A novel environmental azole resistance mutation in Aspergillus fumigatus and a possible role of sexual reproduction in its emergence

Jianhua Zhang*, Eveline Snelders, Bas J. Zwaan, Sijmen E. Schoustra, Jacques F. Meis, Karin van Dijk, Ferry Hagen, Martha T. van der Beek, Greetje A. Kampinga, Jan Zoll, Willem J.G. Melchers, Paul E. Verweij, Fons Debets

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

30 Citations (Scopus)

Abstract

This study investigated the dynamics of Aspergillus fumigatus azoleresistant phenotypes in two compost heaps with contrasting azole exposures: azole free and azole exposed. After heat shock, to which sexual but not asexual spores are highly resistant, the azole-free compost yielded 98% (49/50) wild-type and 2% (1/50) azole-resistant isolates, whereas the azole-containing compost yielded 9% (4/45) wild-type and 91% (41/45) resistant isolates. From the latter compost, 80% (36/45) of the isolates contained the TR46/Y121F/T289A genotype, 2% (1/45) harbored the TR46/Y121F/M172I/T289A/G448S genotype, and 9% (4/45) had a novel pan-triazoleresistant mutation (TR46 3/Y121F/M172I/T289A/G448S) with a triple 46-bp promoter repeat. Subsequent screening of a representative set of clinical A. fumigatus isolates showed that the novel TR46 3 mutant was already present in samples from three Dutch medical centers collected since 2012. Furthermore, a second new resistance mutation was found in this set that harbored four TR46 repeats. Importantly, in the laboratory, we recovered the TR46 3 mutation from a sexual cross between two TR46 isolates from the same azole-containing compost, possibly through unequal crossing over between the double tandem repeats (TRs) during meiosis. This possible role of sexual reproduction in the emergence of the mutation was further implicated by the high level of genetic diversity of STR genotypes in the azole-containing compost. Our study confirms that azole resistance mutations continue to emerge in the environment and indicates compost containing azole residues as a possible hot spot. Better insight into the biology of environmental resistance selection is needed to retain the azole class for use in food production and treatment of Aspergillus diseases. IMPORTANCE Composting of organic matter containing azole residues might be important for resistance development and subsequent spread of resistance mutations in Aspergillus fumigatus. In this article, we show the dominance of azoleresistant A. fumigatus in azole-exposed compost and the discovery of a new resistance mutation with clinical relevance. Furthermore, our study indicates that current fungicide application is not sustainable as new resistance mutations continue to emerge, thereby threatening the use of triazoles in medicine. We provide evidence that the sexual part of the fungal life cycle may play a role in the emergence of resistance mutations because under laboratory conditions, we reconstructed the resistance mutation through sexual crossing of two azole-resistant A. fumigatus isolates derived from the same compost heap. Understanding the mechanisms of resistance selection in the environment is needed to design strategies against the accumulation of resistance mutations in order to retain the azole class for crop protection and treatment of Aspergillus diseases.

Original languageEnglish
Article numbere00791-17
JournalmBio
Volume8
Issue number3
DOIs
Publication statusPublished - 2017

Fingerprint

Azoles
Aspergillus fumigatus
Reproduction
Mutation
Soil
Genotype
Aspergillus
Tandem Repeat Sequences
Triazoles
Meiosis
Life Cycle Stages
Spores

Keywords

  • Ascospores
  • Aspergillus fumigatus
  • Azole resistance
  • Compost heap
  • Conidiospores
  • Hot spot for resistance development
  • Novel mutation
  • Sexual reproduction

