Gene Amplification of <i>CYP51B</i>: a New Mechanism of Resistance to Azole Compounds in Trichophyton indotineae

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

ABSTRACT

Trichophyton indotineae causes dermatophytosis that is resistant to terbinafine and azole compounds. The aim of this study was to determine the mechanisms of resistance to itraconazole (ITC) and voriconazole (VRC) in strains of T. indotineae. Two azole-sensitive strains (ITC MIC < 0.125 μg/mL; VRC MIC < 0.06 μg/mL) and four azole-resistant strains (ITC MIC ≥ 0.5 μg/mL; VRC MIC ≥ 0.5 μg/mL) were used for the investigation. The expression of MDR genes encoding multidrug transporters of the ABC family for which orthologs have been identified in Trichophyton rubrum and those of CYP51A and CYP51B encoding the targets of azole antifungal compounds were compared between susceptible and resistant strains. TinMDR3 and TinCYP51B were overexpressed in T. indotineae resistant strains. Only small differences in susceptibility were observed between TinMDR3 disruptants and parental strains overexpressing TinMDR3. Whole-genome sequencing of resistant strains revealed the creation of a variable number of TinCYP51B tandem repeats at the specific position of their genomes in three resistant strains. Downregulation of TinCYP51B by RNA interference (RNAi) restored the susceptibility of azole-resistant strains. In contrast, overexpression of TinCYP51B cDNA conferred resistance to a susceptible strain of T. indotineae. In conclusion, the reduced sensitivity of T. indotineae strains to azoles is mainly due to the overexpression of TinCYP51B resulting from additional copies of this gene.

Related collections

Most cited references 49

Record: found
Abstract: found
Article: not found

The cdr1B efflux transporter is associated with non-cyp51a-mediated itraconazole resistance in Aspergillus fumigatus.

Paul Bowyer, Gordon Ramage, David W. Denning … (2013)

Recent increases in triazole resistance in Aspergillus fumigatus have been attributed primarily to target site (cyp51A) mutations. A recent survey of resistant isolates in Manchester showed that >50% of resistant isolates had no mutation in cyp51A or its promoter. We investigated the mechanisms of resistance in clinical azole-resistant isolates without cyp51A mutations. Twelve azole-resistant isolates, 10 of which were itraconazole resistant, were studied. Bioinformatic comparisons between Candida albicans efflux genes and A. fumigatus genome data identified 20 putative azole transporter genes. Basal and azole-induced expression of these genes and cyp51A was quantified using RT-PCR with comparison with clinical azole-susceptible isolates. Function of high basal or itraconazole-induced expression transporters was tested by gene knockout in azole-susceptible and azole-resistant isolates. All susceptible strains showed minimal basal expression of cdr1B compared with 8 of 10 azole-resistant strains with high basal expression of this gene (>5-fold), 3 of which showed >30-fold increased expression. Knockout of this gene resulted in a 4-fold reduction in itraconazole, posaconazole and voriconazole MICs for a susceptible clinical isolate and a 4-fold reduction in itraconazole susceptibility in a clinical resistant isolate. One strain showed a >500-fold induction of cyp51A. No increase in basal expression or expression after induction was seen for the 18 remaining putative transporters. The reasons behind the shift away from target site mutation in azole-resistant isolates from Manchester are unknown. The modest change in expression of cdr1B in azole-susceptible strains implies that only study of resistant isolates will lead to further understanding of resistance mechanisms in A. fumigatus.

0 comments Cited 136 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

A new Aspergillus fumigatus resistance mechanism conferring in vitro cross-resistance to azole antifungals involves a combination of cyp51A alterations.

E. Mellado, G Garcia-Effron, L Alcázar-Fuoli … (2007)

Fourteen Aspergillus fumigatus clinical isolates that exhibited a pattern of reduced susceptibility to triazole drugs were analyzed. The sequences of the cyp51A gene from all isolates showed the presence of a point mutation at t364a, which led to the substitution of leucine 98 for histidine (L98H), together with the presence of two copies of a 34-bp sequence in tandem in the promoter of the cyp51A gene. Quantitative expression analysis (real-time PCR) showed up to an eightfold increase in the level of expression of the cyp51A gene compared to that by the susceptible strain. Three PCR fragments of one azole-resistant strain (strain CM2627) that included the promoter with the tandem repeat and part of cyp51A with the t364a mutation or PCR fragments with only one of the modifications were used to replace the cyp51A gene of an azole drug-susceptible A. fumigatus wild-type strain (strain CM237). Only transformants which had incorporated the tandem repeat in the promoter of the cyp51A gene and the L98H amino acid substitution exhibited similarly reduced patterns of susceptibility to all triazole agents and similarly increased levels of cyp51A expression, confirming that the combination of both alterations was responsible for the azole-resistant phenotype.

0 comments Cited 133 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Mechanisms of resistance to azole antifungal agents in Candida albicans isolates from AIDS patients involve specific multidrug transporters.

