Molds of genus Aspergillus is ubiquitous in the environment. Individuals typically inhale hundreds of conidia per day. For the vast majority of people, their defense systems are able to easily remove fungi from lungs. If immunocompromised people inhale the conidia of Aspergillus fumigatus, invasive aspergillosis may occur. The most commonly used drugs to treat aspergillosis are azoles. Owing to the frequent use of azoles in agriculture, more resistant A. fumigatus isolates against azoles occur in nature. The aim of my master's thesis is to determine the prevalence of azole-resistant A. fumigatus isolates in soil samples from organic farms and horticultural plantations. A. fumigatus sensu lato strains were isolated on basic mycological media. Sensitivity to azoles was determined by VIPcheckTM screening test. We were sought to molecularly demonstrate the presence of the TR34/L98H mutation on resistant strains. 153 different samples were tested, of which A. fumigatus was isolated from 103 samples. Of this 103 samples, we found 3 resistant isolates using the VIPcheckTM method (two against itraconazole and one against voriconazole). All three isolates came from horticultural plantation Mozirski gaj. All three supposedly resistant isolates were tested for sensitivity using a gradient diffusion method to obtain data on the minimum inhibitory concentration. With this method, only one sample proved to be resistant to itraconazole and posaconazole. We tested all three samples with a molecular methode (a real time PCR). An isolate, that showed azole resistance by a gradient diffusion method carries a mutation in the cyp51A gene, TR34/L98H.
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