sustainability. This article reviews the recent developments on C. albicans pathogenesis, biofilm formation, drug resistance, mode of action of antifungal drugs and antifungal activities of metal nanoparticles. The antifungal efficacy and mode of action of metal nanoparticles are described in the context of prospective therapeutic applications.

Epidemiology of Invasive Candidiasis

Invasive candidiasis (IC) is an increasingly prevalent, costly, and potentially fatal infection brought on by the opportunistic yeast, Candida. Previously, IC has predominantly been caused by C. albicans which is often drug susceptible. There has been a global trend towards decreasing rates of infection secondary to C. albicans and a rise in non-albicans species with a corresponding increase in drug resistance creating treatment challenges. With advances in management of malignancies, there has also been an increase in the population at risk from IC along with a corresponding increase in incidence of breakthrough IC infections. Additionally, the emergence of C. auris creates many challenges in management and prevention due to drug resistance and the organism's ability to transmit rapidly in the healthcare setting. While the development of novel antifungals is encouraging for future management, understanding the changing epidemiology of IC is a vital step in future management and prevention.

Toll-like receptor 4 (TLR4) is the major pattern recognition receptor triggering the protective effect of a Candida albicans extracellular vesicle-based vaccine prototype in murine systemic candidiasis

Systemic candidiasis remains a significant public health concern worldwide, with high mortality rates despite available antifungal drugs. Drug-resistant strains add to the urgency for alternative therapies. In this context, vaccination has reemerged as a prominent immune-based strategy. Extracellular vesicles (EVs), nanosized lipid bilayer particles, carry a diverse array of native fungal antigens, including proteins, nucleic acids, lipids, and glycans. Previous studies from our laboratory demonstrated that Candida albicans EVs triggered the innate immune response, activating bone marrow-derived dendritic cells (BMDCs) and potentially acting as a bridge between innate and adaptive immunity. Vaccination with C. albicans EVs induced the production of specific antibodies, modulated cytokine production, and provided protection in immunosuppressed mice infected with lethal C. albicans inoculum. To elucidate the mechanisms underlying EV-induced immune activation, our study investigated pathogen-associated molecular patterns (PAMPs) and pattern recognition receptors (PRRs) involved in EVs-phagocyte engagement. EVs from wild-type and mutant C. albicans strains with truncated mannoproteins were compared for their ability to stimulate BMDCs. Our findings revealed that EV decoration with O- and N-linked mannans and the presence of β-1,3-glucans and chitin oligomers may modulate the activation of specific PRRs, in particular Toll-like receptor 4 (TLR4) and dectin-1. The protective effect of vaccination with wild-type EVs was found to be dependent on TLR4. These results suggest that fungal EVs can be harnessed in vaccine formulations to selectively activate PRRs in phagocytes, offering potential avenues for combating or preventing candidiasis.IMPORTANCESystemic candidiasis is a serious global health concern with high mortality rates and growing drug resistance. Vaccination offers a promising solution. A unique approach involves using tiny lipid-coated particles called extracellular vesicles (EVs), which carry various fungal components. Previous studies found that Candida albicans EVs activate the immune response and may bridge the gap between innate and adaptive immunity. To understand this better, we investigated how these EVs activate immune cells. We demonstrated that specific components on EV surfaces, such as mannans and glucans, interact with receptors on immune cells, including Toll-like receptor 4 (TLR4) and dectin-1. Moreover, vaccinating with these EVs led to strong immune responses and full protection in mice infected with Candida. This work shows how harnessing fungal EVs might lead to effective vaccines against candidiasis.

Functional genomic analysis of genes important for Candida albicans fitness in diverse environmental conditions

Fungal pathogens such as Candida albicans pose a significant threat to human health with limited treatment options available. One strategy to expand the therapeutic target space is to identify genes important for pathogen growth in host-relevant environments. Here, we leverage a pooled functional genomic screening strategy to identify genes important for fitness of C. albicans in diverse conditions. We identify an essential gene with no known Saccharomyces cerevisiae homolog, C1_09670C, and demonstrate that it encodes subunit 3 of replication factor A (Rfa3). Furthermore, we apply computational analyses to identify functionally coherent gene clusters and predict gene function. Through this approach, we predict the cell-cycle-associated function of C3_06880W, a previously uncharacterized gene required for fitness specifically at elevated temperatures, and follow-up assays confirm that C3_06880W encodes Iml3, a component of the C. albicans kinetochore with roles in virulence in vivo. Overall, this work reveals insights into the vulnerabilities of C. albicans.

Two outbreaks and sporadic occurrences of Candida auris from one hospital in China: an epidemiological, genomic retrospective study

OBJECTIVES

To investigate the clinical relevance, origin, transmission, and resistance of Candida auris (C. auris) isolates from two outbreaks and sporadic occurrences from one hospital in China.

METHODS

A total of 135 C. auris isolates were collected. Clinical characteristics were obtained and antifungal susceptibility testing (AFST) was performed using the method of broth microdilution. Phylogenetic tree, WGS analysis, and single nucleotide polymorphisms (SNPs) were used to determine the origin, transmission, and resistance mechanisms.

RESULTS

A total of 31 patients (91.2%, 31/34) received invasive medical procedures and 13 patients (38.2%, 13/34) had antifungal agents before C. auris infection/colonization, except one patient whose clinical information was missing. Only 4 cases of C. auris candidemia were observed. 18 patients died, 13 patients recovered, and the outcomes of 3 patients were not available. A total of 35 C. auris isolates, which were successfully cultivated and the first isolated or harbored specific drug-resistant phenotype from each patient, were selected to be sequenced and further analyzed. C. auris isolates presented low genetic variability and belonged to clade I, possibly originating from BJ004-H7 in Beijing. All 35 isolates were resistant to Fluconazole (FCZ) and amphotericin B (AMB), and 3 isolates were resistant to caspofungin (CAS). Mutations in ERG11 and FKS1 were linked to reduced azole and echinocandin susceptibility, respectively.

