Differential Azole Antifungal Efficacies Contrasted Using a Saccharomyces cerevisiae Strain Humanized for Sterol 14α-Demethylase at the Homologous Locus

ABSTRACT Inhibition of sterol-14α-demethylase, a cytochrome P450 (CYP51, Erg11p), is the mode of action of azole antifungal drugs, and with high frequencies of fungal infections new agents are required. New drugs that target fungal CYP51 should not inhibit human CYP51, although selective inhibitors of the human target are also of interest as anticholesterol agents. A strain of Saccharomyces cerevisiae that was humanized with respect to the amino acids encoded at the CYP51 (ERG11) yeast locus (BY4741:huCYP51) was produced. The strain was validated with respect to gene expression, protein localization, growth characteristics, and sterol content. The MIC was determined and compared to that for the wild-type parental strain (BY4741), using clotrimazole, econazole, fluconazole, itraconazole, ketoconazole, miconazole, and voriconazole. The humanized strain showed up to >1,000-fold-reduced susceptibility to the orally active azole drugs, while the topical agents showed no difference. Data from growth kinetic measurements substantiated this finding but also revealed reduced effectiveness against the humanized strain for the topical drugs. Cellular sterol profiles reflected the decreased susceptibility of BY4741:huCYP51 and showed a smaller depletion of ergosterol and accumulation of 14α-methyl-ergosta-8, 24(28)-dien-3β-6α-diol than the parental strain under the same treatment conditions. This strain provides a useful tool for initial specificity testing for new drugs targeting CYP51 and clearly differentiates azole antifungals in a side-by-side comparison.

Download Full-text

Efficacy of Novel Schiff base Derivatives as Antifungal Compounds in Combination with Approved Drugs Against Candida Albicans

Medicinal Chemistry ◽

10.2174/1573406415666181203115957 ◽

2019 ◽

Vol 15 (6) ◽

pp. 648-658 ◽

Cited By ~ 1

Author(s):

Manzoor Ahmad Malik ◽

Shabir Ahmad Lone ◽

Parveez Gull ◽

Ovas Ahmad Dar ◽

Mohmmad Younus Wani ◽

...

Keyword(s):

Schiff Base ◽

Candida Albicans ◽

Antifungal Activity ◽

Fungal Infections ◽

Total Sterol ◽

Antifungal Drugs ◽

New Drugs ◽

Ergosterol Biosynthesis ◽

Dependent Manner ◽

Schiff Base Derivatives

Background: The increasing incidence of fungal infections, especially caused by Candida albicans, and their increasing drug resistance has drastically increased in recent years. Therefore, not only new drugs but also alternative treatment strategies are promptly required. Methods: We previously reported on the synergistic interaction of some azole and non-azole compounds with fluconazole for combination antifungal therapy. In this study, we synthesized some non-azole Schiff-base derivatives and evaluated their antifungal activity profile alone and in combination with the most commonly used antifungal drugs- fluconazole (FLC) and amphotericin B (AmB) against four drug susceptible, three FLC resistant and three AmB resistant clinically isolated Candida albicans strains. To further analyze the mechanism of antifungal action of these compounds, we quantified total sterol contents in FLC-susceptible and resistant C. albicans isolates. Results: A pyrimidine ring-containing derivative SB5 showed the most potent antifungal activity against all the tested strains. After combining these compounds with FLC and AmB, 76% combinations were either synergistic or additive while as the rest of the combinations were indifferent. Interestingly, none of the combinations was antagonistic, either with FLC or AmB. Results interpreted from fractional inhibitory concentration index (FICI) and isobolograms revealed 4-10-fold reduction in MIC values for synergistic combinations. These compounds also inhibit ergosterol biosynthesis in a concentration-dependent manner, supported by the results from docking studies. Conclusion: The results of the studies conducted advocate the potential of these compounds as new antifungal drugs. However, further studies are required to understand the other mechanisms and in vivo efficacy and toxicity of these compounds.