D Sanglard, K Kuchler, F Ischer … (1995)

Azole antifungal agents, and especially fluconazole, have been used widely to treat oropharyngeal candidiasis in patients with AIDS. An increasing number of cases of clinical resistance against fluconazole, often correlating with in vitro resistance, have been reported. To investigate the mechanisms of resistance toward azole antifungal agents at the molecular level in clinical C. albicans isolates, we focused on resistance mechanisms related to the cellular target of azoles, i.e., cytochrome P450(14DM) (14DM) and those regulating the transport or accumulation of fluconazole. The analysis of sequential isogenic C. albicans isolates with increasing levels of resistance to fluconazole from five AIDS patients showed that overexpression of the gene encoding 14DM either by gene amplification or by gene deregulation was not the major cause of resistance among these clinical isolates. We found, however, that fluconazole-resistant C. albicans isolates failed to accumulate 3H-labelled fluconazole. This phenomenon was reversed in resistant cells by inhibiting the cellular energy supply with azide, suggesting that resistance could be mediated by energy-requiring efflux pumps such as those described as ATP-binding cassette (ABC) multidrug transporters. In fact, some but not all fluconazole-resistant clinical C. albicans isolates exhibited up to a 10-fold relative increase in mRNA levels for a recently cloned ABC transporter gene called CDR1. In an azole-resistant C. albicans isolate not overexpressing CDR1, the gene for another efflux pump named BENr was massively overexpressed. This gene was cloned from C. albicans for conferring benomyl resistance in Saccharomyces cerevisiae. Therefore, at least the overexpression or the deregulation of these two genes potentially mediates resistance to azoles in C. albicans clinical isolates from AIDS patients with oropharyngeal candidiasis. Involvement of ABC transporters in azole resistance was further evidenced with S. cerevisiae mutants lacking specific multidrug transporters which were rendered hypersusceptible to azole derivatives including fluconazole, itraconazole, and ketoconazole.

0 comments Cited 129 times – based on 0 reviews      Review now

Bookmark

All references

Author and article information

Contributors

Tsuyoshi Yamada:

ORCID: https://orcid.org/0000-0002-1394-5455

Journal

Journal ID (nlm-ta): Antimicrob Agents Chemother

Journal ID (iso-abbrev): Antimicrob Agents Chemother

Journal ID (publisher-id): AAC

Title: Antimicrobial Agents and Chemotherapy

Publisher: American Society for Microbiology (1752 N St., N.W., Washington, DC )

ISSN (Print): 0066-4804

ISSN (Electronic): 1098-6596

Publication date (Electronic, pub): 12 May 2022

Publication date (Electronic, collection): June 2022

Publication date PMC-release: 12 May 2022

Volume: 66

Issue: 6

Electronic Location Identifier: e00059-22

Affiliations

[a ] Teikyo University Institute of Medical Mycology, Tokyo, Japan

[b ] Asia International Institute of Infectious Disease Control, Teikyo University, Tokyo, Japan

[c ] Medical Mycology Research Center, Chiba University, Chiba, Japan

[d ] Department of Dermatology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland

[e ] Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland

[f ] Swiss-Prot Group, SIB Swiss Institute of Bioinformatics, Geneva, Switzerland

Author notes

The authors declare no conflict of interest.

Author information

Tsuyoshi Yamada https://orcid.org/0000-0002-1394-5455

Emmanuella Guenova https://orcid.org/0000-0001-5478-8735

Marc Feuermann https://orcid.org/0000-0002-4187-2863

Michel Monod https://orcid.org/0000-0002-0695-4003

Article

Publisher ID: 00059-22 Publisher ID: aac.00059-22

DOI: 10.1128/aac.00059-22

PMC ID: 9211412

PubMed ID: 35546111

SO-VID: e9662c6f-40e9-44d3-939a-71036c7601bb

License:

This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.

History

Date received : 16 January 2022

Date revision requested : 9 February 2022

Date accepted : 3 April 2022

Page count

Figures: 7, Tables: 4, Equations: 0, References: 49, Pages: 18, Words: 10887

Funding

Funded by: The National BioResource Project-Pathogenic eukaryotic microorganisms in Japan;

Award Recipient : Takashi Yaguchi

Funded by: The Joint Usage/Research Program of the Medical Mycology Research Center, Chiba University;

Award ID: 21-11

Award Recipient : Tsuyoshi Yamada Award Recipient : Takashi Yaguchi

Funded by: Institute for Fermentation, Osaka (IFO), FundRef https://doi.org/10.13039/100007802;

Award ID: GK-2020-1-026

Award Recipient : Tsuyoshi Yamada

Custom metadata

cover-date June 2022

ScienceOpen disciplines: Infectious disease & Microbiology

Keywords: dermatophytes,trichophyton mentagrophytes type viii,trichophyton indotineae,itraconazole,voriconazole,resistance,abc transporters,cyp51b

Data availability:

ScienceOpen disciplines: Infectious disease & Microbiology

Keywords: dermatophytes, trichophyton mentagrophytes type viii, trichophyton indotineae, itraconazole, voriconazole, resistance, abc transporters, cyp51b

Gene Amplification of CYP51B: a New Mechanism of Resistance to Azole Compounds in Trichophyton indotineae

Read this article at

ABSTRACT

Related collections

European Journal of Microbiology and Immunology

Most cited references 49

The cdr1B efflux transporter is associated with non-cyp51a-mediated itraconazole resistance in Aspergillus fumigatus.

A new Aspergillus fumigatus resistance mechanism conferring in vitro cross-resistance to azole antifungals involves a combination of cyp51A alterations.

Mechanisms of resistance to azole antifungal agents in Candida albicans isolates from AIDS patients involve specific multidrug transporters.

Author and article information

Contributors

Journal

Affiliations

Author notes

Author information

Article

History

Page count

Funding

Categories

Custom metadata

Comments

Comment on this article

Similar content 279

Cited by 18

Most referenced authors 542