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Gupta AK, Mann A, Polla Ravi S, Wang T. Navigating fungal infections and antifungal stewardship: drug resistance, susceptibility testing, therapeutic drug monitoring and future directions. Ital J Dermatol Venerol 2024; 159:105-117. [PMID: 38088126 DOI: 10.23736/s2784-8671.23.07694-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/24/2024]
Abstract
Antifungal stewardship refers to the rational use of antifungal agents. Historically, in some instances, the misuse or overuse of antifungal agents has predisposed patients to an elevated risk of systemic side-effects and treatment resistance, as well as increased healthcare costs. Superficial mycoses, such as onychomycosis, are sometimes treated without any diagnostic testing and is associated with a high likelihood of self-diagnosis and self-treatment, potentially leading to the emergence of resistance against commonly used antifungals like terbinafine. Practitioners need to ensure that a proper clinical diagnosis is backed up by appropriate testing. This may include the traditional light microscopy and culture; additionally, molecular techniques (such as polymerase chain reaction, terbinafine gene mutational analysis) and antifungal susceptibility testing are considerations as appropriate. The choice of antifungal agent should be guided by what is the standard of care in the location where the clinician practices as well as more broadly state and national prescription patterns. Recently, reports of treatment resistance concerning both superficial and deep fungal infections have added another layer of difficulty to clinical practice. This review aims to explore the phenomenon of antifungal drug resistance, and highlights the importance of adopting antifungal stewardship programs. We provide an overview of treatment resistance and mechanisms of resistance reported thus far in dermatophytes. Challenges of performing antifungal susceptibility testing and therapeutic drug monitoring are discussed, as well as principles, recommendations and future directions of antifungal stewardship programs.
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Affiliation(s)
- Aditya K Gupta
- Division of Dermatology, Department of Medicine, University of Toronto, Toronto, ON, Canada -
- Mediprobe Research Inc, London, ON, Canada -
| | | | | | - Tong Wang
- Mediprobe Research Inc, London, ON, Canada
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Lopes MER, Bitencourt TA, Sanches PR, Martins MP, Oliveira VM, Rossi A, Martinez-Rossi NM. Alternative Splicing in Trichophyton rubrum Occurs in Efflux Pump Transcripts in Response to Antifungal Drugs. J Fungi (Basel) 2022; 8:jof8080878. [PMID: 36012866 PMCID: PMC9410333 DOI: 10.3390/jof8080878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/15/2022] [Accepted: 08/15/2022] [Indexed: 12/02/2022] Open
Abstract
Dermatophytes are challenging to treat because they have developed many strategies to neutralize the stress triggered by antifungals. Drug tolerance is achieved by mechanisms such as drug efflux and biofilm formation, and cellular efflux is a consequence of the synergistic and compensatory regulation of efflux pumps. Alternative splicing (AS) has also been considered as a mechanism that enhances fungal adaptive responses. We used RNA-seq data from the dermatophyte Trichophyton rubrum exposed to undecanoic acid (UDA) to search for and validate AS in genes encoding efflux pumps. The magnitude of this phenomenon was evaluated using UDA and other antifungals (caspofungin, itraconazole, and terbinafine) in planktonic and biofilm cultures. In addition to the conventional isoforms, the efflux pump encoded by TERG_04309 presented two intron-retained isoforms. Biofilms trigger the simultaneous production of at least two isoforms. The intron-retained isoforms showed short lengths and topologically different organization. Furthermore, we identified the putative interaction of efflux pumps (TERG_04309 and TERG_04224). Co-expression of these genes suggests a synergistic action in antifungal resistance. Our data provide new insights into drug tolerance related to differential isoform usage and the co-expression of stress-responsive genes, which may lead to higher antifungal resistance, mainly in biofilms.
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Yamada T, Yaguchi T, Tamura T, Pich C, Salamin K, Feuermann M, Monod M. Itraconazole resistance of Trichophyton rubrum mediated by the ABC transporter TruMDR2. Mycoses 2021; 64:936-946. [PMID: 33896045 DOI: 10.1111/myc.13286] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/28/2021] [Accepted: 04/07/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND Dermatophytes showing reduced sensitivity to antifungal agents have emerged in several countries. One terbinafine resistant strain of Trichophyton rubrum, TIMM20092, also showed reduced sensitivity to itraconazole (ITC) and voriconazole (VRC). The expression of two genes (TruMDR2 and TruMDR3) encoding multidrug transporters of the ABC family was found to be highly up-regulated in this strain. Deletion of TruMDR3 in TIMM20092 abolished its resistance to VRC but only slightly reduced its resistance to ITC. OBJECTIVES We examined the potential of T rubrum to develop resistance to ITC by analysing the mechanism of ITC resistance in TIMM20092. METHODS The deletion of TruMDR2 by gene replacement was performed in TIMM20092 and one TruMDR3-lacking mutant (∆TruMDR3) previously generated from TIMM20092. TruMDR2 single and TruMDR2/TruMDR3 double mutants (∆TruMDR2 and ∆TruMDR2/3) were successfully obtained, respectively. RESULTS The suppression of TruMDR2 was shown to abolish resistance to ITC in TIMM20092 and the TruMDR3-lacking mutant, strongly suggesting that TruMDR2 is a major contributor to ITC resistance in TIMM20092. CONCLUSIONS Our study highlights the possible role of the ABC transporter TruMDR2 in ITC resistance of T. rubrum.
