The global problem of antifungal resistance: prevalence, mechanisms, and management

Potential antifungal applications of heterometallic silica nanohybrids: A synergistic activity

An estimated 1.7 million fatalities and 150 million cases worldwide are attributed to fungal infections annually, that are in rise due to immunocompromised patient population. The challenges posed by traditional treatments can be addressed with the help of nanotechnology advancements. In this study, Co, Cu, and Ag-were doped into silica nanoparticles. Then the synthesized monometallic silica nanohybrids were combined to formulate heterometallic silica nanohybrids, characterized structurally and morphologically, compared, and evaluated for antifungal activity based on their individual and synergistic activity. The antifungal assays were conducted by using ATCC cultures of Candida albicans and QC samples of Trichophyton rubrum, Microsporum gypseum, and Aspergillus niger. The MIC (ranging from 49.00 to 1560.00 μg/mL), MFC (ranging from 197.00 to 3125.00 μg/mL), IC50 values (ranging from 31.10 to 400.80 μg/mL), and FICI of nanohybrids were determined and compared. Moreover, well diffusion assay was performed. ABTS assay and DPPH assay were conducted to investigate the radical scavenging activity (RSA) of nanohybrids. SEM analysis clearly evidenced the structural deformations of each fungal cells and spores due to the treatment with trimetallic nanohybrid. According to the results, the trimetallic silica nanohybrids exhibited the most powerful synergistic RSA and the most effective antifungal activity, compared to the bimetallic silica nanohybrids.

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.

Effect of disinfectants on multispecies biofilm, the physical and mechanical properties of polymethyl methacrylate, and the corrosion of cobalt chromium alloy

STATEMENT OF PROBLEM

The optimal disinfection protocol that controls adverse effects and promotes effective antimicrobial action on removable prostheses is unclear.

PURPOSE

This in vitro study investigated the effect of disinfectant solutions on the biological, physical, mechanical, and chemical properties of removable prosthesis materials.

MATERIAL AND METHODS

Specimens of polymethyl methacrylate (PMMA) and cobalt chromium (Co-Cr) alloy were immersed in distilled water (PMMA) or artificial saliva (Co-Cr) as the control and in 0.25% sodium hypochlorite (NaOCl0.25%), 0.5% chloramine T (CT0.5%), and 0.15% Triclosan (TR0.15%). The antibiofilm activity was evaluated by microbial load and cell metabolisms of the mixed biofilm. Physical (color change, sorption, solubility, and surface roughness), mechanical (hardness, flexural, and impact strength), and chemical (corrosion) properties were analyzed before and after simulating a 5-year immersion. Laser confocal microscopy, scanning electron microscopy (SEM), and dispersive energy spectroscopy (EDS) complemented the analyses. The data were analyzed by using the Mann-Whitney U test, Kruskal-Wallis with Dunn posttests, 1-way ANOVA, and repeated measures ANOVA (α=.05).

RESULTS

All solutions were effective against bacteria, but only NaOCl0.25% eliminated Candida spp. TR0.15%, and CT0.5% increased cell metabolisms. For interaction (time and solution), there was a reduction in PMMA hardness in the control and TR0.15%. Color, sorption, solubility, and flexural strength did not change. CT0.5% and TR0.15% were similar for impact resistance. CT0.5% caused the lowest roughness. NaOCl0.25% showed the greatest corrosive potential. Dark spots were seen under SEM in Co-Cr stored with NaOCl0.25% and TR0.15%. EDS indicated different proportions of oxygen, cobalt, chromium, and molybdenum.

CONCLUSIONS

NaOCl0.25% had the best antimicrobial action. CT0.5% and TR0.15% have potential. Hardness and roughness changes were clinically acceptable, and the other properties remained unchanged. All the solutions caused color changes. NaOCl0.25% was unsatisfactory for use with Co-Cr, CT0.5% was intermediate, and TR0.15% was suitable.

Synthesis and characterization of new acid-functionalized porphyrins displaying antimicrobial activity against gram positive bacteria, yeasts and filamentous fungi with or without ultra-high irradiance

The antimicrobial activity of new acid-functionalized porphyrins, with or without ultra-high irradiance, was investigated. Antibacterial efficacy was evaluated against Staphylococcus aureus (methicillin-resistant or methicillin-sensitive strains) and antifungal efficacy was evaluated against the yeast Candida albicans and the filamentous fungi Aspergillus fumigatus. Overall, the porphyrins tested are more effective against S. aureus. The best results were obtained with zinc diacid porphyrins 4 and 5 after only 3 min of ultra-high irradiation (500 mW/cm2, 405 nm), demonstrating that acid-functionalized porphyrins are promising as novel antimicrobial drugs for surface disinfection.

Candida lusitaniae Fungemia in Children: A multicenter case series of emerging pathogen

Candida lusitaniae fungemia is a serious infection that is rarely reported in children. The aim of this study is to describe a case series of C. lusitaniae fungemia and review previous publications regarding this rare pathogen. This is a multicenter case series of children diagnosed with C. lusitaniae fungemia. A total of 18 cases that occurred over a 15-year period in five tertiary hospitals were included. Additionally, a review of the literature regarding C. lusitaniae fungemia in children was performed. A total of 18 cases were enrolled; 11/18 (61%) were males, with a mean age of 2.3 years. All patients had severe underlying diseases and risk factors for opportunistic infection, most commonly prematurity and malignancies. More than one-third of cases occurred during the last 2 years of the study period. All isolates were susceptible to all tested antifungals. The survival rate following the acute infection was 94%, whereas the survival rate of 14 previously published cases was 71%, with the most common underlying diseases being CGD and malignancies. Candida lusitaniae fungemia is not a common event in the pediatric population, occurring exclusively in children with severe underlying diseases and significant risk factors. This cohort revealed better clinical outcomes than previously reported. All tested isolates were susceptible to all antifungal agents; variability in susceptibility as previously reported was not found in this study. The allegedly higher rate of infection in recent years is in need of further investigation in larger prospective studies in order to conclude if a real trend is at play.

Response of Fusarium oxysporum soil isolate to amphotericin B and fluconazole at the proteomic level

Fusarium oxysporum is a cross-kingdom pathogen that infects humans, animals, and plants. The primary concern regarding this genus revolves around its resistance profile to multiple classes of antifungals, particularly azoles. However, the resistance mechanism employed by Fusarium spp. is not fully understood, thus necessitating further studies to enhance our understanding and to guide future research towards identifying new drug targets. Here, we employed an untargeted proteomic approach to assess the differentially expressed proteins in a soil isolate of Fusarium oxysporum URM7401 cultivated in the presence of amphotericin B and fluconazole. In response to antifungals, URM7401 activated diverse interconnected pathways, such as proteins involved in oxidative stress response, proteolysis, and lipid metabolism. Efflux proteins, antioxidative enzymes and M35 metallopeptidase were highly expressed under amphotericin B exposure. Antioxidant proteins acting on toxic lipids, along with proteins involved in lipid metabolism, were expressed during fluconazole exposure. In summary, this work describes the protein profile of a resistant Fusarium oxysporum soil isolate exposed to medical antifungals, paving the way for further targeted research and discovering new drug targets.

Emerging trends of invasive yeast infections and azole resistance in Beijing intensive care units

BACKGROUND

Invasive fungal infections pose a substantial threat to patients in healthcare settings globally. Recent changes in the prevalence of fungal species and challenges in conducting reference antifungal susceptibility testing emphasize the importance of monitoring fungi and their antifungal resistance.

METHODS

A two-phase surveillance project was conducted in Beijing, China, involving 37 centres across 12 districts, from January 2012 to December 2013 and from January 2016 to December 2017.

FINDINGS

We found that the proportion of Candida albicans in intensive care units (ICUs) during 2016-2017 exhibited a significant decline compared with the 2012-2013 period, although it remained the most predominant pathogen. In contrast, the prevalence of Nakaseomyces glabratus (formerly Candida glabrata) and Candida tropicalis notably increased during the two-phase surveillance. The high prevalence of C. tropicalis and its resistance to azole drugs posed a serious threat to patients in ICUs. The pathogens causing invasive fungal infections in Beijing were relatively sensitive to echinocandins. While C. albicans continued to exhibit susceptibility to azoles, the resistance and growth rates of C. tropicalis towards azoles were particularly prominent. Concerns were raised due to the emergence of multiple, short-term isolates of Clavispora lusitaniae and Candida parapsilosis complex in neonatal ICUs, given their similarity in antifungal susceptibilities. Such occurrences point towards the potential for transmission and persisting presence of these pathogens within the ICU environment.

