scholarly journals Amphotericin B and Other Polyenes—Discovery, Clinical Use, Mode of Action and Drug Resistance

2020 ◽  
Vol 6 (4) ◽  
pp. 321
Author(s):  
Hans Carolus ◽  
Siebe Pierson ◽  
Katrien Lagrou ◽  
Patrick Van Dijck
Keyword(s):  
Drug Resistance ◽  
Amphotericin B ◽  
Mode Of Action ◽  
Fungal Infections ◽  
Resistance Mechanisms ◽  
Antifungal Drugs ◽  
Clinical Use ◽  
Candida Auris ◽  
Resistance Development ◽  
Resistant Species

Although polyenes were the first broad spectrum antifungal drugs on the market, after 70 years they are still the gold standard to treat a variety of fungal infections. Polyenes such as amphotericin B have a controversial image. They are the antifungal drug class with the broadest spectrum, resistance development is still relatively rare and fungicidal properties are extensive. Yet, they come with a significant host toxicity that limits their use. Relatively recently, the mode of action of polyenes has been revised, new mechanisms of drug resistance were discovered and emergent polyene resistant species such as Candida auris entered the picture. This review provides a short description of the history and clinical use of polyenes, and focusses on the ongoing debate concerning their mode of action, the diversity of resistance mechanisms discovered to date and the most recent trends in polyene resistance development.

scholarly journals Combination Therapy to Treat Fungal Biofilm-Based Infections

2020 ◽  
Vol 21 (22) ◽  
pp. 8873
Author(s):  
Jana Tits ◽  
Bruno P. A. Cammue ◽  
Karin Thevissen
Keyword(s):  
Combination Therapy ◽  
Amphotericin B ◽  
Mode Of Action ◽  
Fungal Infections ◽  
Antifungal Drugs ◽  
In Vitro Methods ◽  
Combination Treatments ◽  
Liposomal Formulations ◽  
Similar Mode

An increasing number of people is affected by fungal biofilm-based infections, which are resistant to the majority of currently-used antifungal drugs. Such infections are often caused by species from the genera Candida, Aspergillus or Cryptococcus. Only a few antifungal drugs, including echinocandins and liposomal formulations of amphotericin B, are available to treat such biofilm-based fungal infections. This review discusses combination therapy as a novel antibiofilm strategy. More specifically, in vitro methods to discover new antibiofilm combinations will be discussed. Furthermore, an overview of the main modes of action of promising antibiofilm combination treatments will be provided as this knowledge may facilitate the optimization of existing antibiofilm combinations or the development of new ones with a similar mode of action.

scholarly journals Genomewide Elucidation of Drug Resistance Mechanisms for Systemically Used Antifungal Drugs Amphotericin B, Caspofungin, and Voriconazole in the Budding Yeast

2019 ◽  
Vol 63 (9) ◽  
Author(s):  
Cigdem Balkan ◽  
Ilkcan Ercan ◽  
Esin Isik ◽  
Esra Sahin Akdeniz ◽  
Orhan Balcioglu ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Amphotericin B ◽  
Fungal Infections ◽  
Budding Yeast ◽  
Expression Patterns ◽  
Drug Susceptibility ◽  
Antifungal Drugs ◽  
Yeast Cells ◽  
Content Type ◽  
New Genes

ABSTRACT There are only a few antifungal drugs used systemically in treatment, and invasive fungal infections that are resistant to these drugs are an emerging problem in health care. In this study, we performed a high-copy-number genomic DNA (gDNA) library screening to find and characterize genes that reduce susceptibility to amphotericin B, caspofungin, and voriconazole in Saccharomyces cerevisiae. We identified the PDR16 and PMP3 genes for amphotericin B, the RMD9 and SWH1 genes for caspofungin, and the MRS3 and TRI1 genes for voriconazole. The deletion mutants for PDR16 and PMP3 were drug susceptible, but the other mutants had no apparent susceptibility. Quantitative-PCR analyses suggested that the corresponding drugs upregulated expression of the PDR16, PMP3, SWH1, and MRS3 genes. To further characterize these genes, we also profiled the global expression patterns of the cells after treatment with the antifungals and determined the genes and paths that were up- or downregulated. We also cloned Candida albicans homologs of the PDR16, PMP3, MRS3, and TRI1 genes and expressed them in S. cerevisiae. Heterologous expression of Candida homologs also provided reduced drug susceptibility to the budding yeast cells. Our analyses suggest the involvement of new genes in antifungal drug resistance.

