Aspergillus fumigatus is an opportunistic fungus known to cause a group of life-threatening infections collectively known as aspergillosis. In this thesis, multilocus sequence and microsatellite markers, among others, were used to study global and local A. fumigatus population structures. We examined the roles of sexual and asexual reproduction in the initiation of azole resistance globally. Furthermore, we investigated the origin of multi-triazole resistance in India and whether the use of fungicides on farms propagates resistance in environmental strains of clinical importance in Hamilton, Ontario. We characterized for the first time the A. fumigatus population in Cameroon while concomitantly screening for environmental resistance. Our results showed that sexual reproduction plays a key role in the development of triazole resistance globally. We found that multi-triazole resistance in India has multiple origins, which include mutational, recombinational and exotic origins. Our results provided little to no evidence that azole fungicides are the origin, or increase the frequency of triazole resistance in clinical A. fumigatus in Hamilton. Additionally, we identified a significantly unique A. fumigatus population in Cameroon. Our findings will potentially contribute towards developing effective long-term management strategies against aspergillosis. / Thesis / Doctor of Philosophy (PhD) / Aspergillus fumigatus is a mold capable of causing severe infection in humans. Infections caused by A. fumigatus can often be treated using antifungals. However, there have been several reported cases of treatment failure around the world over the last two decades. Generally speaking, treatment failure in patients is often associated with antifungal resistance in A. fumigatus. My thesis aims at better understanding the distribution and investigating the origin of resistance in A. fumigatus at both global and local levels. Here, we analyze A. fumigatus strains from 15 countries, including strains from Hamilton, Ontario. Our findings will potentially contribute towards establishing effective long-term management strategies against A. fumigatus infections locally and globally.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/22246 |
| Date | 11 1900 |
| Creators | Ashu, Eta |
| Contributors | Xu, Jianping, Biology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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