Download Full-text

Non-toxic Cobalt(III) Schiff Base Complexes with Broad Spectrum Antifungal Activity

10.26434/chemrxiv.12736505 ◽

2020 ◽

Author(s):

Angelo Frei ◽

A. Paden King ◽

Gabrielle J. Lowe ◽

Amy K. Cain ◽

Francesca L. Short ◽

...

Keyword(s):

Schiff Base ◽

Antifungal Activity ◽

Broad Spectrum ◽

Bacterial Infections ◽

Fungal Infections ◽

Antifungal Drugs ◽

New Drugs ◽

Schiff Base Complexes ◽

In Vivo Studies

Resistance to currently available antifungal drugs has quietly been on the rise but overshadowed by the alarming spread of antibacterial resistance. There is a striking lack of attention to the threat of drug resistant fungal infections, with only a handful of new drugs currently in development. Given that metal complexes have proven to be useful new chemotypes in the fight against diseases such as cancer, malaria, and bacterial infections, it stands to reason to explore their possible utility in treating fungal infections. Herein we report a series of cobalt(III) Schiff base complexes with broad spectrum antifungal activity. Some of these complexes (1-3) show minimum inhibitory concentrations (MIC) in the low micro- to nanomolar range against a series of Candida and Cryptococcus yeasts. Additionally, we demonstrate that these compounds show no cytotoxicity against both bacterial and human cells. Finally, we report first in vivo toxicity data on these compounds in Galleria mellonella, showing that doses as high as 266 mg/kg are tolerated without adverse effects, paving the way for further in vivo studies of these complexes. <br>

Download Full-text

Nitric Oxide-Releasing Nanoparticles Are Similar to Efinaconazole in Their Capacity to Eradicate Trichophyton rubrum Biofilms

Frontiers in Cellular and Infection Microbiology ◽

10.3389/fcimb.2021.684150 ◽

2021 ◽

Vol 11 ◽

Author(s):

Caroline Barcelos Costa-Orlandi ◽

Luis R. Martinez ◽

Níura Madalena Bila ◽

Joel M. Friedman ◽

Adam J. Friedman ◽

...

Keyword(s):

Nitric Oxide ◽

Trichophyton Rubrum ◽

Fungal Infections ◽

Antifungal Drugs ◽

New Drugs ◽

Prolonged Treatment ◽

Clinical Strain ◽

Causative Agents ◽

Nitric Oxide Releasing

Filamentous fungi such as Trichophyton rubrum and T. mentagrophytes, the main causative agents of onychomycosis, have been recognized as biofilm-forming microorganisms. Nitric oxide-releasing nanoparticles (NO-np) are currently in development for the management of superficial and deep bacterial and fungal infections, with documented activity against biofilms. In this context, this work aimed to evaluate, for the first time, the in vitro anti-T. rubrum biofilm potential of NO-np using standard ATCC MYA-4438 and clinical BR1A strains and compare it to commonly used antifungal drugs including fluconazole, terbinafine and efinaconazole. The biofilms formed by the standard strain produced more biomass than those from the clinical strain. NO-np, fluconazole, terbinafine, and efinaconazole inhibited the in vitro growth of planktonic T. rubrum cells. Similarly, NO-np reduced the metabolic activities of clinical strain BR1A preformed biofilms at the highest concentration tested (SMIC50 = 40 mg/mL). Scanning electron and confocal microscopy revealed that NO-np and efinaconazole severely damaged established biofilms for both strains, resulting in collapse of hyphal cell walls and reduced the density, extracellular matrix and thickness of the biofilms. These findings suggest that biofilms should be considered when developing and testing new drugs for the treatment of dermatophytosis. Development of a biofilm phenotype by these fungi may explain the resistance of dermatophytes to some antifungals and why prolonged treatment is usually required for onychomycosis.