CONCLUSIONS

Our study complements existing data on the epidemiology of invasive fungal infections. It is imperative to exercise cautious medication management for ICU patients in Beijing, paying particular attention to azole resistance in C. tropicalis.

Pan-drug resistance and hypervirulence in a human fungal pathogen are enabled by mutagenesis induced by mammalian body temperature

The continuing emergence of invasive fungal pathogens poses an increasing threat to public health. Here, through the China Hospital Invasive Fungal Surveillance Net programme, we identified two independent cases of human infection with a previously undescribed invasive fungal pathogen, Rhodosporidiobolus fluvialis, from a genus in which many species are highly resistant to fluconazole and caspofungin. We demonstrate that R. fluvialis can undergo yeast-to-pseudohyphal transition and that pseudohyphal growth enhances its virulence, revealed by the development of a mouse model. Furthermore, we show that mouse infection or mammalian body temperature induces its mutagenesis, allowing the emergence of hypervirulent mutants favouring pseudohyphal growth. Temperature-induced mutagenesis can also elicit the development of pan-resistance to three of the most commonly used first-line antifungals (fluconazole, caspofungin and amphotericin B) in different Rhodosporidiobolus species. Furthermore, polymyxin B was found to exhibit potent activity against the pan-resistant Rhodosporidiobolus mutants. Collectively, by identifying and characterizing a fungal pathogen in the drug-resistant genus Rhodosporidiobolus, we provide evidence that temperature-dependent mutagenesis can enable the development of pan-drug resistance and hypervirulence in fungi, and support the idea that global warming can promote the evolution of new fungal pathogens.

Genotypic diversity, virulence, and molecular genetic tools in Histoplasma

SUMMARYHistoplasmosis is arguably the most common fungal respiratory infection worldwide, with hundreds of thousands of new infections occurring annually in the United States alone. The infection can progress in the lung or disseminate to visceral organs and can be difficult to treat with antifungal drugs. Histoplasma, the causative agent of the disease, is a pathogenic fungus that causes life-threatening lung infections and is globally distributed. The fungus has the ability to germinate from conidia into either hyphal (mold) or yeast form, depending on the environmental temperature. This transition also regulates virulence. Histoplasma and histoplasmosis have been classified as being of emergent importance, and in 2022, the World Health Organization included Histoplasma as 1 of the 19 most concerning human fungal pathogens. In this review, we synthesize the current understanding of the ecological niche, evolutionary history, and virulence strategies of Histoplasma. We also describe general patterns of the symptomatology and epidemiology of histoplasmosis. We underscore areas where research is sorely needed and highlight research avenues that have been productive.

Aspergillus fumigatus-a systematic review to inform the World Health Organization priority list of fungal pathogens

Recognizing the growing global burden of fungal infections, the World Health Organization established a process to develop a priority list of fungal pathogens (FPPL). In this systematic review, we aimed to evaluate the epidemiology and impact of invasive infections caused by Aspergillus fumigatus to inform the first FPPL. The pre-specified criteria of mortality, inpatient care, complications and sequelae, antifungal susceptibility, risk factors, preventability, annual incidence, global distribution, and emergence were used to search for relevant articles between 1 January 2016 and 10 June 2021. Overall, 49 studies were eligible for inclusion. Azole antifungal susceptibility varied according to geographical regions. Voriconazole susceptibility rates of 22.2% were reported from the Netherlands, whereas in Brazil, Korea, India, China, and the UK, voriconazole susceptibility rates were 76%, 94.7%, 96.9%, 98.6%, and 99.7%, respectively. Cross-resistance was common with 85%, 92.8%, and 100% of voriconazole-resistant A. fumigatus isolates also resistant to itraconazole, posaconazole, and isavuconazole, respectively. The incidence of invasive aspergillosis (IA) in patients with acute leukemia was estimated at 5.84/100 patients. Six-week mortality rates in IA cases ranged from 31% to 36%. Azole resistance and hematological malignancy were poor prognostic factors. Twelve-week mortality rates were significantly higher in voriconazole-resistant than in voriconazole-susceptible IA cases (12/22 [54.5%] vs. 27/88 [30.7%]; P = .035), and hematology patients with IA had significantly higher mortality rates compared with solid-malignancy cases who had IA (65/217 [30%] vs. 14/78 [18%]; P = .04). Carefully designed surveillance studies linking laboratory and clinical data are required to better inform future FPPL.

Targeting dermatophyte Cdc42 and Rac GTPase signaling to hinder hyphal elongation and virulence

The development of antifungal drugs requires novel molecular targets due to limited treatment options and drug resistance. Through chemical screening and establishment of a novel genetic technique to repress gene expression in Trichophyton rubrum, the primary causal fungus of dermatophytosis, we demonstrated that fungal Cdc42 and Rac GTPases are promising antifungal drug targets. Chemical inhibitors of these GTPases impair hyphal formation, which is crucial for growth and virulence in T. rubrum. Conditional repression of Cdc24, a guanine nucleotide exchange factor for Cdc42 and Rac, led to hyphal growth defects, abnormal cell morphology, and cell death. EHop-016 inhibited the promotion of the guanine nucleotide exchange reaction in Cdc42 and Rac by Cdc24 as well as germination and growth on the nail fragments of T. rubrum and improved animal survival in an invertebrate infection model of T. rubrum. Our results provide a novel antifungal therapeutic target and a potential lead compound.

Clinical and epidemiological aspects of Candida yeast infections and rational use of antifungals

Aim: The objective of this study was to evaluate the clinical and epidemiological aspects of Candida infections. Methods: The study relied on the analysis of electronic medical records. Results: Among 183 patients with positive fungal infections, 57 were from the community and 126 from hospitals. Females predominated in both groups (82.4% in the community, 54.7% in hospitals). Non-albicans Candida spp. accounted for 62.8% of cases. Antifungal therapy was prescribed for 67 patients, with a 55.6% mortality rate. Conclusion: The increasing prevalence of non-albicans Candida species highlights the need for better candidiasis monitoring and control, especially concerning antifungal use amidst rising antimicrobial resistance, particularly in empirical therapy scenarios.

Azole resistance in Aspergillus fumigatus- comprehensive review

Aspergillus fumigatus is a ubiquitous filamentous fungus commonly found in the environment. It is also an opportunistic human pathogen known to cause a range of respiratory infections, such as invasive aspergillosis, particularly in immunocompromised individuals. Azole antifungal agents are widely used for the treatment and prophylaxis of Aspergillus infections due to their efficacy and tolerability. However, the emergence of azole resistance in A. fumigatus has become a major concern in recent years due to their association with increased treatment failures and mortality rates. The development of azole resistance in A. fumigatus can occur through both acquired and intrinsic mechanisms. Acquired resistance typically arises from mutations in the target enzyme, lanosterol 14-α-demethylase (Cyp51A), reduces the affinity of azole antifungal agents for the enzyme, rendering them less effective, while intrinsic resistance refers to a natural resistance of certain A. fumigatus isolates to azole antifungals due to inherent genetic characteristics. The current review aims to provide a comprehensive overview of azole antifungal resistance in A. fumigatus, discusses underlying resistance mechanisms, including alterations in the target enzyme, Cyp51A, and the involvement of efflux pumps in drug efflux. Impact of azole fungicide uses in the environment and the spread of resistant strains is also explored.