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Affiliation(s)
- Tsuyoshi Yamada
- Teikyo University Institute of Medical Mycology, Tokyo, Japan
- Asia International Institute of Infectious Disease Control, Teikyo University, Tokyo, Japan
| | - Takashi Yaguchi
- Medical Mycology Research Center, Chiba University, Chiba, Japan
| | - Takashi Tamura
- General Medical Education and Research Center, Teikyo University, Tokyo, Japan
| | - Christine Pich
- Department of Dermatology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Karine Salamin
- Department of Dermatology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Marc Feuermann
- Swiss-Prot group, SIB Swiss Institute of Bioinformatics, Geneva, Switzerland
| | - Michel Monod
- Department of Dermatology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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Gnat S, Łagowski D, Nowakiewicz A, Dyląg M, Osińska M. Complementary effect of mechanism of multidrug resistance in Trichophyton mentagrophytes isolated from human dermatophytoses of animal origin. Mycoses 2021; 64:537-549. [PMID: 33448025 DOI: 10.1111/myc.13242] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 12/30/2020] [Accepted: 01/10/2021] [Indexed: 02/05/2023]
Abstract
BACKGROUND Dermatophytoses have gained interest worldwide due to the increased resistance to terbinafine and azoles and difficulty in management of these refractory diseases. OBJECTIVES In this study, we identified and analysed Trichophyton mentagrophytes clinical isolates obtained from humans with infections of animal origin. METHODS We used quantitative real-time PCR (qRT-PCR) to examine the transcriptional modulation of three MDR genes (PDR1, MDR2 and MDR4) and analysed squalene epoxidase (SQLE) gene sequences from multidrug-resistant Trichophyton mentagrophytes isolates. RESULTS The expression profile revealed a 2- to 12-fold increase in mRNA accumulation in the presence of any of the antifungals, compared to cells incubated without drugs. A statistically significant relationship between the isolates exposed to itraconazole and increased expression of the tested genes was revealed. Substantially lower transcription levels were noted for cells exposed to luliconazole, that is, a third-generation azole. Additionally, in the case of 50% of terbinafine-resistant strains, Leu397Phe substitution in the SQLE gene was detected. Furthermore, the reduced susceptibility to itraconazole and voriconazole was overcome by milbemycin oxime. CONCLUSIONS In conclusion, our study shed more light on the role of the ABC transporter family in T. mentagrophytes, which, if overexpressed, can confer resistance to single azole drugs and even cross-resistance. Finally, milbemycin oxime could be an interesting compound supporting treatment with azole drugs in the case of refractory dermatomycoses.
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Affiliation(s)
- Sebastian Gnat
- Faculty of Veterinary Medicine, Department of Veterinary Microbiology, Institute of Preclinical Veterinary Sciences, University of Life Sciences, Lublin, Poland
| | - Dominik Łagowski
- Faculty of Veterinary Medicine, Department of Veterinary Microbiology, Institute of Preclinical Veterinary Sciences, University of Life Sciences, Lublin, Poland
| | - Aneta Nowakiewicz
- Faculty of Veterinary Medicine, Department of Veterinary Microbiology, Institute of Preclinical Veterinary Sciences, University of Life Sciences, Lublin, Poland
| | - Mariusz Dyląg
- Faculty of Biological Sciences, Department of Mycology and Genetics, Institute of Genetics and Microbiology, University of Wroclaw, Wroclaw, Poland
| | - Marcelina Osińska
- Faculty of Veterinary Medicine, Department of Veterinary Microbiology, Institute of Preclinical Veterinary Sciences, University of Life Sciences, Lublin, Poland
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Mercer DK, Stewart CS. Keratin hydrolysis by dermatophytes. Med Mycol 2019; 57:13-22. [PMID: 29361043 DOI: 10.1093/mmy/myx160] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/06/2017] [Indexed: 12/31/2022] Open
Abstract
Dermatophytes are the most common cause of superficial fungal infections (tinea infections) and are a specialized group of filamentous fungi capable of infecting and degrading keratinised tissues, including skin, hair, and nail. Essential to their pathogenicity and virulence is the production of a broad spectrum of proteolytic enzymes and other key proteins involved in keratin biodegradation and utilization of its breakdown products. The initial stage of biodegradation of native keratin is considered to be sulfitolysis, in which the extensive disulfide bridges present in keratin are hydrolyzed, although some secreted subtilisins can degrade dye-impregnated keratin azure without prior reduction (Sub3 and Sub4). Sulfitolysis facilitates the extracellular biodegradation of keratin by the dermatophytes' extensive array of endo- and exoproteases. The importance of dermatophyte proteases in infection is widely recognized, and these enzymes have also been identified as important virulence determinants and allergens. Finally, the short peptide and amino acid breakdown products are taken up by the dermatophytes, using as yet poorly characterised transporters, and utilized for metabolism. In this review, we describe the process of keratin biodegradation by dermatophytes, with an especial focus on recent developments in cutting edge molecular biology and '-omic' studies that are helping to dissect the complex process of keratin breakdown and utilization.
