These authors contributed equally to this work.
Evidence for genetic differentiation and variable recombination rates among Dutch populations of the opportunistic human pathogen Aspergillus fumigatus
Article first published online: 22 NOV 2011
© 2011 Blackwell Publishing Ltd
Volume 21, Issue 1, pages 57–70, January 2012
How to Cite
KLAASSEN, C. H. W., GIBBONS, J. G., FEDOROVA, N. D., MEIS, J. F. and ROKAS, A. (2012), Evidence for genetic differentiation and variable recombination rates among Dutch populations of the opportunistic human pathogen Aspergillus fumigatus. Molecular Ecology, 21: 57–70. doi: 10.1111/j.1365-294X.2011.05364.x
- Issue published online: 19 DEC 2011
- Article first published online: 22 NOV 2011
- Received 26 January 2011; revision received 28 September 2011; accepted 10 October 2011
- microbial biology;
- molecular evolution;
- population genetics;
- azole resistance;
- Aspergillus fumigatus
As the frequency of antifungal drug resistance continues to increase, understanding the genetic structure of fungal populations, where resistant isolates have emerged and spread, is of major importance. Aspergillus fumigatus is an ubiquitously distributed fungus and the primary causative agent of invasive aspergillosis (IA), a potentially lethal infection in immunocompromised individuals. In the last few years, an increasing number of A. fumigatus isolates has evolved resistance to triazoles, the primary drugs for treating IA infections. In most isolates, this multiple-triazole-resistance (MTR) phenotype is caused by mutations in the cyp51A gene, which encodes the protein targeted by the triazoles. We investigated the genetic differentiation and reproductive mode of A. fumigatus in the Netherlands, the country where the MTR phenotype probably originated, to determine their role in facilitating the emergence and distribution of resistance genotypes. Using 20 genome-wide neutral markers, we genotyped 255 Dutch isolates including 25 isolates with the MTR phenotype. In contrast to previous reports, our results show that Dutch A. fumigatus genotypes are genetically differentiated into five distinct populations. Four of the five populations show significant linkage disequilibrium, indicative of an asexual reproductive mode, whereas the fifth population is in linkage equilibrium, indicative of a sexual reproductive mode. Notably, the observed genetic differentiation among Dutch isolates does not correlate with geography, although all isolates with the MTR phenotype nest within a single, predominantly asexual, population. These results suggest that both reproductive mode and genetic differentiation contribute to the structure of Dutch A. fumigatus populations and are probably shaping the evolutionary dynamics of drug resistance in this potentially deadly pathogen.