Sirtuin E deacetylase is required for full virulence of Aspergillus fumigatus

Aspergillus fumigatus represents a public health problem due to the high mortality rate in immunosuppressed patients and the emergence of antifungal-resistant isolates. Protein acetylation is a crucial post-translational modification that controls gene expression and biological processes. The strategic manipulation of enzymes involved in protein acetylation has emerged as a promising therapeutic approach for addressing fungal infections. Sirtuins, NAD+-dependent lysine deacetylases, regulate protein acetylation and gene expression in eukaryotes. However, their role in the human pathogenic fungus A. fumigatus remains unclear. This study constructs six single knockout strains of A. fumigatus and a strain lacking all predicted sirtuins (SIRTKO). The mutant strains are viable under laboratory conditions, indicating that sirtuins are not essential genes. Phenotypic assays suggest sirtuins' involvement in cell wall integrity, secondary metabolite production, thermotolerance, and virulence. Deletion of sirE attenuates virulence in murine and Galleria mellonella infection models. The absence of SirE alters the acetylation status of proteins, including histones and non-histones, and triggers significant changes in the expression of genes associated with secondary metabolism, cell wall biosynthesis, and virulence factors. These findings encourage testing sirtuin inhibitors as potential therapeutic strategies to combat A. fumigatus infections or in combination therapy with available antifungals.

Novel aza-bicyclic 2-isoxazoline acylhydrazone hybrids and their synergistic potential with fluconazole against a drug-resistant Candida albicans strain

As the prevalence of drug-resistant Candida isolates continues to rise, the imperative for identifying novel compounds to enhance the arsenal of antifungal drugs becomes increasingly critical. Consequently, exploring new treatment strategies, including synthesizing molecular hybrids and applying combination therapy, is essential. For this reason, this study evaluated the efficacy of ten molecular hybrids of aza-bicyclic 2-isoxazoline-acylhydrazone belonging to two series 90 and 91 as possible anti-Candida agents. In addition, we also investigated the interaction between the hybrids and fluconazole, a commonly used antifungal drug. We evaluated the antifungal effect of aza-bicyclic 2-isoxazoline-acylhydrazone hybrid compounds against six Candida spp. strains that target planktonic cells. However, none of these new molecules were inhibitory active at the tested concentrations (2 to 1,024 µg/mL). Moreover, we analyzed the interaction between the ten new hybrid molecules and fluconazole using the checkerboard assay, employing two different methodologies for reading the plate. For this, one isolate fluconazole-resistant was selected. We observed that only one combination, 6-(4-tert-butylbenzoil)-4,5,6,6a-tetrahydro-3a-H-pirrole[3,2-d]isoxazole-3-carboxylic(furan-2-metilidene)-hydrazide (91e) and fluconazole, exhibited a synergistic interaction (FICI range 0.0781 to 0.4739). The combination successfully inhibited the growth of C. albicans CA2 fluconazole-resistant, and no interaction was observed in an isolate susceptible to fluconazole. Additionally, these results emphasize the continued need for research into new compounds and the importance of using combined approaches to increase their activity.

Candida glabrata hospital isolate from Lebanon reveals micafungin resistance associated with increased chitin and resistance to a cell-surface-disrupting agent

OBJECTIVES

This study aimed to identify the resistance mechanisms to micafungin and fluconazole in a clinical isolate of Candida glabrata.

METHODS

The isolate was whole-genome sequenced to identify amino acid changes in key proteins involved in antifungal resistance, and the isolate was further characterised by pathogenicity-related phenotypic assays that supported the sequencing results.

RESULTS

Amino acid substitutions were detected in 8 of 17 protein candidates. Many of these substitutions were novel, including in CHS3, CHS3B, and KRE5, which are involved in the development of micafungin resistance. Regarding fluconazole resistance, overexpression of efflux pumps was observed. Our isolate did not exhibit an increased virulence potential compared with the control strain; however, a significant increase in chitin content and potential to resist the cell surface disruptant sodium dodecyl sulphate was observed.

CONCLUSIONS

This clinical Candida glabrata isolate experienced a change in cell wall architecture, which correlates with the development of micafungin resistance.

Rapid identification,fluconazole and micafungin susceptibility testing of Candida species from blood culture by a short incubation method

This study aimed to develop and validate a rapid method for identification by MALDI-TOF system and determination of the susceptibility to Fluconazole and Micafungin by broth microdilution among Candidaspecies causing bloodstream infections. Subcultures from blood culture bottles were incubated for 5 hours (+/- 1h) and used to perform the tests, so that the turnaround time of rapid identification and susceptibility profile was about 5 and 24 hours, respectively. The rapid identification showed agreement of 92.05 %. Regarding the rapid broth microdilution for Fluconazole and Micafungin, the agreement was 97.06 % (p<0.001) and 100 % (p<0.001), and the Kappa coefficient was 0.91 (p<0.001) and 1.0 (p<0.001), respectively. To conclude, both rapid methods showed to be reproducible, inexpensive, easy to perform and time-saving. Thus, these methodologies could be useful to guide and adjust empirical antifungal therapy.

Holotoxin A1 from Apostichopus japonicus inhibited oropharyngeal and intra-abdominal candidiasis by inducing oxidative damage in Candida albicans

BACKGROUND AND PURPOSE

The holotoxin A1, isolated from Apostichopus japonicus, exhibits potent antifungal activities, but the mechanism and efficacy against candidiasis are unclear. In this study we have studied the antifungal effects and mechanism of holotoxin A1 against Candida albicans and in murine oropharyngeal and intra-abdominal candidiasis.

EXPERIMENTAL APPROACH

The antifungal effect of holotoxin A1 against C. albicans was tested in vitro. To explore the antifungal mechanism of holotoxin A1, the transcriptome, ROS levels, and mitochondrial function of C. albicans was evaluated. Effectiveness and systematic toxicity of holotoxin A1 in vivo was assessed in the oropharyngeal and intra-abdominal candidiasis models in mice.

KEY RESULTS

Holotoxin A1 was a potent fungicide against C. albicans SC5314, clinical strains and drug-resistant strains. Holotoxin A1 inhibited oxidative phosphorylation and induced oxidative damage by increasing intracellular accumulation of ROS in C. albicans. Holotoxin A1 induced dysfunction of mitochondria by depolarizing the mitochondrial membrane potential and reducing the production of ATP. Holotoxin A1 directly inhibited the enzymatic activity of mitochondrial complex I and antagonized with the rotenone, an inhibitor of complex I, against C. albicans. Meanwhile, the complex I subunit NDH51 null mutants showed a decreased susceptibility to holotoxin A1. Furthermore, holotoxin A1 significantly reduced fungal burden and infections with no significant systemic toxicity in oropharyngeal and intra-abdominal candidiasis in murine models.

CONCLUSION AND IMPLICATIONS

Holotoxin A1 is a promising candidate for the development of novel antifungal agents against both oropharyngeal and intra-abdominal candidiasis, especially when caused by drug-resistant strains.

Drug-resistant oral candidiasis in patients with HIV infection: a systematic review and meta-analysis

BACKGROUND

Oral candidiasis (OC) is a prevalent opportunistic infection in patients with human immunodeficiency virus (HIV) infection. The increasing resistance to antifungal agents in HIV-positive individuals suffering from OC raised concerns. Thus, this study aimed to investigate the prevalence of drug-resistant OC in HIV-positive patients.

METHODS

Pubmed, Web of Science, Scopus, and Embase databases were systematically searched for eligible articles up to November 30, 2023. Studies reporting resistance to antifungal agents in Candida species isolated from HIV-positive patients with OC were included. Baseline characteristics, clinical features, isolated Candida species, and antifungal resistance were independently extracted by two reviewers. The pooled prevalence with a 95% confidence interval (CI) was calculated using the random effect model or fixed effect model.

RESULTS

Out of the 1942 records, 25 studies consisting of 2564 Candida species entered the meta-analysis. The pooled prevalence of resistance to the antifungal agents was as follows: ketoconazole (25.5%, 95% CI: 15.1-35.8%), fluconazole (24.8%, 95% CI: 17.4-32.1%), 5-Flucytosine (22.9%, 95% CI: -13.7-59.6%), itraconazole (20.0%, 95% CI: 10.0-26.0%), voriconazole (20.0%, 95% CI: 1.9-38.0%), miconazole (15.0%, 95% CI: 5.1-26.0%), clotrimazole (13.4%, 95% CI: 2.3-24.5%), nystatin (4.9%, 95% CI: -0.05-10.3%), amphotericin B (2.9%, 95% CI: 0.5-5.3%), and caspofungin (0.1%, 95% CI: -0.3-0.6%). Furthermore, there were high heterogeneities among almost all included studies regarding the resistance to different antifungal agents (I2 > 50.00%, P < 0.01), except for caspofungin (I2 = 0.00%, P = 0.65).

