Genotypic characterization of sequential Aspergillus fumigatus isolates from patients with cystic fibrosis

Abstract

Twenty-three sequential Aspergillus fumigatus sputum isolates, which had been collected over a period of 2 years, from two patients with cystic fibrosis were genotyped by random amplified polymorphic DNA PCR and restriction fragment length polymorphism analysis. In patient B, one genotype was predominantly present in the sputum samples, while in the other patient up to nine different genotypes were identified. This study suggests that different patterns of colonization with A. fumigatus exist in patients with cystic fibrosis.

New restriction fragment length polymorphism (RFLP) markers for Aspergillus fumigatus

“…Genotyping of A. fumigatus isolates from patients with invasive aspergillosis strongly suggests that patients are often colonized and infected by a unique strain [6,18]. However, Verweij et al [19] have documented that di¡erent patterns of colonization with A. fumigatus can exist in patients with cystic ¢brosis. Our study indicates that the patients were infected with genetically unrelated strains during the course of their illness.…”

Molecular typing of Aspergillus species

“…This probe, called Afut1, possesses specific characteristics of a retrotransposon-like element 33 and has been used in most RFLP studies so far. 6,14,34 Other probes used for fingerprinting of A. fumigatus, which are based on retrotransposon-like elements are Afut2 35 and Af4A. 36 McAlphin et al constructed and characterised a species-specific probe for A. flavus named pAF28.…”

“…96 To visualise the colonisation pattern of Aspergillus isolates in CF patients, several studies where sequential isolates were typed, have been performed. Verweij et al [14] presented two CF patients with A. fumigatus isolates cultured in sequential sputum samples over a period of 2 years, which were analysed with Afut1-RFLP and RAPD. The fingerprints of these samples showed three different genotypes in 11 samples for one patient, of which one genotype was predominantly present in the sputum samples.…”

“…The results of these studies are in agreement, CF patients appeared to have different patterns of colonisation with A. fumigatus, as analysis of sequential isolates showed that some CF patients exhibited a predominant genotype and others had multiple genotypes. 14,88,97 In most of the CF patients airway colonisation with A. fumigatus seems to be a recurrent event. The repeated isolation of one unique genotype in these patients does not necessarily forecast the occurrence of aspergillosis.…”

“…By typing the cultured isolates from sequential sputum samples, one can evaluate whether the colonisation of the respiratory tract is because of one or several isolates or because of frequent recolonisations. 14 The genetic diversity in patients with IA can also be investigated to visualise the dissemination routes of isolates from the respiratory tract to the lung tissue and other organs. 2,15 Several phenotypic and genotypic studies have been used to distinguish among the individual Aspergillus isolates.…”