Download Full-text

In Vitro Activity of Manogepix against Multidrug-Resistant and Panresistant Candida auris from the New York Outbreak

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01124-20 ◽

2020 ◽

Vol 64 (11) ◽

Cited By ~ 1

Author(s):

YanChun Zhu ◽

Shannon Kilburn ◽

Mili Kapoor ◽

Sudha Chaturvedi ◽

Karen Joy Shaw ◽

...

Keyword(s):

New York ◽

Fungal Infections ◽

Geometric Mean ◽

Multidrug Resistant ◽

Antifungal Drugs ◽

New Drugs ◽

Wild Type ◽

Candida Auris ◽

Content Type

ABSTRACT An ongoing Candida auris outbreak in the New York metropolitan area is the largest recorded to date in North America. Laboratory surveillance revealed NY C. auris isolates are resistant to fluconazole, with variable resistance to other currently used broad-spectrum antifungal drugs, and that several isolates are panresistant. Thus, there is an urgent need for new drugs with a novel mechanism of action to combat the resistance challenge. Manogepix (MGX) is a first-in-class agent that targets the fungal Gwt1 enzyme. The prodrug fosmanogepix is currently in phase 2 clinical development for the treatment of fungal infections. We evaluated the susceptibility of 200 New York C. auris isolates to MGX and 10 comparator drugs using CLSI methodology. MGX demonstrated lower MICs than comparators (MIC50 and MIC90, 0.03 mg/liter; range, 0.004 to 0.06 mg/liter). The local epidemiological cutoff value (ECV) for MGX indicated all C. auris isolates were within the population of wild-type (WT) strains; 0.06 mg/liter defines the upper limit of wild type (UL-WT). MGX was 8- to 32-fold more active than the echinocandins, 16- to 64-fold more active than the azoles, and 64-fold more active than amphotericin B. No differences were found in the MGX or comparators’ MIC50, MIC90, or geometric mean (GM) values when subsets of clinical, surveillance, and environmental isolates were evaluated. The range of MGX MIC values for six C. auris panresistant isolates was 0.008 to 0.015 mg/liter, and the median and mode MIC values were 0.015 mg/liter, demonstrating that MGX retains activity against these isolates. These data support further clinical evaluation of fosmanogepix for the treatment of C. auris infections, including highly resistant isolates.

Download Full-text

Evaluation of in vitro activity of manogepix against multidrug-resistant and pan-resistant Candida auris from the New York Outbreak

10.1101/2020.06.02.129916 ◽

2020 ◽

Author(s):

YanChun Zhu ◽

Shannon Kilburn ◽

Mili Kapoor ◽

Sudha Chaturvedi ◽

Karen Joy Shaw ◽

...

Keyword(s):

New York ◽

Fungal Infections ◽

Multidrug Resistant ◽

Antifungal Drugs ◽

New Drugs ◽

Candida Auris ◽

York Metropolitan Area ◽

Clinical Surveillance ◽

Laboratory Surveillance

ABSTRACTAn ongoing Candida auris outbreak in the New York metropolitan area is the largest recorded to date in North America. Laboratory surveillance revealed NY C. auris isolates are resistant to fluconazole, with variable resistance to other currently used broad-spectrum antifungal drugs, and that several isolates are pan-resistant. Thus, there is an urgent need for new drugs with a novel mechanism of action to combat the resistance challenge. Manogepix (MGX) is a first-in-class agent that targets the fungal Gwt1 enzyme. The prodrug, fosmanogepix, is currently in Phase 2 clinical development for the treatment of fungal infections. We evaluated the susceptibility of 200 New York C. auris isolates to MGX and 10 comparator drugs using CLSI methodology. MGX demonstrated lower MICs than comparators (MIC50 and MIC90 0.03 mg/L; range 0.004-0.06 mg/L). The MGX epidemiological cutoff value (ECV, 99% cutoff) for the tested C. auris isolates was 0.06 mg/L. MGX was 8-32-fold more active than the echinocandins, 16-64-fold more active than the azoles, and 64-fold more active than amphotericin B. No differences were found in the MGX or comparators’ MIC50, MIC90, or GEOMEAN values when subsets of clinical, surveillance, and environmental isolates were evaluated. The range of MGX MIC values for six C. auris pan-resistant isolates was 0.008-0.015 mg/L, and the median and mode MIC values were 0.015 mg/L, demonstrating that MGX retains activity against these isolates. These data support further clinical evaluation of fosmanogepix for the treatment of C. auris infections, including highly resistant isolates.