CONCLUSIONS

Our research revealed that a significant number of Candida species found in HIV-positive patients with OC were resistant to azoles and 5-fluocytosine. However, most of the isolates were susceptible to nystatin, amphotericin B, and caspofungin. This suggests that initial treatments for OC, such as azoles, may not be effective. In such cases, healthcare providers may need to consider prescribing alternative treatments like polyenes and caspofungin.

REGISTRATION

The study protocol was registered in the International Prospective Register of Systematic Reviews as PROSPERO (Number: CRD42024497963).

Advancements in nanoparticle-based therapies for multidrug-resistant candidiasis infections: a comprehensive review

Candida auris, a rapidly emerging multidrug-resistant fungal pathogen, poses a global health threat, with cases reported in over 47 countries. Conventional detection methods struggle, and the increasing resistance ofC. auristo antifungal agents has limited treatment options. Nanoparticle-based therapies, utilizing materials like silver, carbon, zinc oxide, titanium dioxide, polymer, and gold, show promise in effectively treating cutaneous candidiasis. This review explores recent advancements in nanoparticle-based therapies, emphasizing their potential to revolutionize antifungal therapy, particularly in combatingC. aurisinfections. The discussion delves into mechanisms of action, combinations of nanomaterials, and their application against multidrug-resistant fungal pathogens, offering exciting prospects for improved clinical outcomes and reduced mortality rates. The aim is to inspire further research, ushering in a new era in the fight against multidrug-resistant fungal infections, paving the way for more effective and targeted therapeutic interventions.

Pitavastatin Calcium Confers Fungicidal Properties to Fluconazole by Inhibiting Ubiquinone Biosynthesis and Generating Reactive Oxygen Species

Fluconazole (FLC) is extensively employed for the prophylaxis and treatment of invasive fungal infections (IFIs). However, the fungistatic nature of FLC renders pathogenic fungi capable of developing tolerance towards it. Consequently, converting FLC into a fungicidal agent using adjuvants assumes significance to circumvent FLC resistance and the perpetuation of fungal infections. This drug repurposing study has successfully identified pitavastatin calcium (PIT) as a promising adjuvant for enhancing the fungicidal activity of FLC from a comprehensive library of 2372 FDA-approved drugs. PIT could render FLC fungicidal even at concentrations as low as 1 μM. The median lethal dose (LD50) of PIT was determined to be 103.6 mg/kg. We have discovered that PIT achieves its synergistic effect by inhibiting the activity of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, thereby impeding ubiquinone biosynthesis, inducing reactive oxygen species (ROS) generation, triggering apoptosis, and disrupting Golgi function. We employed a Candida albicans strain that demonstrated a notable tolerance to FLC to infect mice and found that PIT effectively augmented the antifungal efficacy of FLC against IFIs. This study is an illustrative example of how FDA-approved drugs can effectively eliminate fungal tolerance to FLC.

In Silico and In Vitro Evaluation of the Antifungal Activity of a New Chromone Derivative against Candida spp

Candida species are frequently implicated in the development of both superficial and invasive fungal infections, which can impact vital organs. In the quest for novel strategies to combat fungal infections, there has been growing interest in exploring synthetic and semi-synthetic products, particularly chromone derivatives, renowned for their antimicrobial properties. In the analysis of the antifungal activity of the compound (E)-benzylidene-chroman-4-one against Candida, in silico and laboratory tests were performed to predict possible mechanisms of action pathways, and in vitro tests were performed to determine antifungal activity (MIC and MFC), to verify potential modes of action on the fungal cell membrane and wall, and to assess cytotoxicity in human keratinocytes. The tested compound exhibited predicted affinity for all fungal targets, with the highest predicted affinity observed for thymidylate synthase (-102.589 kJ/mol). MIC and CFM values ranged from 264.52 μM (62.5 μg/mL) to 4232.44 μM (1000 μg/mL). The antifungal effect likely occurs due to the action of the compound on the plasma membrane. Therefore, (E)-benzylidene-chroman-4-one showed fungicidal-like activity against Candida spp., possibly targeting the plasma membrane.

Carbon substrates promotes stress resistance and drug tolerance in clinical isolates of Candida tropicalis

Candida tropicalis is a human pathogen and one of the most prevalent non-Candida albicans Candida (NCAC) species causing invasive infections. Azole antifungal resistance in C. tropicalis is also gradually increasing with the increasing incidence of infections. The pathogenic success of C. tropicalis depends on its effective response in the host microenvironment. To become a successful pathogen, cellular metabolism, and physiological status determine the ability of the pathogen to counter diverse stresses inside the host. However, to date, limited knowledge is available on the impact of carbon substrate metabolism on stress adaptation and azole resistance in C. tropicalis. In this study, we determined the impact of glucose, fructose, and sucrose as the sole carbon source on the fluconazole resistance and osmotic (NaCl), oxidative (H2O2) stress adaptation in C. tropicalis clinical isolates. We confirmed that the abundance of carbon substrates influences or increases drug resistance and osmotic and oxidative stress tolerance in C. tropicalis. Additionally, both azole-resistant and susceptible isolates showed similar stress adaptation phenotypes, confirming the equal efficiency of becoming successful pathogens irrespective of drug susceptibility profile. To the best of our knowledge, our study is the first on C. tropicalis to demonstrate the direct relation between carbon substrate metabolism and stress tolerance or drug resistance.

Exposure to resistant fungi across working environments and time

Antifungal resistance has emerged as a significant health concern with increasing reports of resistant variants in previously susceptible species. At present, little is known about occupational exposure to antifungal-resistant fungi. This study aimed to investigate Danish workers' occupational exposure to airborne fungi resistant to first-line treatment drugs. A retrospective study was performed on a unique collection of personal exposure samples gathered over a twenty-year period from Danish working environments, in sectors including agriculture, animal handling, waste management, and healthcare. A total of 669 samples were cultivated at 37 °C and fungal colonies were identified using MALDI-TOF MS. Subsequently, identification was confirmed by amplicon sequencing the genes of calmodulin and beta-tubulin to unveil potential cryptic species. Infectious fungi (495 isolates from 23 species) were tested for resistance against Itraconazole, Voriconazole, Posaconazole, and Amphotericin B. Working environments were highly variable in the overall fungal exposure, and showed vastly different species compositions. Resistance was found in 30 isolates of the species Aspergillus fumigatus (4 of 251 isolates), A. nidulans (2 of 13), A. niger complex (19 of 131), A. versicolor (3 of 18), and A. lentulus (2 of 2). Sequence analysis revealed several cryptic species within the A. niger complex including A. tubingensis, A. luchuensis, and A. phoenicis. Among the resistant A. fumigatus isolates, two contained the well-described TR34/L98H mutation in the cyp51A gene and promoter region, while the remainder harbored silent mutations. The results indicate that the working environment significantly contributes to exposure to resistant fungi, with particularly biofuel plant workers experiencing high exposure. Differences in the prevalence of resistance across working environments may be linked to the underlying species composition.

Anti-Candida activity and in vitro toxicity screening of antifungals complexed with β-cyclodextrin

The emergence of resistant fungal species and the toxicity of currently available antifungal drugs are relevant issues that require special consideration. Cyclodextrins inclusion complexes could optimize the antimicrobial activity of such drugs and create a controlled release system with few side effects. This study aimed to assess the in vitro toxicity and antifungal effectiveness of nystatin (Nys) and chlorhexidine (Chx) complexed or not with β-cyclodextrin (βCD). First, a drug toxicity screening was performed through the Artemia salina bioassay. Then, the minimum inhibitory concentrations (MICs) against Candida albicans were determined with the broth microdilution test. After MICs determination, the cytotoxicity of the drugs was evaluated through the methyl-thiazolyl-tetrazolium (MTT) and neutral red (NR) assays and through cell morphology analysis. The PROBIT analysis was used to determine the median lethal concentration (LC50), and the cell viability values were submitted to one-way analysis of variance(ANOVA)/Tukey (α = 0.05). Overall, the βCD-complexed antifungals were less toxic against A. salina than their raw forms, suggesting that inclusion complexes can reduce the toxicity of drugs. The MICs obtained were as follows: Nys 0.5 mg/L; Nys:βCD 4 mg/L; Chx 4 mg/L; and Chx:βCD 8 mg/L. Chx showed significant cytotoxicity (MTT: 12.9 ± 9.6%; NR: 10.6 ± 12.5%) and promoted important morphological changes. Cells exposed to the other drugs showed viability above 70% with no cellular damage. These results suggest that antifungals complexed with βCD might be a biocompatible option for the treatment of Candida-related infections.

