Genetic diversity of clinical and environmental strains of Aspergillus fumigatus by microsatellite typing

Ricardo Araujo1, Leonor Gusmao1, Acacio G Rodrigues2, Cidalia Pina-Vaz2, Antonio Amorim3

Author address: 

1IPATIMUP, University of Porto, Porto, Portugal, 2Dept. Microbiology, Faculty of Medicine, University of Porto, Porto, Portugal, 3Faculty of Science, University of Porto, Porto, Portugal


De Valk et al. had previously developed a three multiplex panel with nine short tandem repeats (STR) showing a discriminatory power of 99.94% among A. fumigatus strains. We had improved this fingerprint reaction by developing a single multiplex with even higher discriminatory power (three new STR were included). The new method was tested in clinical and environmental strains of A. fumigatus and the genotype frequencies in both groups were compared. Ninety-two strains of A. fumigatus (47 clinical versus 45 environmental strains) were selected from a local collection. Following DNA extraction, a single multiplex with eight primer pairs (forward primers labelled with 6-FAM, PET, NED or VIC) was performed in a Genetic Analyzer ABI Prism 3100. Sequencing was further performed for the characterization of the different STR alleles structure. The multiplex was performed successfully and an excellent discrimination power was found (all strains were different). The markers resulted in high genetic diversity from 11 (marker 7) to 32 (marker 1) different genotypes. Tri- and pentanucleotide repeat motifs were responsible for higher diversity values when compared to tetranucleotide repeats. The association test between all pairs of markers showed that 3 out of a total of 28 comparisons were significantly deviated from randomness. No significant differences were found between the genotypes of clinical and environmental strains (99.3% of the variation was within populations). Thus, both populations show a probable similar pathogenic potentia

abstract No: 


Full conference title: 

    • ECFG 9th (2008)