Download Full-text

Fungal Diseases in the 21st Century: The Near and Far Horizons

Pathogens and Immunity ◽

10.20411/pai.v3i2.249 ◽

2018 ◽

Vol 3 (2) ◽

pp. 183 ◽

Cited By ~ 17

Author(s):

Arturo Casadevall

Keyword(s):

21St Century ◽

Fungal Infections ◽

Medical Problem ◽

Modern Medicine ◽

Antifungal Drugs ◽

Fungal Diseases ◽

New Drugs ◽

Medical Mycology ◽

Research Investment ◽

Causative Agents

Fungal diseases became a major medical problem in the second half of the 20th century when advances in modern medicine together with the HIV epidemic resulted in large numbers of individuals with impaired immunity. Fungal diseases are difficult to manage because they tend to be chronic, hard to diagnose, and difficult to eradicate with antifungal drugs. This essay considers the future of medical mycology in the 21st century, extrapolating from current trends. In the near horizon, the prevalence of fungal diseases is likely to increase, as there will be more hosts with impaired immunity and drug resistance will inevitably increase after selection by antifungal drug use. We can expect progress in the development of new drugs, diagnostics, vaccines, and immunotherapies. In the far horizon, humanity may face new fungal diseases in association with climate change. Some current associations between chronic diseases and fungal infections could lead to the establishment of fungi as causative agents, which will greatly enhance their medical importance. All trends suggest that the importance of fungal diseases will increase in the 21st century, and enhanced human preparedness for this scourge will require more research investment in this group of infectious diseases.

Download Full-text

Non-toxic Cobalt(III) Schiff Base Complexes with Broad Spectrum Antifungal Activity

10.26434/chemrxiv.12736505.v1 ◽

2020 ◽

Author(s):

Angelo Frei ◽

A. Paden King ◽

Gabrielle J. Lowe ◽

Amy K. Cain ◽

Francesca L. Short ◽

...

Keyword(s):

Schiff Base ◽

Antifungal Activity ◽

Broad Spectrum ◽

Bacterial Infections ◽

Fungal Infections ◽

Antifungal Drugs ◽

New Drugs ◽

Schiff Base Complexes ◽

In Vivo Studies

Download Full-text

Drug Repurposing in Medical Mycology: Identification of Compounds as Potential Antifungals to Overcome the Emergence of Multidrug-Resistant Fungi

Pharmaceuticals ◽

10.3390/ph14050488 ◽

2021 ◽

Vol 14 (5) ◽

pp. 488

Author(s):

Lucie Peyclit ◽

Hanane Yousfi ◽

Jean-Marc Rolain ◽

Fadi Bittar

Keyword(s):

Opportunistic Infections ◽

Fungal Infections ◽

Drug Repurposing ◽

Multidrug Resistant ◽

Resistance Mechanisms ◽

Antifungal Drugs ◽

New Drugs ◽

Medical Community ◽

Medical Mycology ◽

Candida Auris

Immunodepression, whether due to HIV infection or organ transplantation, has increased human vulnerability to fungal infections. These conditions have created an optimal environment for the emergence of opportunistic infections, which is concomitant to the increase in antifungal resistance. The use of conventional antifungal drugs as azoles and polyenes can lead to clinical failure, particularly in immunocompromised individuals. Difficulties related to treating fungal infections combined with the time required to develop new drugs, require urgent consideration of other therapeutic alternatives. Drug repurposing is one of the most promising and rapid solutions that the scientific and medical community can turn to, with low costs and safety advantages. To treat life-threatening resistant fungal infections, drug repurposing has led to the consideration of well-known and potential molecules as a last-line therapy. The aim of this review is to provide a summary of current antifungal compounds and their main resistance mechanisms, following by an overview of the antifungal activity of non-traditional antimicrobial drugs. We provide their eventual mechanisms of action and the synergistic combinations that improve the activity of current antifungal treatments. Finally, we discuss drug repurposing for the main emerging multidrug resistant (MDR) fungus, including the Candida auris, Aspergillus or Cryptococcus species.