Inferring fungal growth rates from optical density data

Quantifying fungal growth underpins our ability to effectively treat severe fungal infections. Current methods quantify fungal growth rates from time-course morphology-specific data, such as hyphal length data. However, automated large-scale collection of such data lies beyond the scope of most clinical microbiology laboratories. In this paper, we propose a mathematical model of fungal growth to estimate morphology-specific growth rates from easy-to-collect, but indirect, optical density (OD600) data of Aspergillus fumigatus growth (filamentous fungus). Our method accounts for OD600 being an indirect measure by explicitly including the relationship between the indirect OD600 measurements and the calibrating true fungal growth in the model. Therefore, the method does not require de novo generation of calibration data. Our model outperformed reference models at fitting to and predicting OD600 growth curves and overcame observed discrepancies between morphology-specific rates inferred from OD600 versus directly measured data in reference models that did not include calibration.

Impact of Nitric Oxide-Release Kinetics on Antifungal Activity

Pathogenic fungi are an increasing health threat due to the rise in drug resistance. The limited number of antifungals currently available and growing incidence of multi-drug-resistant fungi has caused rising healthcare costs and a decreased quality of life for patients with fungal infections. Nitric oxide (NO) has previously been shown to act as an antimicrobial agent, albeit with a limited understanding of the effects of the NO-release kinetics against pathogenic fungi. Herein, the antifungal effects of four nitric oxide-releasing small molecules were studied against the pathogenic fungi Candida albicans, Candida auris, Cryptococcus neoformans, and Aspergillus fumigatus, to demonstrate the broad-spectrum antifungal activity of NO. A bolus dose of NO was found to eradicate fungi after 24 h, where nitric oxide donors with shorter half-lives achieved antifungal activity at lower concentrations and thus had wider selectivity indexes. Each NO donor was found to cause a severe surface destruction of fungi, and all NO donors exhibited compatibility with currently prescribed antifungals against several different fungi species.

Advanced genetic techniques in fungal pathogen research

Although fungi have been important model organisms for solving genetic, molecular, and ecological problems, recently, they are also becoming an important source of infectious disease. Despite their high medical burden, fungal pathogens are understudied, and relative to other pathogenic microbes, less is known about how their gene functions contribute to disease. This is due, in part, to a lack of powerful genetic tools to study these organisms. In turn, this has resulted in inappropriate treatments and diagnostics and poor disease management. There are a variety of reasons genetic studies were challenging in pathogenic fungi, but in recent years, most of them have been overcome or advances have been made to circumvent these barriers. In this minireview, we highlight how recent advances in genetic studies in fungal pathogens have resulted in the discovery of important biology and potential new antifungals and have created the tools to comprehensively study these important pathogens.

Allosteric inhibition of tRNA synthetase Gln4 by N-pyrimidinyl-β-thiophenylacrylamides exerts highly selective antifungal activity

Candida species are among the most prevalent causes of systemic fungal infections, which account for ∼1.5 million annual fatalities. Here, we build on a compound screen that identified the molecule N-pyrimidinyl-β-thiophenylacrylamide (NP-BTA), which strongly inhibits Candida albicans growth. NP-BTA was hypothesized to target C. albicans glutaminyl-tRNA synthetase, Gln4. Here, we confirmed through in vitro amino-acylation assays NP-BTA is a potent inhibitor of Gln4, and we defined how NP-BTA arrests Gln4's transferase activity using co-crystallography. This analysis also uncovered Met496 as a critical residue for the compound's species-selective target engagement and potency. Structure-activity relationship (SAR) studies demonstrated the NP-BTA scaffold is subject to oxidative and non-oxidative metabolism, making it unsuitable for systemic administration. In a mouse dermatomycosis model, however, topical application of the compound provided significant therapeutic benefit. This work expands the repertoire of antifungal protein synthesis target mechanisms and provides a path to develop Gln4 inhibitors.

Antifungal drug discovery for targeting Candida albicans morphogenesis through structural dynamics study

In response to the escalating threat of drug-resistant fungi to human health, there is an urgent need for innovative strategies. Our focus is on addressing this challenge by exploring a previously untapped target, yeast casein kinase (Yck2), as a potential space for antifungal development. To identify promising antifungal candidates, we conducted a thorough screening of the diverse-lib drug-like molecule library, comprising 99,288 molecules. Five notable drug-like compounds with diverse-lib IDs 24334243, 24342416, 17516746, 17407455, and 24360740 were selected based on their binding energy scores surpassing 11 Kcal/mol. Our investigation delved into the interaction studies and dynamic stability of these compounds. Remarkably, all selected molecules demonstrated acceptable RMSD values during the 200 ns simulation, indicating their stable nature. Further analysis through Principal Component Analysis (PCA)-based Free Energy Landscape (FEL) revealed minimal energy transitions for most compounds, signifying dynamic stability. Notably, the two compounds exhibited slightly different behaviour in terms of energy transitions. These findings mark a significant breakthrough in the realm of antifungal drugs against C. albicans by targeting the Yck2 protein. However, it is crucial to note that additional experimental validation is imperative to assess the efficacy of these molecules as potential antifungal candidates. This study serves as a promising starting point for further exploration and development in the quest for effective antifungal solutions.Communicated by Ramaswamy H. Sarma.

Amphotericin B in the Era of New Antifungals: Where Will It Stand?

Amphotericin B (AmB) has long stood as a cornerstone in the treatment of invasive fungal infections (IFIs), especially among immunocompromised patients. However, the landscape of antifungal therapy is evolving. New antifungal agents, boasting novel mechanisms of action and better safety profiles, are entering the scene, presenting alternatives to AmB's traditional dominance. This shift, prompted by an increase in the incidence of IFIs, the growing demographic of immunocompromised individuals, and changing patterns of fungal resistance, underscores the continuous need for effective treatments. Despite these challenges, AmB's broad efficacy and low resistance rates maintain its essential status in antifungal therapy. Innovations in AmB formulations, such as lipid complexes and liposomal delivery systems, have significantly mitigated its notorious nephrotoxicity and infusion-related reactions, thereby enhancing its clinical utility. Moreover, AmB's efficacy in treating severe and rare fungal infections and its pivotal role as prophylaxis in high-risk settings highlight its value and ongoing relevance. This review examines AmB's standing amidst the ever-changing antifungal landscape, focusing on its enduring significance in current clinical practice and exploring its potential future therapeutic adaptations.

The epidemiology of invasive fungal infections in transplant recipients

Transplant patients, including solid-organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients, are exposed to various types of complications, particularly rejection. To prevent these outcomes, transplant recipients commonly receive long-term immunosuppressive regimens that in turn make them more susceptible to a wide array of infectious diseases, notably those caused by opportunistic pathogens. Among these, invasive fungal infections (IFIs) remain a major cause of mortality and morbidity in both SOT and HSCT recipients. Despite the continuing improvement in early diagnostics and treatments of IFIs, the management of these infections in transplant patients is still complicated. Here, we provide an overview concerning the most recent trends in the epidemiology of IFIs in SOT and HSCT recipients by describing the prominent yeast and mold species involved, the timing of post-transplant IFIs and the risk factors associated with their occurrence in these particularly weak populations. We also give special emphasis into basic research advances in the field that recently suggested a role of the global and long-term prophylactic regimen in orchestrating various biological disturbances in the organism and conditioning the emergence of the most adapted fungal strains to the particular physiological profiles of transplant patients.

Clinical Distribution and Drug Susceptibility Characterization of Invasive Candida Isolates in a Tertiary Hospital of Xinjiang Province

Objective

This study aims to investigate the clinical distribution characteristics and drug susceptibility profiles of invasive Candida isolates in a tertiary hospital in Urumqi.

Methods

The examination was conducted on samples obtained from patients who were clinically diagnosed with invasive candidiasis in this hospital. A total of 109 strains of Candida strains were identified through the use of internal transcribed spacer (ITS) sequencing and fungal cultivation methods.The clinical distribution of the strains was analyzed. Antifungal drug susceptibility tests were performed using the Sensititre YO10 fungal drug susceptibility plate based on the micro-broth dilution method.