CONCLUSIONS

Two outbreaks of highly clonal, multidrug-resistant C. auris isolates within the medical facility were reported. The intensive performance of disinfection measures helped block in-hospital transmission. Understanding the epidemiology, drug resistance and management of C. auris will be helpful for implementing effective infection control and treatment strategies.

Mapping of the Lipid-Binding Regions of the Antifungal Protein NFAP2 by Exploiting Model Membranes

Fungal infections with high mortality rates represent an increasing health risk. The Neosartorya (Aspergillus) fischeri antifungal protein 2 (NFAP2) is a small, cysteine-rich, cationic protein exhibiting potent anti-Candida activity. As the underlying mechanism, pore formation has been demonstrated; however, molecular level details on its membrane disruption action are lacking. Herein, we addressed the lipid binding of NFAP2 using a combined computational and experimental approach to simple lipid compositions with various surface charge properties. Simulation results revealed binding preferences for negatively charged model membranes, where selectivity is mediated by anionic lipid components enriched at the protein binding site but also assisted by zwitterionic lipid species. Several potential binding routes initiated by various anchoring contacts were observed, which resulted in one main binding mode and a few variants, with NFAP2 residing on the membrane surface. Region 10NCPNNCKHKKG20 of the flexible N-terminal part of the protein showed potency to insert into the lipid bilayer, where the disulfide bond-stabilized short motif 11CPNNC15 could play a key role. In addition, several areas, including the beginning of the N-terminal (residues 1-8), played roles in facilitating initial membrane contacts. Besides, individual roles of residues such as Lys24, Lys32, Lys34, and Trp42 were also revealed by the simulations. Combined data demonstrated that the solution conformation was not perturbed markedly upon membrane interaction, and the folded part of the protein also contributed to stabilizing the bound state. Data also highlighted that the binding of NFAP2 to lipid vesicles is sensitively affected by environmental factors such as ionic strength. Electrostatic interactions driven by anionic lipids were found pivotal, explaining the reduced membrane activity observed under high salt conditions. Experimental data supported the lipid-selective binding mechanisms and pointed to salt-dependent effects, particularly to protein-assisted vesicle aggregation at low ionic strength. Our findings can contribute to the development of NFAP2-based anti-Candida agents and studies aiming at future medical use of peptide-based natural antifungal compounds.

Antifungal activity of tannic acid against Candida spp. and its mechanism of action

The increase in fungal resistance is a major public health concern. In this context, Candida spp. is an important genus related to invasive diseases, especially in immunosuppressed patients. The relevance of alternative approaches to increasing fungal resistance stands out, in which products of natural origin demonstrate potential antifungal activity in vitro against Candida spp. In this sense, this work aimed to evaluate the in vitro activity of tannic acid against Candida spp. Minimum inhibitory concentration (MIC) was determined for tannic acid and the antifungals, and the checkerboard assay was performed to analyze the interactions between them. Furthermore, we evaluated the tannic acid antibiofilm activity and its possible mechanism of action. Tannic acid showed MIC ranging to 0.06 to 0.5 µg/ml and showed no loss of effectiveness when combined with antifungals. Also, is safe at the concentrations it exerts its antifungal activity in pre-formed biofilms, as demonstrated by IC50 in murine fibroblasts cells and the hemolytic assay. Additionally, its mechanisms of action can be related with induction of signals that lead to apoptosis in fungal cells.

Association of oral fungal profiles with health status and bacterial composition in elderly adults receiving community support and home care service

Fungi compose a minority but a common component of normal oral microbiota and contribute to oral and systemic health by interacting with bacterial inhabitants. This study investigated the relationship of oral fungal profiles to health status and bacterial profiles of 159 elderly adults receiving community support and home care services. Fungal and bacterial densities and compositions were determined based on the fungal ribosomal internal transcribed spacer region and bacterial 16S rRNA gene amplicon analyses, respectively. The total fungal density of 87 individuals exceeded 5,000 copies, and their microbiota was characterized by significantly less dense bacterial populations and lower relative abundances of oral health-associated taxa, such as Neisseria perflava and Porphyromonas pasteri, compared with those with less than 5,000 copies of fungi. These individuals were significantly older, had fewer teeth, had lower physical function, and comprised more denture users and individuals with cognitive decline. Fungal compositions were classified into three profiles (Candida albicans-dominant, non-albicans Candida-dominant, and non-Candida-dominant), and individuals with a non-albicans Candida-dominant profile exhibited significantly lower physical and cognitive function than those with the Candida albicans-dominant profile. These results demonstrate that a high-density fungal population co-occurs with poor oral and systemic health status of the host and dysbiosis of the bacterial community, and particularly, the overgrowth of non-albicans Candida species may be implicated in worsening systemic conditions.

IMPORTANCE

The interaction between fungal and bacterial components involved in the virulence of oral microbiota has received attention. This study demonstrates that an increase in fungal components is associated with a dysbiotic bacterial community and poor health status in elderly adults. Among individuals with a high-density fungal population, particularly, those with a non-albicans Candida-dominant profile had lower physical and cognitive functions than those with a C. albicans-dominant profile. These findings indicate that the evaluation of fungal components, in addition to the bacterial components, is important to understand the involvement of oral microbiota in oral and systemic diseases in elderly adults.