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Affiliation(s)
- Derry K Mercer
- NovaBiotics Ltd, Cruickshank Building, Craibstone, Aberdeen, AB21 9TR, United Kingdom
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Martinez-Rossi NM, Bitencourt TA, Peres NTA, Lang EAS, Gomes EV, Quaresemin NR, Martins MP, Lopes L, Rossi A. Dermatophyte Resistance to Antifungal Drugs: Mechanisms and Prospectus. Front Microbiol 2018; 9:1108. [PMID: 29896175 PMCID: PMC5986900 DOI: 10.3389/fmicb.2018.01108] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 05/09/2018] [Indexed: 12/24/2022] Open
Abstract
Dermatophytes comprise pathogenic fungi that have a high affinity for the keratinized structures present in nails, skin, and hair, causing superficial infections known as dermatophytosis. A reasonable number of antifungal drugs currently exist on the pharmaceutical market to control mycoses; however, their cellular targets are restricted, and fungi may exhibit tolerance or resistance to these agents. For example, the stress caused by antifungal and cytotoxic drugs in sub-inhibitory concentrations promotes compensatory stress responses, with the over-expression of genes involved in cellular detoxification, drug efflux, and signaling pathways being among the various mechanisms that may contribute to drug tolerance. In addition, the ATP-binding cassette transporters in dermatophytes that are responsible for cellular efflux can act synergistically, allowing one to compensate for the absence of the other, revealing the complexity of drug tolerance phenomena. Moreover, mutations in genes coding for target enzymes could lead to substitutions in amino acids involved in the binding of antifungal agents, hindering their performance and leading to treatment failure. The relevance of each one of these mechanisms of resistance to fungal survival is hard to define, mainly because they can act simultaneously in the cell. However, an understanding of the molecular mechanisms involved in the resistance/tolerance processes, the identification of new antifungal targets, as well as the prospective of new antifungal compounds among natural or synthetic products, are expected to bring advances and new insights that facilitate the improvement or development of novel strategies for antifungal therapy.
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Affiliation(s)
- Nilce M Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Tamires A Bitencourt
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Nalu T A Peres
- Department of Morphology, Federal University of Sergipe, Aracaju, Brazil
| | - Elza A S Lang
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Eriston V Gomes
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Natalia R Quaresemin
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Maíra P Martins
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Lucia Lopes
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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de Morais CB, Scopel M, Pedrazza GPR, da Silva FK, Dalla Lana DF, Tonello ML, Miotto STS, Machado MM, De Oliveira LFS, Fuentefria AM, Zuanazzi JAS. Anti-dermatophyte activity of Leguminosae plants from Southern Brazil with emphasis on Mimosa pigra (Leguminosae). J Mycol Med 2017; 27:530-538. [PMID: 28822705 DOI: 10.1016/j.mycmed.2017.07.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 07/10/2017] [Accepted: 07/17/2017] [Indexed: 11/28/2022]
Abstract
BACKGROUND Intensive prophylactic use of antifungals leads to the increase of drug resistance and the need for new and more effective treatments are real. Plants from Leguminosae family are rich in flavonoids, for which numerous biological activities have been described, including antifungal effects. PURPOSE To screen methanolic extracts from Leguminosae species looking for alternative sources for antifungal agents (anti-dermatophyte and anti-Candida) and their innocuity. METHODS Antifungal activity was evaluated using the strains Candida albicans, C. krusei, C. glabrata, C. tropicalis, C. parapsilosis, Epidermophyton floccosum, Trichophyton mentagrophytes, T. rubrum and, Microsporum gypseum in the broth microdilution method. Later, the minimum inhibitory concentration (MIC) for Mimosa pigra, Eriosema heterophyllum, and Chamaecrista nictitans was determined. The most promising extract was fractionated and cytotoxicity and genotoxicity of the most active fraction were also assayed. RESULTS Fungicide and/or fungistatic activity against dermatophyte strains were presented by 60% of the methanolic extracts assayed. M. pigra, E. heterophyllum, and C. nictitans methanolic extracts could inhibit dermatophyte strains at concentrations ranging from 1.9 to 1000μg/mL. M. pigra showed the lowest MIC values for a dichloromethane fraction (1.9μg/mL) without DNA damage at 10 and 50μg/mL and 100% of cell viability of human leukocytes. CONCLUSION Our results indicate that methanolic extracts from Leguminosae plants are potential sources of antifungal compounds, mainly the extract and fractions from M. pigra. The dichloromethane fraction from M. pigra did not showed in vitro toxicity according to the applied assays.