Results

Candida albicans had the highest percentage (51.38%) among 109 Candida isolates, followed by C. glabrata (18.35%) and C. tropicalis (15.60%). The isolates were predominantly found in the respiratory department (41.28%), intensive care unit (ICU) (31.19%), and infection department (9.17%).The results of drug susceptibility tests indicated that amphotericin B, 5-fluorocytosine, and echinocandins exhibited good in vitro antifungal activity, with a susceptibility rate of over 96%. However, the azoles demonstrated low antifungal activity, especially posaconazole and voriconazole, which had high resistance rates of 64.71% for C. tropicalis and 70% for C. glabrata, respectively.

Conclusion

In our hospital, Candida albicans was identified as the primary causal agent of invasive candidiasis. In terms of in vitro antifungal activity, echinocandins, amphotericin B, and 5-fluorocytosine demonstrated efficacy against invasive Candida infections. However, it was important to note that C. glabrata and C. tropicalis exhibited low susceptibility to azoles.

Global diversity, coexistence and consequences of resistome in inland waters

Human activities have long impacted the health of Earth's rivers and lakes. These inland waters, crucial for our survival and productivity, have suffered from contamination which allows the formation and spread of antibiotic-resistant genes (ARGs) and consequently, ARG-carrying pathogens (APs). Yet, our global understanding of waterborne pathogen antibiotic resistance remains in its infancy. To shed light on this, our study examined 1240 metagenomic samples from both open and closed inland waters. We identified 22 types of ARGs, 19 types of mobile genetic elements (MGEs), and 14 types of virulence factors (VFs). Our findings showed that open waters have a higher average abundance and richness of ARGs, MGEs, and VFs, with more robust co-occurrence network compared to closed waters. Out of the samples studied, 321 APs were detected, representing a 43 % detection rate. Of these, the resistance gene 'bacA' was the most predominant. Notably, AP hotspots were identified in regions including East Asia, India, Western Europe, the eastern United States, and Brazil. Our research underscores how human activities profoundly influence the diversity and spread of resistome. It also emphasizes that both abiotic and biotic factors play pivotal roles in the emergence of ARG-carrying pathogens.

Protocol for determination of phosphatidylinositol 3-phosphate levels and localization in Candida glabrata by confocal microscopy

Phosphatidylinositol 3-phosphate (PI3P) levels govern membrane trafficking in Candida glabrata. Here, we present a confocal imaging-based protocol for PI3P localization analysis using the GFP-FYVE (found in Fab1, YOTB, Vac1, and EEA1) fusion protein. We describe steps for cloning the FYVE domain into the GFP-containing vector backbone, transforming FYVE-GFP into C. glabrata, and preparing slides with FYVE-GFP-expressing C. glabrata cells. We then detail procedures for acquiring and analyzing images and quantifying signal data. This protocol is adaptable to subcellular localization analysis of other low-abundant lipid and protein molecules. For complete details on the use and execution of this protocol, please refer to Askari et al. (2023).1.

cyp51A mutations, protein modeling, and efflux pump gene expression reveals multifactorial complexity towards understanding Aspergillus section Nigri azole resistance mechanism

Black Aspergillus species are the most common etiological agents of otomycosis, and pulmonary aspergillosis. However, limited data is available on their antifungal susceptibility profiles and associated resistance mechanisms. Here, we determined the azole susceptibility profiles of black Aspergillus species isolated from the Indian environment and explored the potential resistance mechanisms through cyp51A gene sequencing, protein homology modeling, and expression analysis of selected genes cyp51A, cyp51B, mdr1, and mfs based on their role in imparting resistance against antifungal drugs. In this study, we have isolated a total of 161 black aspergilli isolates from 174 agricultural soil samples. Isolates had variable resistance towards medical azoles; approximately 11.80%, 3.10%, and 1.24% of isolates were resistant to itraconazole (ITC), posaconazole (POS), and voriconazole (VRC), respectively. Further, cyp51A sequence analysis showed that non-synonymous mutations were present in 20 azole-resistant Aspergillus section Nigri and 10 susceptible isolates. However, Cyp51A homology modeling indicated insignificant protein structural variations because of these mutations. Most of the isolates showed the overexpression of mdr1, and mfs genes. Hence, the study concluded that azole-resistance in section Nigri cannot be attributed exclusively to the cyp51A gene mutation or its overexpression. However, overexpression of mdr1 and mfs genes may have a potential role in drug resistance.

Enhancing near-infrared II photodynamic therapy with nitric oxide for eradicating multidrug-resistant biofilms in deep tissues

Nitric oxide (NO) enhanced photodynamic therapy (PDT) is a promising approach to overcome drug tolerance and resistance to biofilm but is limited by its short excitation wavelengths and low yield of reactive oxygen species (ROS). Herein, we develop a compelling degradable polymer-based near-infrared II (NIR-II, 1000-1700 nm) photosensitizer (PNIR-II), which can maintain 50 % PDT efficacy even under a 2.6 cm tissue barrier. Remarkably, PNIR-II is synthesized by alternately connecting the electron donor thiophene to the electron acceptors diketopyrrolopyrrole (DPP) and boron dipyrromethene (BODIPY), where the intramolecular charge transfer properties can be tuned to increase the intersystem crossover rate and decrease the internal conversion rate, thereby stabilizing the NIR-II photodynamic rather than photothermal effect. For exerting a combination therapy to eradicate multidrug-resistant biofilms, PNIR-II is further assembled into nanoparticles (NPs) with a synthetic glutathione-triggered NO donor polymer. Under 1064 nm laser radiation, NPs precisely release ROS and NO that triggered by over-expressed GSH in the biofilm microenvironment, thereby forming more bactericidal reactive nitrogen species (RNS) in vitro and in vivo in the mice model that orderly destroy biofilm of multidrug-resistant Staphylococcus aureus cultures from clinical patients. It thus provides a new outlook for destroy the biofilm of deep tissues.

Mitigating amphotericin B cytotoxicity through gliadin-casein nanoparticles: Insights into synthesis, optimization, characterization, in vitro release and cytotoxicity evaluation

Amphotericin B (AmB) is a widely used antifungal agent; however, its clinical application is limited due to severe side effects and nephrotoxicity associated with parenteral administration. In recent years, there has been growing interest in the utilization of food-grade materials as innovative components for nanotechnology-based drug delivery systems. This study introduces gliadin/casein nanoparticles encapsulating AmB (AmB_GliCas NPs), synthesized via antisolvent precipitation. Formulation was refined using a 24 factorial design, assessing the influence of gliadin and casein concentrations, as well as organic and aqueous phase volumes, on particle size, polydispersity index (PDI), and zeta potential. The optimal composition with 2 % gliadin, 0.5 % casein, and a 1:5 organic-to-aqueous phase ratio, yielded nanoparticles with a 442 nm size, a 0.307 PDI, a -20 mV zeta potential, and 82 % entrapment efficiency. AmB was confirmed to be amorphous within the nanoparticles by X-ray diffraction. These NPs released AmB sustainably over 96 h, primarily in its monomeric form. Moreover, NPs maintained stability in simulated gastrointestinal fluids with minimal drug release and showed significantly lower hemolytic activity and cytotoxicity on Vero cells than free AmB, suggesting their promise for oral AmB delivery.

Research progress of metal-organic framework nanozymes in bacterial sensing, detection, and treatment

The high efficiency and specificity of enzymes make them play an important role in life activities, but the high cost, low stability and high sensitivity of natural enzymes severely restrict their application. In recent years, nanozymes have become convincing alternatives to natural enzymes, finding utility across diverse domains, including biosensing, antibacterial interventions, cancer treatment, and environmental preservation. Nanozymes are characterized by their remarkable attributes, encompassing high stability, cost-effectiveness and robust catalytic activity. Within the contemporary scientific landscape, metal-organic frameworks (MOFs) have garnered considerable attention, primarily due to their versatile applications, spanning catalysis. Notably, MOFs serve as scaffolds for the development of nanozymes, particularly in the context of bacterial detection and treatment. This paper presents a comprehensive review of recent literature pertaining to MOFs and their pivotal role in bacterial detection and treatment. We explored the limitations and prospects for the development of MOF-based nanozymes as a platform for bacterial detection and therapy, and anticipate their great potential and broader clinical applications in addressing medical challenges.

