Novel Mechanisms of Antifungal Resistance in Aspergillus fumigatus

Abstract

Abstract Globally there are more than a billion individuals affected by fungal disease with an annual mortality of ~1.5 million. There are few antifungal drugs. The azole class of antifungal is commonly used to treat Aspergillus fumigatus, but resistance is increasing. This project aims to uncover important and novel mechanisms of azole drug resistance. Recently, a genome scale mutagenesis experiment identified a number of genes that were associated with altered azole sensitivity. These genes include; a number of major facilitator superfamily (MFS) and ATP-binding cassette (ABC) transporters, tRNA and tRNA modification enzymes. Few previous studies have determined a role for ABC and MFS azole transporters in azole resistance in A. fumigatus. Eleven knockouts were generated based on the transposon mutagenesis results. Knockouts were tested for minimal inhibitory concentration (MIC), growth rate on solid media, and gene expression under Itraconazole (ITZ). Five knockouts grew significantly faster in the presence of ITZ compared to the parental isolate. Four of the MFS genes were up-regulated under ITZ exposure. One ABC transporter showed higher growth than A1160 under all ITZ at 0.12, 0.5 mg/L with P values 0.01, 0.04.One MFS transporter showed characteristics of being an azole importer. This gene(AziA) was deleted. Increased growth (11.5 fold) was observed for the ΔAziA strain on ITZ plates, peaking at 0.5mg/L (P

Date of Award	1 Aug 2019
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Michael Bromley (Supervisor) & Paul Bowyer (Supervisor)