Cited by 815Antifungal resistance and susceptibilityDrug Transport and Resistance MechanismsFungal and yeast genetics research

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

Open access
Sanglard, D, Kuchler, K, Ischer, F, Pagani, J L, Monod, M, Bille, J·1995·Antimicrobial Agents and Chemotherapy

Abstract

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.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1128/aac.39.11.2378

Cites

48 of 48 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Overexpression of the efflux transporter genes CDR1, CDR2, and MDR1 is a common mechanism of drug resistance in C. albicans.

    “Overexpression of the efflux transporter genes CDR1 , CDR2 , and MDR1 is a common mechanism of drug resistance in this organism (10, 17, 26).”

    From Gain-of-Function Mutations in <i>UPC2</i> Are a Frequent Cause of <i>ERG11</i> Upregulation in Azole-Resistant Clinical Isolates of Candida albicans (2012) · cites this paper as [26]

    The Results and Discussion report increased CDR1 mRNA in some azole-resistant C. albicans isolates and implicate transporter overexpression in resistance. The paper examines CDR1 and BENr, not CDR2 or MDR1, and its findings in isolates from five AIDS patients do not establish that overexpression of all three named genes is a common resistance mechanism. (LLM, conf=0.88)

    Experimental — accuracy not yet measured
  • In C. albicans, upregulation of ABC transporters Cdr1 and Cdr2 and major facilitator transporter Mdr1 have been implicated in azole resistance.

    “For C. albicans, upregulation of the ATP-binding cassette (ABC) transporters, Cdr1 and Cdr2 (Candida drug resistance 1 and 2), and major facilitator transporter Mdr1 (multidrug resistance 1) have been implicated in azole resistance50,51.”

    From Molecular mechanisms governing antifungal drug resistance (2023) · cites this paper as [50]

  • In two separate studies, isolates of C. albicans taken from HIV-infected individuals had increased mRNA levels of CDR1, which has been shown to confer resistance to the azole antifungals.

    “In two separate studies, it was found that isolates of C. albicans taken from HIV-infected individuals had increased mRNA levels of CDR1, which has been shown to confer resistance to the azole antifungals.77–79”
  • ABC transporters Cdr1 and Cdr2 have both been well documented as drivers of azole resistance and were first implicated in clinical azole resistance in isolates in HIV-infected patients with oropharyngeal candidiasis.

    “The ATP-binding cassette (ABC) transporters Cdr1 and Cdr2 have both been well documented as drivers of azole resistance and were first implicated in clinical azole resistance in isolates in HIV-infected patients with oropharyngeal candidiasis.75–77”
  • Overexpression of the ABC transporters Cdr1 and Cdr2 results in efflux of all azole antifungals in Candida albicans.

    “Overexpression of the ATP binding cassette (ABC) transporters Cdr1 and Cdr2 results in the efflux of all azole antifungals”

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. [14]14. Hanahan, D. 1985. Techniques for transformation of E. coli , p. 109-135. In D. M. Glover (ed.), DNA cloning. A practical approach. IRL Press, Oxford.

Cited by

Sorted by citations

Authors
Sanglard, D., Kuchler, K., Ischer, F., Pagani, J. L., Monod, M., & Bille, J.
Affiliations
  • Centre Hospitalier Universitaire Vaudois (CH)
  • Institut de Microbiologie, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland.
Venue
Antimicrobial Agents and Chemotherapy
Published
1995-11
Volume
39
Issue
11
Pages
2378-2386
ISSN
  • 0066-4804 (ISSN-L)
  • 1098-6596
OpenAlex
W2115130703
Cited by
815
References
48
Citations by year
2026: 10 · 2025: 19 · 2024: 13 · 2023: 12 · 2022: 11 · 2021: 20 · 2020: 15 · 2019: 25 · 2018: 24 · 2017: 32 · 2016: 24 · 2015: 27 · 2014: 26 · 2013: 26 · 2012: 22
FWCI
32.03
Type
journal article
Language
en
Open access
Locations
  • Antimicrobial Agents and Chemotherapy (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • IRIS (submittedVersion)
  • SERVAL (Université de Lausanne) (submittedVersion)
Funders
Bundesamt für Gesundheit
Topics
  • Health Sciences › Medicine › Infectious Diseases › Antifungal resistance and susceptibility
  • Health Sciences › Medicine › Oncology › Drug Transport and Resistance Mechanisms
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Fungal and yeast genetics research
Keywords
Candida albicans, azole resistance, fluconazole resistance, multidrug transporter, ABC transporters, CDR1, efflux pumps, oropharyngeal candidiasis, AIDS patients, drug accumulation, gene overexpression, benomyl resistance
MeSH terms
Antifungal Agents, Azoles, Base Sequence, Candida albicans, Candidiasis, Oral, DNA, Fungal, Drug Resistance, Microbial, Fungal Proteins, Genes, Fungal, Humans, Microbial Sensitivity Tests, Molecular Sequence Data, Nucleic Acid Hybridization, Plasmids, RNA, Fungal, Saccharomyces cerevisiae, Blotting, Northern, Fluconazole, Polymerase Chain Reaction, AIDS-Related Opportunistic Infections, Drug Resistance, Multiple, ATP-Binding Cassette Transporters, ATP Binding Cassette Transporter, Subfamily B, Member 1, Membrane Transport Proteins

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review