A self-assembling peptide inhibits the growth and function of fungi via a wrapping strategy

Fungal infections contribute substantially to human morbidity and mortality. A particular concern is the high rate of mortality associated with invasive fungal infections, which often exceeds 50.0% despite the availability of several antifungal drugs. Herein, we show a self-assembling antifungal peptide (AFP), which is able to bind to chitin on the fungal cell wall and in situ form AFP nanofibers, wrapping fungi. As a result, AFP limits the proliferation of fungi, slows down the morphological transformation of biphasic fungi, and inhibits the adhesion of fungi to host cells and the formation of biofilms. Compared to the broad-spectrum antifungal fluconazole, AFP achieved a comparable inhibitory effect (MIC50 = 3.5 μM) on fungal proliferation. In addition, AFP significantly inhibited the formation of fungal biofilms with the inhibition rate of 69.6% at 1 μM, better than fluconazole (17.2% at 1 μM). In a skin infection model of mice, it was demonstrated that AFP showed significantly superior efficacy to fluconazole. In the systemic candidiasis mouse model, AFP showed similar efficacy to first-line antifungal amphotericin B (AmpB) and anidulafungin (AFG). This study provides a promising wrapping strategy for anti-fungal infection.

Polysaccharide-Based Coating with Excellent Antibiofilm and Repeatable Antifouling-Bactericidal Properties for Treating Infected Hernia

In recent years, the utilization of medical devices has gradually increased and implantation procedures have become common treatments. However, patients are susceptible to the risk of implant infections. This study utilized chemical grafting to immobilize polyethylenimine (QPEI) and hyaluronic acid (HA) on the surface of the mesh to improve biocompatibility while being able to achieve antifouling antimicrobial effects. From the in vitro testing, PP-PDA-Q-HA exhibited a high antibacterial ratio of 93% against S. aureus, 93% against E. coli, and 85% against C. albicans. In addition, after five rounds of antimicrobial testing, the coating continued to exhibit excellent antimicrobial properties; PP-PDA-Q-HA also inhibits the formation of bacterial biofilms. In addition, PP-PDA-Q-HA has good hemocompatibility and cytocompatibility. In vivo studies in animal implantation infection models also demonstrated the excellent antimicrobial properties of PP-PDA-Q-HA. Our study provides a promising strategy for the development of antimicrobial surface medical materials with excellent biocompatibility.

Antifungal Stewardship in Invasive Fungal Infections, a Systematic Review

INTRODUCTION

Invasive fungal infections (IFI) are a group of life-threatening diseases associated with significant morbidity, mortality and high healthcare costs. Some modern management programs known as AFS (antifungal stewardship programs) have now been developed. The purpose of this systematic review is to evaluate the different declinations of antifungal stewardship programs (AFPs).

METHODS

Articles were systematically reviewed using the PRISMA checklist 2020. EMBASE and MEDLINE/PubMED were searched using the term "antifungal stewardship" (2012-2022 data) on 2 January 2023. Eligible studies were those that described an AFS and included an intervention, performance evaluation and outcome measures.

RESULTS

A total of 22/796 studies were included. Approximately two-thirds (16) were published between 2018 and 2022. 16 (72.7%) stated a minimal complete AFS team. 12 (54.5%) adopted a non-compulsory AFS approach, 6(27.3%) had an Educational AFS and 4(18.2%) a compulsory AFS. Cost analyses of 12 studies showed a decrease for 7 (31.8%) compared to an increase for 5 (22.7%). In terms of outcomes, 18 studies showed a lower (10;45.5%) or the same (8;36.4%) pre-post intervention mortality rate.

CONCLUSION

AFS programs seem to be related to lower costs and better outcomes and should thus be implemented in tandem with antimicrobial stewardship programs.

Low-dose fluconazole as a useful and safe prophylactic option in patients receiving allogeneic hematopoietic stem cell transplantation

BACKGROUND

Invasive fungal infections (IFIs) represent a potentially fatal complication in patients who undergo allogeneic hematopoietic stem cell transplantation (HSCT) if the initiation of therapy is delayed. Some guidelines recommend antifungal prophylaxis or preemptive therapy for these patients depending on the risk of IFIs following allogeneic HSCT. This retrospective study aimed to identify the group of patients who safely undergo allogeneic HSCT with low-dose fluconazole (FLCZ) prophylaxis (100 mg/day).

METHODS

We retrospectively reviewed 107 patients who underwent their first allogeneic HSCT at Nagoya City University Hospital from January 1, 2010, to December 31, 2019. We analyzed the efficacy of low-dose FLCZ prophylaxis and investigated the relationship between major risk factors and antifungal prophylaxis failure (APF) within 100 days post-transplant.

RESULTS

Of the 107 patients, 70 received low-dose FLCZ prophylaxis, showing a cumulative incidence of APF of 37.1% and a proven/probable IFI rate of 4.3%. There were no fungal infection-related deaths, including Aspergillus infections, in the FLCZ prophylaxis group. In a multivariable analysis, cord blood transplantation (CBT) (subdistribution hazard ratio (SHR), 3.55; 95% confidence interval (CI), 1.44-8.77; p = 0.006) and abnormal findings on lung CT before transplantation (SHR, 2.24; 95% CI, 1.02-4.92; p = 0.044) were independent risk factors for APF in the FLCZ prophylaxis group.

CONCLUSION

Low-dose FLCZ prophylaxis is a useful and safe option for patients receiving allogeneic HSCT, except in those undergoing CBT or having any fungal risk features including history of fungal infections, positive fungal markers, and abnormal findings on lung CT before transplantation.

Antifungal activity and potential mechanism of action of Huangqin decoction against Trichophyton rubrum

Introduction. Trichophyton rubrum is a major causative agent of superficial dermatomycoses such as onychomycosis and tinea pedis. Huangqin decoction (HQD), as a classical traditional Chinese medicine formula, was found to inhibit the growth of common clinical dermatophytes such as T. rubrum in our previous drug susceptibility experiments.Hypothesis/Gap Statement. The antifungal activity and potential mechanism of HQD against T. rubrum have not yet been investigated.Aim. The aim of this study was to investigate the antifungal activity and explore the potential mechanism of action of HQD against T. rubrum.Methodology. The present study was performed to evaluate the antifungal activity of HQD against T. rubrum by determination of minimal inhibitory concentrations (MICs), minimal fungicidal concentrations (MFCs), mycelial growth, biomass, spore germination and structural damage, and explore its preliminary anti-dermatophyte mechanisms by sorbitol and ergosterol assay, HPLC-based ergosterol test, enzyme-linked immunosorbent assay and mitochondrial enzyme activity test.Results. HQD was able to inhibit the growth of T. rubrum significantly, with an MIC of 3.125 mg ml-1 and an MFC of 12.5 mg ml-1. It also significantly inhibited the hyphal growth, conidia germination and biomass growth of T. rubrum in a dose-dependent manner, and induced structural damage in different degrees for T. rubrum cells. HQD showed no effect on cell wall integrity, but was able to damage the cell membrane of T. rubrum by interfering with ergosterol biosynthesis, involving the reduction of squalene epoxidase (SE) and sterol 14α-demethylase P450 (CYP51) activities, and also affect the malate dehydrogenase (MDH), succinate dehydrogenase (SDH) and ATPase activities of mitochondria.Conclusion. These results revealed that HQD had significant anti-dermatophyte activity, which was associated with destroying the cell membrane and affecting the enzyme activities of mitochondria.

Deciphering the antifungal mechanism and functional components of cinnamomum cassia essential oil against Candida albicans through integration of network-based metabolomics and pharmacology, the greedy algorithm, and molecular docking

ETHNOPHARMACOLOGICAL RELEVANCE

Fungal pathogens can cause deadly invasive infections and have become a major global public health challenge. There is an urgent need to find new treatment options beyond established antifungal agents, as well as new drug targets that can be used to develop novel antifungal agents. Cinnamomum cassia is a tropical aromatic plant that has a wide range of applications in traditional Chinese medicine, especially in the treatment of bacterial and fungal infections.

