Amino acid substitutions in the Candida albicans sterol 5,6-desaturase (Erg3p) confer azole resistance: characterization of two novel mutants with impaired virulence
| Autor: | Claire Lacroix, Fabrice Pagniez, Patrice Le Pape, Michel Miegeville, Florent Morio |
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| Přispěvatelé: | Cibles et médicaments de l'infection, de l'immunité et du cancer (IICiMed), Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN), Laboratoire de Parasitologie-Mycologie (Institut de biologie, CHU de Nantes), Centre hospitalier universitaire de Nantes (CHU Nantes), Hopital Saint-Louis [AP-HP] (AP-HP), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Laboratoire de Parasitologie-Mycologie, Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Henri Mondor-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12) |
| Rok vydání: | 2012 |
| Předmět: |
Hyphal growth
Antifungal Agents Drug resistance Mice chemistry.chemical_compound C. albicans [SDV.MHEP.MI]Life Sciences [q-bio]/Human health and pathology/Infectious diseases Amphotericin B Candida albicans Pharmacology (medical) azole antifungals Fluconazole chemistry.chemical_classification Ergosterol Virulence biology Candidiasis Middle Aged amphotericin B ERG3 Sterols Infectious Diseases Female Oxidoreductases medicine.drug Adult Microbiology (medical) Microbial Sensitivity Tests ergosterol biosynthesis Chemoprevention Gas Chromatography-Mass Spectrometry Microbiology Drug Resistance Fungal medicine Animals Humans [SDV.BBM]Life Sciences [q-bio]/Biochemistry Molecular Biology Pharmacology Gene Expression Profiling Cell Membrane Triazoles biology.organism_classification Pyrimidines Amino Acid Substitution chemistry Azole Mutant Proteins [SDV.SPEE]Life Sciences [q-bio]/Santé publique et épidémiologie Voriconazole |
| Zdroj: | Journal of Antimicrobial Chemotherapy Journal of Antimicrobial Chemotherapy, Oxford University Press (OUP), 2012, 67 (9), pp.2131-2138. ⟨10.1093/jac/dks186⟩ |
| ISSN: | 1460-2091 0305-7453 |
| Popis: | Objectives To determine the mechanisms responsible for fluconazole resistance in two Candida albicans isolates (CAAL2 and CAAL76) recovered from two hospitalized patients after fluconazole prophylaxis. Methods MICs of fluconazole and voriconazole were determined by the broth microdilution method (CLSI M27-A3), and by Etest(®) for amphotericin B. RNA expression levels of CDR1, MDR1 and ERG11 were determined by RT-PCR. Mutations in ERG11 and ERG3 were investigated by amplification and sequencing. Sterol membrane profiles were determined by gas chromatography-mass spectrometry (GC-MS). In vivo virulence was determined in a murine model of invasive candidiasis. Results Both isolates displayed azole cross-resistance and reduced susceptibility to amphotericin B, and are novel Δ(5,6)-desaturase (Erg3p) mutants. CAAL2 harbours a new amino acid substitution (L193R), whereas a 13 bp deletion leading to a truncated Erg3p (Δ366-378) was found in CAAL76. Both genetic alterations impaired Erg3p function as shown by GC-MS in these isolates (ergosterol content below 10%, and accumulation of ergosta-7,22-dienol above 40%). In vivo, in a murine model of invasive candidiasis, both CAAL2 and CAAL76 exhibited a significant trend toward reduced virulence, which seems to be linked to a reduced capacity for hyphal growth. Conclusions These findings demonstrate the critical role of residue 193 in Erg3p function and azole resistance. We suggest that this attenuated in vivo virulence phenotype could be linked to lower potential for hyphal growth. Taken together, our findings highlight the fact that erg3 mutants must be considered in future studies aiming at investigating azole antifungal drug resistance. |
| Databáze: | OpenAIRE |
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