TY - JOUR
T1 - A novel broad allele-specific TaqMan real-time PCR method to detect triazole-resistant strains of aspergillus fumigatus, even with a very low percentage of triazole-resistant cells mixed with triazole-susceptible cells
AU - Wang, Qian
AU - Kontoyiannis, Dimitrios P.
AU - Li, Ruoyu
AU - Chen, Wei
AU - Bu, Dingfang
AU - Liu, Wei
N1 - Funding Information:
This work was supported by the National Science and Technology Major Project for “Major Infectious Diseases Such as AIDS and Viral Hepatitis Prevention and Control Technology Major Projects” (grant 2018ZX10712-001) and “Major New Drugs Innovation and Development” (grant 2017ZX09304028009) and by the National Natural Science Foundation of China (grants 81671990 and 81861148028).
Publisher Copyright:
Copyright © 2019 American Society for Microbiology. All Rights Reserved.
PY - 2019
Y1 - 2019
N2 - Invasive aspergillosis caused by triazole-resistant strains of Aspergillus fumigatus is a growing public health concern, as is the occurrence of mixed infections with triazole-resistant and -susceptible A. fumigatus strains. Therefore, it is crucial to develop robust methods to identify triazole-resistant strains of A. fumigatus, even in mixtures of triazole-resistant and -susceptible strains of A. fumigatus. In this work, we developed a robust, highly selective, and broad-range allele-specific Taq- Man real-time PCR platform consisting of 7 simultaneous assays that detect TR34 (a 34-bp tandem repeat in the promoter region), TR46, G54W (a change of G to W at position 54), G54R, L98H, Y121F, and M220I mutations in the cyp51A gene of A. fumigatus. The method is based on the widely used TaqMan real-time PCR technology and combines allele-specific PCR with a blocking reagent (minor groove binder [MGB] oligonucleotide blocker) to suppress amplification of the wild-type cyp51A alleles. We used this method to detect triazole-resistant clinical strains of A. fumigatus with a variety of cyp51A gene mutations, as well as the triazole-resistant strains in mixtures of triazole-resistant and -susceptible strains of A. fumigatus. The method had high efficiency and sensitivity (300 fg/well, corresponding to about 100 CFU per reaction mixture volume). It could promptly detect triazole resistance in a panel of 30 clinical strains of A. fumigatus within about 6 h. It could also detect cyp51Aassociated resistance alleles, even in mixtures containing only 1% triazole-resistant A. fumigatus strains. These results suggest that this method is robustly able to detect cyp51A-associated resistance alleles even in mixtures of triazole-resistant and -susceptible strains of A. fumigatus and that it should have important clinical applications.
AB - Invasive aspergillosis caused by triazole-resistant strains of Aspergillus fumigatus is a growing public health concern, as is the occurrence of mixed infections with triazole-resistant and -susceptible A. fumigatus strains. Therefore, it is crucial to develop robust methods to identify triazole-resistant strains of A. fumigatus, even in mixtures of triazole-resistant and -susceptible strains of A. fumigatus. In this work, we developed a robust, highly selective, and broad-range allele-specific Taq- Man real-time PCR platform consisting of 7 simultaneous assays that detect TR34 (a 34-bp tandem repeat in the promoter region), TR46, G54W (a change of G to W at position 54), G54R, L98H, Y121F, and M220I mutations in the cyp51A gene of A. fumigatus. The method is based on the widely used TaqMan real-time PCR technology and combines allele-specific PCR with a blocking reagent (minor groove binder [MGB] oligonucleotide blocker) to suppress amplification of the wild-type cyp51A alleles. We used this method to detect triazole-resistant clinical strains of A. fumigatus with a variety of cyp51A gene mutations, as well as the triazole-resistant strains in mixtures of triazole-resistant and -susceptible strains of A. fumigatus. The method had high efficiency and sensitivity (300 fg/well, corresponding to about 100 CFU per reaction mixture volume). It could promptly detect triazole resistance in a panel of 30 clinical strains of A. fumigatus within about 6 h. It could also detect cyp51Aassociated resistance alleles, even in mixtures containing only 1% triazole-resistant A. fumigatus strains. These results suggest that this method is robustly able to detect cyp51A-associated resistance alleles even in mixtures of triazole-resistant and -susceptible strains of A. fumigatus and that it should have important clinical applications.
KW - A. fumigatus
KW - Allele-specific real-time PCR
KW - Cyp51A mutations
KW - Mixed infection
KW - Triazole resistance
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U2 - 10.1128/JCM.00604-19
DO - 10.1128/JCM.00604-19
M3 - Article
C2 - 31315952
AN - SCOPUS:85071710491
SN - 0095-1137
VL - 57
JO - Journal of Clinical Microbiology
JF - Journal of Clinical Microbiology
IS - 9
M1 - e00604-19
ER -