AIM OF THE STUDY

The present study aimed to explore the mechanism of action and functional components of Cinnamomum cassia essential oil (CEO) against Candida albicans using an integrated strategy combining network-based metabolomics and pharmacology, the greedy algorithm and molecular docking.

MATERIALS AND METHODS

CEO was extracted using hydrodistillation and its chemical composition was identified by GC-MS. Cluster analysis was performed on the compositions of 19 other CEOs from the published literature, as well as the sample obtained in this study. The damages of C. albicans cells upon treatment with CEO was observed using a scanning electron microscope. The mechanisms of its antifungal effect at a subinhibitory concentration of 0.1 × MIC were determined using microbial metabolomics and network analysis. The functional components were studied using the greedy algorithm and molecular docking.

RESULTS

A total of 69 compounds were identified in the chemical analysis of CEO, which accounted for 90% of the sample. The major compounds were terpenoids (34.04%), aromatic compounds (4.52%), aliphatic compounds (0.9%), and others. Hierarchical cluster analysis of the compositions of 20 essential oils extracted from Cinnamomum cassia grown in different geographical locations showed a wide diversity of chemical composition with four major chemotypes. CEO showed strong antifungal activity and caused destruction of cell membranes in a concentration-dependent way. Metabolic fingerprint analysis identified 29 metabolites associated with lipid metabolism, which were mapped to 23 core targets mainly involved in fatty acid biosynthesis and metabolism. Six antifungal functional components of CEO were identified through network construction, greedy algorithm and molecular docking, including trans-cinnamaldehyde, δ-cadinol, ethylcinnamate, safrole, trans-anethole, and trans-cinnamyl acetate, which showed excellent binding with specific targets of AKR1B1, PPARG, BCHE, CYP19A1, CYP2C19, QPCT, and CYP51A1.

CONCLUSIONS

This study provides a systematic understanding of the antifungal activity of CEO and offers an integrated strategy for deciphering the potential metabolism and material foundation of complex component drugs.

Photonic Si microwell architectures for rapid antifungal susceptibility determination of Candida auris

We present the application of a photonic silicon chip-based optical sensor system for expeditious and phenotypic antifungal susceptibility testing. This label-free diagnostic assay optically monitors the growth of Candida auris at varying antifungal concentrations on a microwell-structured silicon chip in real-time, and antifungal susceptibility is detected within 6 h, four times faster than in the current gold standard method.

Antifungal activity of eumelanin-inspired indoylenepheyleneethynylene against Cryptococcus neoformans

Cryptococcus neoformans is an opportunistic fungal pathogen that causes meningitis in >152,000 immunocompromised individuals annually, leading to 112,000 yearly deaths. The four classes of existing antifungal agents target plasma membrane sterols (ergosterol), nucleic acid synthesis, and cell wall synthesis. Existing drugs are not highly effective against Cryptococcus, and antifungal drug resistance is an increasing problem. A novel antimicrobial compound, a eumelanin-inspired indoylenepheyleneethynylene, EIPE-1, was synthesized and has antimicrobial activity against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MSRA), but not towards Gram-negative organisms. Based on EIPE-1's antibacterial activity, we hypothesized that EIPE-1 could have antifungal activity. For these studies, we tested EIPE-1 against C. neoformans strain H99 and 6 additional cryptococcal clinical isolates. We examined antifungal activity, cytotoxicity, effects on fungal gene expression, and mechanism of action of EIPE-1. Results showed that EIPE-1 has fungicidal effects on seven cryptococcal strains with MICs ranging from 1.56 to 3.125 μg/mL depending on the strain, and it is non-toxic to mammalian cells. We conducted scanning and transmission electron microscopy on the exposed cells to examine structural changes to the organism following EIPE-1 treatment. Cells exposed displayed structural changes to their cell wall and membranes, with internal contents leaking out of the cells. To understand the effect of EIPE-1 on fungal gene expression, RNA sequencing was conducted. Results showed that EIPE-1 affects several processes involved stress response, ergosterol biosynthesis, capsule biosynthesis, and cell wall attachment and remodeling. Therefore, our studies demonstrate that EIPE-1 has antifungal activity against C. neoformans, which affects both cellular structure and gene expression of multiple fungal pathways involved in cell membrane stability and viability.

Pluronic F-127 Enhances the Antifungal Activity of Fluconazole against Resistant Candida Strains

Candida strains as the most frequent causes of infections, along with their increased drug resistance, pose significant clinical and financial challenges to the healthcare system. Some polymeric excipients were reported to interfere with the multidrug resistance mechanism. Bearing in mind that there are a limited number of marketed products with fluconazole (FLU) for the topical route of administration, Pluronic F-127 (PLX)/FLU formulations were investigated in this work. The aims of this study were to investigate (i) whether PLX-based formulations can increase the susceptibility of resistant Candida strains to FLU, (ii) whether there is a correlation between block polymer concentration and the antifungal efficacy of the FLU-loaded PLX formulations, and (iii) what the potential mode of action of PLX assisting FLU is. The yeast growth inhibition upon incubation with PLX formulations loaded with FLU was statistically significant. The highest efficacy of the azole agent was observed in the presence of 5.0 and 10.0% w/v of PLX. The upregulation of the CDR1/CDR2 genes was detected in the investigated Candida strains, indicating that the efflux of the drug from the fungal cell was the main mechanism of the resistance.

An Analysis of the Use of Systemic Antifungals (Fluconazole, Itraconazole, and Terbinafine) in Galicia, Spain, between 2019 and 2022

In the present work, we examined the consumption of systemic antifungals (fluconazole, itraconazole, and terbinafine) in outpatients in the four provinces of Galicia, Spain, between 2019 and 2022. We also described the variability in the use of these types of drugs between these provinces. In addition, we detected any deviation in consumption at a seasonal level and analyzed possible changes during the study period. A descriptive, cross-sectional, and retrospective study of the use of antifungals, expressed in terms of a defined daily dose per 1000 inhabitants per day, was carried out. The results obtained revealed statistically significant differences between provinces and by the active principle consumed in the four Galician provinces (p < 0.001), which can be explained by multiple factors. This study also revealed that there was stable consumption during the study period, with no significant seasonal differences observed. This study represents a contribution to the knowledge about the consumption of antifungals for systemic use in Galicia and serves as a basis for subsequent studies. This will allow us to understand the consumption patterns of these types of drugs and, ultimately, will help to establish stewardship strategies and prevent the development of resistance.

Antifungal susceptibility testing following the CLSI M27 document, along with the measurement of MFC/MIC ratio, could be the optimal approach to detect amphotericin B resistance in Clavispora (Candida) lusitaniae. Susceptibility patterns of contemporary isolates of this species

Antifungal susceptibility testing (AST) is crucial in clinical settings to guide appropriate therapy. Nevertheless, discrepancies between treatment response and some results still persist, particularly in detecting resistance to amphotericin B (AMB) in Clavispora (Candida) lusitaniae. This study aimed to assess the susceptibility patterns of 48 recent isolates of C. lusitaniae to 9 antifungal agents and explore the feasibility of using a CLSI reference-based method to identify AMB resistance. Microdilution techniques revealed a wide range of minimal inhibitory concentration (MIC) values for azole antifungals, while echinocandins and AMB exhibited a narrow range of MIC values, with all strains considered wild-type for the tested polyene and echinocandins. However, when agar diffusion (ellipsometry) was employed for AST, certain strains displayed colonies within the inhibition ellipse, indicating potential resistance. Interestingly, these strains did not respond to AMB treatment and were isolated during AMB treatment (breakthrough). Moreover, the evaluation of AMB minimum fungicidal concentrations (MFCs) indicated that only the strains with colonies inside the ellipse had MFC/MIC ratios ≥ 4, suggesting reduced fungicidal activity. In conclusion, this study confirms the effectiveness of ellipsometry with RPMI-1640 2% glucose agar for detecting AMB resistance in C. lusitaniae. Additionally, the proposed approach of culturing "clear" wells in the microdilution method can aid in uncovering resistant strains. The findings highlight the importance of appropriate AST methods to guide effective treatment strategies for deep-seated candidiasis caused by C. lusitaniae. Further collaborative studies are warranted to validate these findings and improve the detection of AMB clinical resistance.