Azole resistance in<i>Candida albicans</i>

Smith, Kalie; Warnock, David W.; Kennedy, C. T. C.; Johnson, Elizabeth; Hopwood, V.; Cutsem, J. Van; Bossche, H. Vanden

doi:10.1080/02681218680000201

Cited by 91 publications

(63 citation statements)

References 15 publications

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“…Two of them, ATCC 28516 and ATCC 44858, were extensively used in previous biochemical studies (Vanden Bossche et al, 1980) and were azolesensitive. The seven other strains were azole resistant : NCPF 3363 (Smith et al, 1986) was isolated from a patient suffering from chronic mucocutaneous candidiasis (CMC) ; J913004\I was isolated in France from an AIDS patient ; B59626 and B59630 were sequential isolates from an AIDS patient in Germany, strains C40 and C26 were isolated from AIDS patients with oropharyngeal candidiasis and maintained at the Institute of Microbiology, Centre Hospital Universitaire Vaudois, Switzerland (Sanglard et al, 1995) ; strain 6406\8 was a spontaneous, laboratory-derived polyene-resistant mutant of strain 6406 and was obtained from Dr D. Kerridge, University of Cambridge. The identity of the isolates as C. albicans was confirmed by standard procedures.…”

Section: Methodsmentioning

confidence: 99%

“…Then the suspension was immediately homogenized in a Bead-Beater as described above. The homogenate was differentially centrifuged for 5 min at 1500 g, 20 min at 10 000 g and 1 h at 100 000 g. The pellet thus obtained was resuspended in 0n05 M potassium phosphate buffer containing 0n01 M EDTA (pH 7n4) and the suspension was recentrifuged for 1 h at 100 000 g (Vanden Bossche et al, 1986). The final pellet was resuspended in 0n1 M potassium phosphate buffer (pH 7n4).…”

Section: Methodsmentioning

confidence: 99%

“…Microsomes were isolated from C. albicans as described previously (Vanden Bossche et al, 1986). In summary, C. albicans cells, grown in semianaerobic conditions, were harvested by centrifugation, then washed and resuspended in ice-cold 0n65 M mannitol.…”

Section: Methodsmentioning

confidence: 99%

“…The final pellet was resuspended in 0n1 M potassium phosphate buffer (pH 7n4). The P-450 content and the effects of azoles on the interaction of CO with the reduced haem iron of P-450 were measured as described previously (Vanden Bossche et al, 1986).…”

Section: Methodsmentioning

confidence: 99%

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Contribution of mutations in the cytochrome P450 14α-demethylase (Erg11p, Cyp51p) to azole resistance in Candida albicans

et al. 1999

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The cytochrome P450 14α-demethylase, encoded by the ERG11 (CYP51) gene, is the primary target for the azole class of antifungals. Changes in the azole affinity of this enzyme caused by amino acid substitutions have been reported as a resistance mechanism. Nine Candida albicans strains were used in this study. The ERG11 base sequence of seven isolates, of which only two were azole-sensitive, were determined. The ERG11 base sequences of the other two strains have been published previously. In these seven isolates, 12 different amino acid substitutions were identified, of which six have not been described previously (A149V, D153E, E165Y, S279F, V452A and G465S). In addition, 16 silent mutations were found. Two different biochemical assays, subcellular sterol biosynthesis and CO binding to reduced microsomal fractions, were used to evaluate the sensitivity of the cytochromes for fluconazole and itraconazole. Enzyme preparations from four isolates showed reduced itraconazole susceptibility, whereas more pronounced resistance to fluconazole was observed in five isolates. A three-dimensional model of C. albicans Cyp51p was used to position all 29 reported substitutions, 98 in total identified in 53 sequences. These 29 substitutions were not randomly distributed over the sequence but clustered in three regions from amino acids 105 to 165, from 266 to 287 and from 405 to 488, suggesting the existence of hotspot regions. Of the mutations found in the two N-terminal regions only Y132H was demonstrated to be of importance for azole resistance. In the Cterminal region three mutations are associated with resistance, suggesting that the non-characterized substitutions found in this region should be prioritized for further analysis.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Contribution of mutations in the cytochrome P450 14α-demethylase (Erg11p, Cyp51p) to azole resistance in Candida albicans

et al. 1999

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“…A few strains have been reported to be isolated from CMCC patients (17,23). To our knowledge, however, only one strain, the C. albicans NCPF3363 strain, has been analyzed in detail for the molecular mechanisms of azole resistance (4,8).…”

Section: Discussionmentioning

confidence: 99%

Characterization of Mechanisms of Fluconazole Resistance in a Candida albicans Isolate from a Japanese Patient with Chronic Mucocutaneous Candidiasis

Kamai

Maebashi

Kudoh

et al. 2004

Microbiology and Immunology

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We examined the mechanisms of fluconazole resistance in a fluconazole‐resistant Candida albicans isolate from a Japanese patient with chronic mucocutaneous candidiasis. It was demonstrated that the highly resistant phenotype of this strain was associated with combined mechanisms of the energy‐dependent reduced intracellular accumulation of fluconazole, presumably due to the increased expression of the ATP‐binding cassette efflux pump CDR gene(s), and the reduced affinity of the target enzyme, Erg11p, to fluconazole. In particular, the reduced affinity of Erg11p was considered to contribute largely to the fluconazole resistance in the TIMM3209 strain. Biochemical studies indicated that the Erg11p from the TIMM3209 strain showed reduced susceptibility both to fluconazole and itraconazole of cell‐free ergosterol biosynthesis, and cytochrome P‐450 also showed reduced affinity to fluconazole in the carbon monoxide‐cytochrome P‐450 complex formation assay. We identified two amino acid substitutions, Y132H and G448V, in Erg11p from the TIMM3209 strain. We found that the cytochrome P‐450 from the TIMM3209 strain decayed during incubation at 37 C without fluconazole although it is unknown whether or not the phenomenon is linked to the resistant phenotype. These mutations are thought to confer the above‐mentioned characteristics to Erg11p.

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Thrush Can Be Prevented in Patients With Acquired Immunodeficiency Syndrome and the Acquired Immunodeficiency Syndrome—Related Complex

Stevens¹

1991

Arch Intern Med

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Azole resistance inCandida albicans

Cited by 91 publications

References 15 publications

Contribution of mutations in the cytochrome P450 14α-demethylase (Erg11p, Cyp51p) to azole resistance in Candida albicans

Contribution of mutations in the cytochrome P450 14α-demethylase (Erg11p, Cyp51p) to azole resistance in Candida albicans

Characterization of Mechanisms of Fluconazole Resistance in a Candida albicans Isolate from a Japanese Patient with Chronic Mucocutaneous Candidiasis

Thrush Can Be Prevented in Patients With Acquired Immunodeficiency Syndrome and the Acquired Immunodeficiency Syndrome—Related Complex

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