Download Full-text

The antifungal activities and biological consequences of BMVC-12C-P, a carbazole derivative against Candida species

Medical Mycology ◽

10.1093/mmy/myz071 ◽

2019 ◽

Vol 58 (4) ◽

pp. 521-529

Author(s):

Mandy Shen ◽

Pei-Tzu Li ◽

Yan-Jia Wu ◽

Ching-Hsuan Lin ◽

Eric Chai ◽

...

Keyword(s):

Candida Species ◽

Fungal Infections ◽

Antifungal Drugs ◽

New Drugs ◽

High Morbidity ◽

Carbazole Derivative ◽

Antifungal Activities ◽

Development Of Resistance ◽

Fluconazole Resistant ◽

Candida Infections

Abstract Fungal infections, particularly Candida species, have increased worldwide and caused high morbidity and mortality rates. The toxicity and development of resistance in present antifungal drugs justify the need of new drugs with different mechanism of action. BMVC-12C-P, a carbazole-type compound, has been found to dysfunction mitochondria. BMVC-12C-P displayed the strongest antifungal activities among all of the BMVC derivatives. The minimal inhibitory concentration (MIC) of BMVC-12C-P against Candida species ranged from 1 to 2 μg/ml. Fluconazole-resistant clinical isolates of Candida species were highly susceptible to BMVC-12C-P. The potent fungicidal activity of BMVC-12C-P relates to its impairing mitochondrial function. Furthermore, we found that the hyphae growth and biofilm formation were suppressed in C. albicans survived from BMVC-12C-P treatment. This study demonstrates the potential of BMVC-12C-P as an antifungal agent for treating Candida infections.

Download Full-text

Galleria mellonella for the Evaluation of Antifungal Efficacy against Medically Important Fungi, a Narrative Review

Microorganisms ◽

10.3390/microorganisms8030390 ◽

2020 ◽

Vol 8 (3) ◽

pp. 390 ◽

Cited By ~ 8

Author(s):

Sana Jemel ◽

Jacques Guillot ◽

Kalthoum Kallel ◽

Françoise Botterel ◽

Eric Dannaoui

Keyword(s):

Fungal Pathogens ◽

Galleria Mellonella ◽

Fungal Infections ◽

Antifungal Susceptibility ◽

Antifungal Drugs ◽

New Drugs ◽

Development Of Resistance ◽

Antifungal Efficacy

The treatment of invasive fungal infections remains challenging and the emergence of new fungal pathogens as well as the development of resistance to the main antifungal drugs highlight the need for novel therapeutic strategies. Although in vitro antifungal susceptibility testing has come of age, the proper evaluation of therapeutic efficacy of current or new antifungals is dependent on the use of animal models. Mammalian models, particularly using rodents, are the cornerstone for evaluation of antifungal efficacy, but are limited by increased costs and ethical considerations. To circumvent these limitations, alternative invertebrate models, such as Galleria mellonella, have been developed. Larvae of G. mellonella have been widely used for testing virulence of fungi and more recently have proven useful for evaluation of antifungal efficacy. This model is suitable for infection by different fungal pathogens including yeasts (Candida, Cryptococcus, Trichosporon) and filamentous fungi (Aspergillus, Mucorales). Antifungal efficacy may be easily estimated by fungal burden or mortality rate in infected and treated larvae. The aim of the present review is to summarize the actual data about the use of G. mellonella for testing the in vivo efficacy of licensed antifungal drugs, new drugs, and combination therapies.

Download Full-text