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

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.

scholarly journals Carrier-Mediated Drug Uptake in Fungal Pathogens

Genes ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1324
Author(s):  
Mónica Galocha ◽  
Inês Vieira Costa ◽  
Miguel Cacho Teixeira
Keyword(s):  
Drug Resistance ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Current Knowledge ◽  
Pathogenic Fungi ◽  
Resistance Mechanisms ◽  
Antifungal Drugs ◽  
Major Facilitator Superfamily ◽  
Drug Uptake ◽  
Human Pathogens

Candida, Aspergillus, and Cryptococcus species are the most frequent cause of severe human fungal infections. Clinically relevant antifungal drugs are scarce, and their effectiveness are hampered by the ability of fungal cells to develop drug resistance mechanisms. Drug effectiveness and drug resistance in human pathogens is very often affected by their “transportome”. Many studies have covered a panoply of drug resistance mechanisms that depend on drug efflux pumps belonging to the ATP-Binding Cassette and Major Facilitator Superfamily. However, the study of drug uptake mechanisms has been, to some extent, overlooked in pathogenic fungi. This review focuses on discussing current knowledge on drug uptake systems in fungal pathogens, highlighting the need for further studies on this topic of great importance. The following subjects are covered: (i) drugs imported by known transporter(s) in pathogenic fungi; and (ii) drugs imported by known transporter(s) in the model yeast Saccharomyces cerevisiae or in human parasites, aimed at the identification of their homologs in pathogenic fungi. Besides its contribution to increase the understanding of drug-pathogen interactions, the practical implications of identifying drug importers in human pathogens are discussed, particularly focusing on drug development strategies.

Antifúngicos poliénicos. Mecanismo de acción y aplicaciones

2020 ◽  
Vol 63 (2) ◽  
pp. 7-17
Author(s):  
Evelyn Rivera-Toledo ◽  
Alan Uriel Jiménez-Delgadillo ◽  
Patricia Manzano-Gayosso
Keyword(s):  
Antifungal Activity ◽  
Key Words ◽  
Secondary Metabolism ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Variable Number ◽  
Therapeutic Failure ◽  
Morbidity And Mortality ◽  
Clinical Use

The first compounds with specific antifungal activity were identified in the middle of the last century as a product of the secondary metabolism of bacteria of the order Actinomycetales, and their clinical use significantly diminished the morbidity and mortality associated with severe fungal infections. Many of such biosynthetic compounds are characterized by a chemical polygenic structure, with a variable number of carbon-carbon double bonds. Currently, besides polygenic antimycotics, there are other antifungal agents, such as the azole compounds, that have less toxicity in patients; however, cases of therapeutic failure with such compounds have been documented, therefore, the use of polygenics is still the best alternative in such cases. This review presents data about the properties and applications of antifungal-polygenic compounds using amphotericin B as a model. Key words: Amphotericin B; antifungal polyenes; ergosterol

scholarly journals The importance of rapid diagnosis for multidrug-resistant Candida: an interview with Maurizio Sanguinetti

2019 ◽  
Vol 14 (12) ◽  
pp. 1011-1012
Author(s):  
Maurizio Sanguinetti
Keyword(s):  
Infectious Diseases ◽  
Fungal Pathogens ◽  
Fungal Infections ◽  
Resistance Mechanisms ◽  
Rapid Diagnosis ◽  
Antifungal Drugs ◽  
Full Professor ◽  
Research Activity ◽  
Diagnostic Strategies ◽  
Personalized Care

In this exclusive interview, Maurizio Sanguinetti discusses current issues with Candida fungal infection diagnoses, in light of its rising resistance to antifungal drugs. This interview was conducted by Ellen Colvin, Editor of Future Microbiology. Maurizio Sanguinetti, MD, is full Professor of Microbiology at the Università Cattolica del Sacro Cuore of Rome, Italy, and Director of the Institute of Microbiology and Chief of the Department of Laboratory Sciences and Infectious Diseases Sciences at the Fondazione Policlinico Agostino Gemelli IRCCS of Rome, Italy. For several years, the research activity of Maurizio Sanguinetti has mainly focused on the development of molecular methods for the rapid diagnosis of bacterial, mycobacterial and fungal infections; the elucidation of virulence and antimicrobial resistance mechanisms in clinically relevant bacterial and fungal pathogens; the characterization of the human microbiota in relationship to infectious and noninfectious diseases and implementation of new diagnostic strategies for the personalized care of patients with infectious diseases.

scholarly journals Candida duobushaemulonii: An Old But Unreported Pathogen

2020 ◽  
Vol 6 (4) ◽  
pp. 374
Author(s):  
Irene Jurado-Martín ◽  
Cristina Marcos-Arias ◽  
Esther Tamayo ◽  
Andrea Guridi ◽  
Piet W. J. de Groot ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Related Species ◽  
Antifungal Drugs ◽  
Candida Auris ◽  
Closely Related Species ◽  
Identification Methods ◽  
Phenotypic Identification ◽  
Candida Intermedia ◽  
Candida Haemulonii

Candidiasis caused by species of the Candida haemulonii complex (Candida haemulonii and Candida duobushaemulonii) and closely related species, Candida auris and Candida pseudohaemulonii are increasing. These species often show reduced susceptibility to antifungal drugs, such as azoles and amphotericin B or, less frequently, echinocandins. However, conventional phenotypic identification methods are unable to accurately differentiate these species and, therefore, their prevalence may have been underestimated. In this study, 150 isolates that were probably misidentified were reanalyzed using two novel PCR approaches. We found that one isolate previously identified in 1996 as Candida intermedia was C. duobushaemulonii, being one of the oldest isolates of this species described to date. We also found that this isolate had reduced susceptibility to fluconazole, itraconazole, and amphotericin B.