Cite this

Zhang, Jianhua ; Snelders, Eveline ; Zwaan, Bas J. ; Schoustra, Sijmen E. ; Meis, Jacques F. ; van Dijk, Karin ; Hagen, Ferry ; van der Beek, Martha T. ; Kampinga, Greetje A. ; Zoll, Jan ; Melchers, Willem J.G. ; Verweij, Paul E. ; Debets, Fons. / A novel environmental azole resistance mutation in Aspergillus fumigatus and a possible role of sexual reproduction in its emergence. In: mBio. 2017 ; Vol. 8, No. 3.
@article{0b6da4bf111c4d4d9cfad3facc4a29a8,
title = "A novel environmental azole resistance mutation in Aspergillus fumigatus and a possible role of sexual reproduction in its emergence",
abstract = "This study investigated the dynamics of Aspergillus fumigatus azoleresistant phenotypes in two compost heaps with contrasting azole exposures: azole free and azole exposed. After heat shock, to which sexual but not asexual spores are highly resistant, the azole-free compost yielded 98{\%} (49/50) wild-type and 2{\%} (1/50) azole-resistant isolates, whereas the azole-containing compost yielded 9{\%} (4/45) wild-type and 91{\%} (41/45) resistant isolates. From the latter compost, 80{\%} (36/45) of the isolates contained the TR46/Y121F/T289A genotype, 2{\%} (1/45) harbored the TR46/Y121F/M172I/T289A/G448S genotype, and 9{\%} (4/45) had a novel pan-triazoleresistant mutation (TR46 3/Y121F/M172I/T289A/G448S) with a triple 46-bp promoter repeat. Subsequent screening of a representative set of clinical A. fumigatus isolates showed that the novel TR46 3 mutant was already present in samples from three Dutch medical centers collected since 2012. Furthermore, a second new resistance mutation was found in this set that harbored four TR46 repeats. Importantly, in the laboratory, we recovered the TR46 3 mutation from a sexual cross between two TR46 isolates from the same azole-containing compost, possibly through unequal crossing over between the double tandem repeats (TRs) during meiosis. This possible role of sexual reproduction in the emergence of the mutation was further implicated by the high level of genetic diversity of STR genotypes in the azole-containing compost. Our study confirms that azole resistance mutations continue to emerge in the environment and indicates compost containing azole residues as a possible hot spot. Better insight into the biology of environmental resistance selection is needed to retain the azole class for use in food production and treatment of Aspergillus diseases. IMPORTANCE Composting of organic matter containing azole residues might be important for resistance development and subsequent spread of resistance mutations in Aspergillus fumigatus. In this article, we show the dominance of azoleresistant A. fumigatus in azole-exposed compost and the discovery of a new resistance mutation with clinical relevance. Furthermore, our study indicates that current fungicide application is not sustainable as new resistance mutations continue to emerge, thereby threatening the use of triazoles in medicine. We provide evidence that the sexual part of the fungal life cycle may play a role in the emergence of resistance mutations because under laboratory conditions, we reconstructed the resistance mutation through sexual crossing of two azole-resistant A. fumigatus isolates derived from the same compost heap. Understanding the mechanisms of resistance selection in the environment is needed to design strategies against the accumulation of resistance mutations in order to retain the azole class for crop protection and treatment of Aspergillus diseases.",
keywords = "Ascospores, Aspergillus fumigatus, Azole resistance, Compost heap, Conidiospores, Hot spot for resistance development, Novel mutation, Sexual reproduction",
author = "Jianhua Zhang and Eveline Snelders and Zwaan, {Bas J.} and Schoustra, {Sijmen E.} and Meis, {Jacques F.} and {van Dijk}, Karin and Ferry Hagen and {van der Beek}, {Martha T.} and Kampinga, {Greetje A.} and Jan Zoll and Melchers, {Willem J.G.} and Verweij, {Paul E.} and Fons Debets",
year = "2017",
doi = "10.1128/mBio.00791-17",
language = "English",
volume = "8",
journal = "mBio",
issn = "2150-7511",
publisher = "American Society for Microbiology",
number = "3",

}

A novel environmental azole resistance mutation in Aspergillus fumigatus and a possible role of sexual reproduction in its emergence. / Zhang, Jianhua; Snelders, Eveline; Zwaan, Bas J.; Schoustra, Sijmen E.; Meis, Jacques F.; van Dijk, Karin; Hagen, Ferry; van der Beek, Martha T.; Kampinga, Greetje A.; Zoll, Jan; Melchers, Willem J.G.; Verweij, Paul E.; Debets, Fons.

In: mBio, Vol. 8, No. 3, e00791-17, 2017.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - A novel environmental azole resistance mutation in Aspergillus fumigatus and a possible role of sexual reproduction in its emergence

AU - Zhang, Jianhua

AU - Snelders, Eveline

AU - Zwaan, Bas J.

AU - Schoustra, Sijmen E.

AU - Meis, Jacques F.

AU - van Dijk, Karin

AU - Hagen, Ferry

AU - van der Beek, Martha T.

AU - Kampinga, Greetje A.

AU - Zoll, Jan

AU - Melchers, Willem J.G.

AU - Verweij, Paul E.

