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Examination of cyp51A and cyp51B expression level of the first Polish azole resistant clinical Aspergillus fumigatus isolate

100%

Brillowska-Dąbrowska A., Mroczyńska M., Nawrot U., Włodarczyk K., Kurzyk E.

Acta Biochimica Polonica

2015

vol. 62

issue 4

837-839

Aspergillus fumigatus is one of the most prevalent airborne fungal pathogens causing infections worldwide. Most A. fumigatus strains are susceptible to azoles, which are administered as the first line therapeutics. However, during last decade the acquired resistance to triazoles by these species has been described. There is a number of publications concerning the examination of clinical A. fumigatus strains from different countries, however there has been no report from Poland. Here, we describe for the first time, an examination of cyp51A and cyp51B expression level of 11 clinical A. fumigatus strains isolated during 2007-2014 period from the collection of Medical University in Wrocław. Their susceptibility to itraconazole, voriconazole and posaconazole has been examined. The MIC values of triazoles for one of the examined isolates were respectively: > 8 mg/L for itraconazole, 2 mg/L for voriconazole and 0.5 mg/L for posaconazole. The cyp51A gene with its promoter region of all isolates was sequenced. It was found that the resistant isolate harbors the TR34/L98H mutation in the cyp51A gene and when cultured on media supplemented with voriconazole exhibits overexpression of both, cyp51A and cyp51B genes. The level of cyp51A gene expression was about 50 times higher than cyp51B.

Relation of the polymorphism of cyp51A sequence and the susceptibility of Aspergillus fumigatus isolates to triazoles determined by commercial gradient test (Etest) and by reference methods

73%

Nawrot U., Sulik-Tyszka B., Kurzyk E., Mroczyńska M., Włodarczyk K., Wróblewska M., Basak G., Brillowska-Dąbrowska A.

Acta Biochimica Polonica

2017

vol. 64

issue 4

631-634

The aim of this study was to evaluate the accuracy of commercial gradient test (Etest) in the detection of triazole resistant Aspergillus fumigatus isolates using reference microdilution methods and the analysis of sequences of the cyp 51A gene. The study was performed on twenty clinical isolates which were identified as Aspergillus fumigatus based on the DNA sequences of the ITS1-2 fragment of ribosomal DNA and the β-tubulin gene, out of them seventeen isolates showed wild-type cyp51A sequence and three were positive for the mutation TR34/L98H. All isolates were tested for the susceptibility to itraconazole (ITZ), voriconazole (VOR) and posaconasole (POS) using microdilution methods, according to EUCAST and CLSI protocols, as well as using Etest. The results of microdilution and Etests were analysed separately according to clinical breakpoints (CBP) defined by EUCAST version 7.0 and epidemiological cut off values (ECV). Etest as well as reference methods excellently recognised the WT isolates, which were susceptible to all tested triazoles, regardless of the method and CBP or ECV criteria used. The Etest recognized three non-WT isolates as resistant or intermediately sensitive to ITZ and POS and one as resistant to VOR. The categorical concordance between Etests and EUCAST and Etests and the CLSI method ranged from 90 to 100%. The interpretation of the results obtained from routine A. fumigatus Etests requires great caution. The use of the confirmative examinations with reference AST methods as well as with molecular tests is recommended.

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2 Acta Biochimica Polonica

1 2017

1 2015

2 Brillowska-Dąbrowska A.

2 Kurzyk E.

2 Mroczyńska M.

2 Nawrot U.

2 Włodarczyk K.

1 Basak G.

1 Sulik-Tyszka B.

1 Wróblewska M.

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Examination of cyp51A and cyp51B expression level of the first Polish azole resistant clinical Aspergillus fumigatus isolate

Relation of the polymorphism of cyp51A sequence and the susceptibility of Aspergillus fumigatus isolates to triazoles determined by commercial gradient test (Etest) and by reference methods