Molecular characterization and sterol profiles identify nonsynonymous mutations in ERG2 as a major mechanism conferring reduced susceptibility to amphotericin B in candida kefyr

Asadzadeh, Mohammad, Alfouzan, Wadha, Parker, Josie E., Meis, Jacques F., Kelly, Steven L., Joseph, Leena, Ahmad, Suhail and Alanio, Alexandre 2023. Molecular characterization and sterol profiles identify nonsynonymous mutations in ERG2 as a major mechanism conferring reduced susceptibility to amphotericin B in candida kefyr. Microbiology Spectrum 11 (4) , e01474-23. 10.1128/spectrum.01474-23

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Abstract

The molecular basis of reduced susceptibility to amphotericin B (rs-AMB) among any yeasts is poorly defined. Genetic alterations in genes involved in ergosterol biosynthesis and total cell sterols were investigated among clinical Candida kefyr isolates. C. kefyr isolates (n = 81) obtained from 74 patients in Kuwait and identified by phenotypic and molecular methods were analyzed. An Etest was initially used to identify isolates with rs-AMB. Specific mutations in ERG2 and ERG6 involved in ergosterol biosynthesis were detected by PCR sequencing. Twelve selected isolates were also tested by the SensiTitre Yeast One (SYO), and total cell sterols were evaluated by gas chromatography-mass spectrometry and ERG3 and ERG11 sequencing. Eight isolates from 8 patients showed rs-AMB by Etest, including 2 isolates with additional resistance to fluconazole or to all three antifungals. SYO correctly identified 8 of 8 rs-AMB isolates. A nonsynonymous mutation in ERG2 was detected in 6 of 8 rs-AMB isolates but also in 3 of 73 isolates with a wild-type AMB pattern. One rs-AMB isolate contained a deletion (frameshift) mutation in ERG2. One or more nonsynonymous mutations was detected in ERG6 in 11 of 81 isolates with the rs-AMB or wild-type AMB pattern. Among 12 selected isolates, 2 and 2 isolates contained a nonsynonymous mutation(s) in ERG3 and ERG11, respectively. Ergosterol was undetectable in 7 of 8 rs-AMB isolates, and the total cell sterol profiles were consistent with loss of ERG2 function in 6 rs-AMB isolates and loss of ERG3 activity in another rs-AMB isolate. Our data showed that ERG2 is a major target conferring rs-AMB in clinical C. kefyr isolates.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Biosciences
Publisher:	American Society for Microbiology
ISSN:	2165-0497
Date of First Compliant Deposit:	12 July 2023
Date of Acceptance:	1 June 2023
Last Modified:	28 Sep 2023 19:17
URI:	https://orca.cardiff.ac.uk/id/eprint/160985

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