AU - Debets, Fons

PY - 2017

Y1 - 2017

N2 - This study investigated the dynamics of Aspergillus fumigatus azoleresistant phenotypes in two compost heaps with contrasting azole exposures: azole free and azole exposed. After heat shock, to which sexual but not asexual spores are highly resistant, the azole-free compost yielded 98% (49/50) wild-type and 2% (1/50) azole-resistant isolates, whereas the azole-containing compost yielded 9% (4/45) wild-type and 91% (41/45) resistant isolates. From the latter compost, 80% (36/45) of the isolates contained the TR46/Y121F/T289A genotype, 2% (1/45) harbored the TR46/Y121F/M172I/T289A/G448S genotype, and 9% (4/45) had a novel pan-triazoleresistant mutation (TR46 3/Y121F/M172I/T289A/G448S) with a triple 46-bp promoter repeat. Subsequent screening of a representative set of clinical A. fumigatus isolates showed that the novel TR46 3 mutant was already present in samples from three Dutch medical centers collected since 2012. Furthermore, a second new resistance mutation was found in this set that harbored four TR46 repeats. Importantly, in the laboratory, we recovered the TR46 3 mutation from a sexual cross between two TR46 isolates from the same azole-containing compost, possibly through unequal crossing over between the double tandem repeats (TRs) during meiosis. This possible role of sexual reproduction in the emergence of the mutation was further implicated by the high level of genetic diversity of STR genotypes in the azole-containing compost. Our study confirms that azole resistance mutations continue to emerge in the environment and indicates compost containing azole residues as a possible hot spot. Better insight into the biology of environmental resistance selection is needed to retain the azole class for use in food production and treatment of Aspergillus diseases. IMPORTANCE Composting of organic matter containing azole residues might be important for resistance development and subsequent spread of resistance mutations in Aspergillus fumigatus. In this article, we show the dominance of azoleresistant A. fumigatus in azole-exposed compost and the discovery of a new resistance mutation with clinical relevance. Furthermore, our study indicates that current fungicide application is not sustainable as new resistance mutations continue to emerge, thereby threatening the use of triazoles in medicine. We provide evidence that the sexual part of the fungal life cycle may play a role in the emergence of resistance mutations because under laboratory conditions, we reconstructed the resistance mutation through sexual crossing of two azole-resistant A. fumigatus isolates derived from the same compost heap. Understanding the mechanisms of resistance selection in the environment is needed to design strategies against the accumulation of resistance mutations in order to retain the azole class for crop protection and treatment of Aspergillus diseases.

AB - This study investigated the dynamics of Aspergillus fumigatus azoleresistant phenotypes in two compost heaps with contrasting azole exposures: azole free and azole exposed. After heat shock, to which sexual but not asexual spores are highly resistant, the azole-free compost yielded 98% (49/50) wild-type and 2% (1/50) azole-resistant isolates, whereas the azole-containing compost yielded 9% (4/45) wild-type and 91% (41/45) resistant isolates. From the latter compost, 80% (36/45) of the isolates contained the TR46/Y121F/T289A genotype, 2% (1/45) harbored the TR46/Y121F/M172I/T289A/G448S genotype, and 9% (4/45) had a novel pan-triazoleresistant mutation (TR46 3/Y121F/M172I/T289A/G448S) with a triple 46-bp promoter repeat. Subsequent screening of a representative set of clinical A. fumigatus isolates showed that the novel TR46 3 mutant was already present in samples from three Dutch medical centers collected since 2012. Furthermore, a second new resistance mutation was found in this set that harbored four TR46 repeats. Importantly, in the laboratory, we recovered the TR46 3 mutation from a sexual cross between two TR46 isolates from the same azole-containing compost, possibly through unequal crossing over between the double tandem repeats (TRs) during meiosis. This possible role of sexual reproduction in the emergence of the mutation was further implicated by the high level of genetic diversity of STR genotypes in the azole-containing compost. Our study confirms that azole resistance mutations continue to emerge in the environment and indicates compost containing azole residues as a possible hot spot. Better insight into the biology of environmental resistance selection is needed to retain the azole class for use in food production and treatment of Aspergillus diseases. IMPORTANCE Composting of organic matter containing azole residues might be important for resistance development and subsequent spread of resistance mutations in Aspergillus fumigatus. In this article, we show the dominance of azoleresistant A. fumigatus in azole-exposed compost and the discovery of a new resistance mutation with clinical relevance. Furthermore, our study indicates that current fungicide application is not sustainable as new resistance mutations continue to emerge, thereby threatening the use of triazoles in medicine. We provide evidence that the sexual part of the fungal life cycle may play a role in the emergence of resistance mutations because under laboratory conditions, we reconstructed the resistance mutation through sexual crossing of two azole-resistant A. fumigatus isolates derived from the same compost heap. Understanding the mechanisms of resistance selection in the environment is needed to design strategies against the accumulation of resistance mutations in order to retain the azole class for crop protection and treatment of Aspergillus diseases.

KW - Ascospores

KW - Aspergillus fumigatus

KW - Azole resistance

KW - Compost heap

KW - Conidiospores

KW - Hot spot for resistance development

KW - Novel mutation

KW - Sexual reproduction

U2 - 10.1128/mBio.00791-17

DO - 10.1128/mBio.00791-17

M3 - Article

VL - 8

JO - mBio

JF - mBio

SN - 2150-7511

IS - 3

M1 - e00791-17

ER -