Population structure and diversity of the pathogenic fungus Aspergillus fumigatus isolated from different sources and geographic origins

Abstract

Fifty-five clinical and environmental

Phenotypic characteristics of isolates of Aspergillus section Fumigatifrom different geographic origins and their relationships with genotypic characteristics

“…This is contrary to what is observed when analyzing the genotypical characteristics, where the majority of the isolates separate according to geographic origin [21]. This confirms that these molecular markers are more sensible to the discrimination between isolates by geographic origin.…”

“…In Latin American countries, not much research has been done to establish their phenotypic and genotypic variability. To provide more information regarding this fungus, we studied the phenotypic characteristics (the micro- and macromorphology, size of the conidia, vesicles size, thermotolerance and antifungal susceptibility) of clinical and environmental isolates of A. fumigatus from MX, AR, PE and FR, and we assessed the relationship between the phenotypic and the genotypic characteristics reported in the literature for these isolates [21], to determine whether the variability of the phenotypic characteristics correlated with the genotypic characteristics. The phenotypic characterization was not different from that reported for the specie; however, some interesting observations are worth highlighting concerning the size of the vesicles, thermotolerance and growth rate at different temperatures (28, 37 and 48°C).…”

“…Pairwise distances among isolates were estimated with Euclidean distance index [27] and a dendrogram was constructed by the Unweighted Pair Group Method with Arithmetic Averages (UPGMA). However, to obtain a best relationship among isolates, we also integrated in a single matrix the phenotypic data obtained in this study and genotypic data (AFLP) reported by Duarte-Escalante et al [21] of the same isolates (data not shown). A dendrogram of this data set was constructed by UPGMA.…”

“…Given these findings, in this study the phenotypic variation was analyzed in isolates of A . section Fumigati from Mexico (MX), Argentina (AR), Peru (PE) and France (FR) to find associations between the phenotypic characteristics (the micro- and macromorphology, size of conidia, size vesicles, thermotolerance and susceptibility to antifungal) and the geographic origin of these isolates, as well as to determine the correlation between these traits and previously reported genotypes that were generated by AFLP (Amplified Fragment Length Polymorphism) [21]. …”

On the evolution of azole resistance in Aspergillus fumigatus

“…Genotype analysis based on microsatellite loci shows enormous diversity in TR34, TR46, and TR46 3 isolates, which makes it difficult to conclude the possible evolutionary route of these TR variants (Debeaupuis et al 1997;Duarte-Escalante et al 2009;Araujo et al 2010). It is generally believed that the microsatellite alleles and mating-type remain unchanged via asexual reproduction, and even after sexual reproduction (just shuffling genes rather than changing), therefore it is difficult to explain the origin of highly diverse microsatellite loci.…”