國家衛生研究院 NHRI:Item 3990099045/14342

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Title:	A predominant genotype of azole-resistant Candida tropicalis clinical strains
Authors:	Tseng, KY;Liao, YC;Chen, FC;Chen, FJ;Lo, HJ
Contributors:	National Institute of Infectious Diseases and Vaccinology;Institute of Population Health Sciences
Abstract:	Through the Taiwan Surveillance of Antimicrobial Resistance of Yeasts (known as TSARY), we found that Candida tropicalis was not the most common non-albicans Candida species, but C tropicalis does have a higher fluconazole-resistant rate than other Candida species. We detected that 45·3% (24/53) of fluconazole-non-susceptible C tropicalis collected in 1999 and 2006 belonged to the same cluster: clade 5; according to the multi-locus sequence typing method. We found that 9·2% (56/608) of C tropicalis from 2014 and 2018 were resistant to fluconazole. 94·6% (53/56) of fluconazole-resistant C tropicalis were genetically closely related and belonged to clade 4, rather than clade 5. A combination of mutation and overexpression of ERG11 was the major mechanism that contributed to the drug resistance of clade 4.1. Multi-locus sequence typing is a convenient and cost-effective tool for studying the genetic relatedness and genetic diversity of isolates. Nevertheless, the method might have some limitations as it evaluates DNA fragments of maximum six genes only. In the present study, to assess the data from multi-locus sequence typing, we compared the mitochondrial genome sequence of 34 tested clinical isolates. Despite different drug susceptibilities, the genetic relatedness of the two clusters as identified by multi-locus sequencing, was confirmed by the mitochondrial genome sequence (appendix). Hence, multi-locus sequencing is still a viable approach for rapidly identifying the genetic relatedness among C tropicalis isolates. Our preliminary data showed that 87·0% (40/46) of fluconazole-susceptible clade 5 isolates had high fluconazole minimum inhibtory concentrations after longer incubation. Therefore, the clade 5 isolates could survive in the presence of low levels of fluconazole and might be prone to fluconazole resistance. An outbreak of Candida auris in a neuroscientific intensive care unit in the UK was linked to reusable axillary temperature probes.2 Among 21 C tropicalis isolates from patients in Italy, nine belonged to the genotype DST747 and six belonged to DST333. Isolates from hospital environments and the hands of health-care workers also belonged to either of these two DST genotypes.3 Therefore, a specific Candida species clone can persist in the environment and be horizontally transmitted within a health-care setting. In addition to our findings, 23 of the 30 (76·7%) fluconazole-resistant C tropicalis from China belonged to clade 4.4 Hence, active surveillance to detect the emergence and dissemination of azole-resistant C tropicalis in clinical, hospital, and community environments might help us to elucidate how these resistant isolates spread in the wild and how they persist, which could help to prevent further spread of clade 4.
Date:	2022-09
Relation:	Lancet Microbe. 2022 Sep;3,(9):Article number e646.
Link to:	http://dx.doi.org/10.1016/s2666-5247(22)00179-3
JIF/Ranking 2023:	http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=NHRI&SrcApp=NHRI_IR&KeyISSN=2666-5247&DestApp=IC2JCR
Cited Times(WOS):	https://www.webofscience.com/wos/woscc/full-record/WOS:000898604500007
Cited Times(Scopus):	https://www.scopus.com/inward/record.url?partnerID=HzOxMe3b&scp=85137653189
Appears in Collections:	[Feng-Jui Chen] Periodical Articles [Hsiu-Jung Lo] Periodical Articles [Feng-Chi Chen] Periodical Articles [Yu-Chieh Liao] Periodical Articles

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