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Affiliation(s)
- C B de Morais
- Laboratório de Farmacognosia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Av. Ipiranga, 2752, CEP 90.610-000 Porto Alegre, RS, Brazil
| | - M Scopel
- Laboratório de Farmacognosia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Av. Ipiranga, 2752, CEP 90.610-000 Porto Alegre, RS, Brazil
| | - G P R Pedrazza
- Laboratório de Farmacognosia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Av. Ipiranga, 2752, CEP 90.610-000 Porto Alegre, RS, Brazil
| | - F K da Silva
- Laboratório de Micologia Aplicada, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - D F Dalla Lana
- Laboratório de Micologia Aplicada, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - M L Tonello
- Laboratório de Farmacognosia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Av. Ipiranga, 2752, CEP 90.610-000 Porto Alegre, RS, Brazil
| | - S T S Miotto
- Laboratório de Taxonomia de Angiospermas, Departamento de Botânica/Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - M M Machado
- Núcleo de Pesquisas em Bioquímica, Toxicologia e Imunologia, Curso de Farmácia, Universidade Federal do Pampa, Uruguaiana, Brazil
| | - L F S De Oliveira
- Núcleo de Pesquisas em Bioquímica, Toxicologia e Imunologia, Curso de Farmácia, Universidade Federal do Pampa, Uruguaiana, Brazil
| | - A M Fuentefria
- Laboratório de Micologia Aplicada, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - J A S Zuanazzi
- Laboratório de Farmacognosia, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Av. Ipiranga, 2752, CEP 90.610-000 Porto Alegre, RS, Brazil.
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Martins MP, Franceschini ACC, Jacob TR, Rossi A, Martinez-Rossi NM. Compensatory expression of multidrug-resistance genes encoding ABC transporters in dermatophytes. J Med Microbiol 2016; 65:605-610. [PMID: 27121717 DOI: 10.1099/jmm.0.000268] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genomic sequencing of several dermatophyte species has revealed that they show small differences in genetic content and genome organization, although each fungus has adapted to specific niches. Thus, it seemed relevant to compare gene expression between species. Here, we examined the transcription modulation of three ATP-binding cassette (ABC) transporter genes (pdr1, mdr2 and mdr4), which code for membrane transporter proteins in four species of Trichophyton ; T. interdigitale, T. rubrum, T. tonsurans and T. equinum . These fungal species were challenged with sub-lethal doses of griseofulvin, itraconazole, terbinafine and amphotericin B. A mutant strain of T. interdigitale, Δmdr2, was also analysed for the modulation of pdr1 and mdr4 genes to evaluate the possible functional interaction among these three genes. Disruption of the mdr2 gene resulted in the accumulation of high levels of mdr4 transcripts when challenged with griseofulvin, suggesting that the mdr4 gene is compensating for the inactivation of mdr2 by providing resistance to this antifungal. Although the three ABC transporter genes have high homology between the four dermatophytes analysed, it is likely that they have specific functions, suggesting that the action of each drug is dependent on other factors inherent to each species. Our data suggest that these ABC transporter genes act synergistically in dermatophytes, and they may compensate for one another when challenged with antifungal drugs. This may be an important cause of therapeutic failure when treating fungal infections.
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Affiliation(s)
- Maíra Pompeu Martins
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | | | - Tiago Rinaldi Jacob
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | - Antonio Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
| | - Nilce Maria Martinez-Rossi
- Department of Genetics, Ribeirão Preto Medical School, University of São Paulo, 14049-900 Ribeirão Preto, SP, Brazil
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