scholarly journals Assessment of Candida auris Response to Antifungal Drugs Using Time–Kill Assays and an Animal Model

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S73-S73 ◽  
Author(s):  
Ronen Ben-Ami ◽  
Liat Ashkenazi ◽  
Judith Berman ◽  
Nuphar Korolker ◽  
Anna Novikov
Keyword(s):  
Amphotericin B ◽  
Fungicidal Activity ◽  
Antifungal Drugs ◽  
Rank Test ◽  
Infection Model ◽  
Candida Auris ◽  
Fungistatic Activity ◽  
Kill Curve ◽  
Time Kill

Abstract Background Candida auris is an emerging nosocomial pathogen that is resistant to Fluconazole and variably susceptible to other systemic drug classes. Treatment with echinocandins has been recommended based on MICs in the susceptible range, but supporting in vivo data is lacking. Methods We tested the MIC of C. auris strains (n = 12) to fluconazole, voriconazole, posaconazole. anidulafungin, amphotericin B and flucytosine. Representative C. auris strains from Israel and South Africa, and a reference C. albicans strain were analysed using time–kill curve assays. Fungicidal activity was defined as reduction of ≥3 log from baseline CFU/ml. Response to caspofungin treatment was assessed in BALB/c mice immunosuppressed with cyclophosphamide and inoculated with 7 × 107C. auris cells by tail vein injection. Mice were treated from day +1 to day +7 with caspofungin (IP) at doses of 1 or 5 mg/kg and compared with sham-treated controls. Survival was assessed daily. Kaplan-Meier survival analyses were performed and treatment arms were compared using the log-rank test. Results Drug susceptibility results (MIC50 and MIC90) were: fluconazole, 64 and 128 mg/l; voriconazole, 0.5 and 24 mg/l; posaconazole, 0.5 and 27 mg/l; anidulafungin, 0.03 and 0.06 mg/l; amphotericin B, 2 and 8 mg/l; flucytosine, 0.3 and 1 mg/l. Time–kill curve analyses showed log reduction from baseline CFU concentration of −3.0 to −2.8 for fluconazole (MIC ×1), 5.6–6.1 for amphotericin B (MIC ×4) and −0.4 to −0.9 for caspofungin (MIC ×16), consistent with fungicidal activity of amphotericin B and weak fungistatic activity of caspofungin. In the mouse model, survival rate was similar with sham treatment (33%) and treatment with caspofungin 1 mg/kg/day (44%) and 5 mg/kg/day (22%), P = 0.7. Conclusion Despite generally low MIC, caspofungin has only mild fungistatic activity on C. auris and no effect on survival in a mouse infection model. Amphotericin B has fungicidal activity against C. auris. Disclosures All authors: No reported disclosures.

Antibiofilm activity of antifungal drugs, including the novel drug olorofim, against Lomentospora prolificans

2020 ◽  
Author(s):  
Lisa Kirchhoff ◽  
Silke Dittmer ◽  
Ann-Kathrin Weisner ◽  
Jan Buer ◽  
Peter-Michael Rath ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Antifungal Agents ◽  
Fungal Infections ◽  
Pathogenic Fungus ◽  
Antifungal Drugs ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity

Abstract Objectives Patients with immunodeficiency or cystic fibrosis frequently suffer from respiratory fungal infections. In particular, biofilm-associated fungi cause refractory infection manifestations, linked to increased resistance to anti-infective agents. One emerging filamentous fungus is Lomentospora prolificans. Here, the biofilm-formation capabilities of L. prolificans isolates were investigated and the susceptibility of biofilms to various antifungal agents was analysed. Methods Biofilm formation of L. prolificans (n = 11) was estimated by crystal violet stain and antibiofilm activity was additionally determined via detection of metabolically active biofilm using an XTT assay. Amphotericin B, micafungin, voriconazole and olorofim were compared with regard to their antibiofilm effects when added prior to adhesion, after adhesion and on mature and preformed fungal biofilms. Imaging via confocal laser scanning microscopy was carried out to demonstrate the effect of drug treatment on the fungal biofilm. Results Antibiofilm activities of the tested antifungal agents were shown to be most effective on adherent cells whilst mature biofilm was the most resistant. The most promising antibiofilm effects were detected with voriconazole and olorofim. Olorofim showed an average minimum biofilm eradication concentration (MBEC) of 0.06 mg/L, when added prior to and after adhesion. The MBECs of voriconazole were ≤4 mg/L. On mature biofilm the MBECs of olorofim and voriconazole were higher than the previously determined MICs against planktonic cultures. In contrast, amphotericin B and especially micafungin did not exhibit sufficient antibiofilm activity against L. prolificans. Conclusions To our knowledge, this is the first study demonstrating the antibiofilm potential of olorofim against the human pathogenic fungus L. prolificans.

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