Molecular epidemiology of airway colonisation by Aspergillus fumigatus in cystic fibrosis patients

A total of 109 sequential and multiple Aspergillus fumigatus isolates corre sponding to 41 samples from seven cystic fibrosis (CF) patients was typed b y random amplification of polymorphic DNA (RAPD) with the primer NS3 from t he fungal ribosomal gene 18S subunit, and by sequence-specific DNA primer ( SSDP) analysis. RAPD typing of the isolates revealed 10 different genotypes , whereas nine genotypes were identified by SSDP, Combination of the two ty ping methods permitted the differentiation of 25 overall genotypes, The col onisation typing patterns differed greatly between patients colonised for < 1 year by A. fumigatus and long-term colonised patients. Two of three recen tly colonised patients presented a large number of types even in the same s ample, unlike the chronically colonised patients, who harboured a limited n umber of genotypes, In the latter, the occurrence of a dominant genotype, u sually the overall genotype 2, tended to reflect to the duration of colonis ation. Moreover, anti-catalase antibodies to A. fumigatus appeared in most cases to be in response to genotype 2, These findings suggest that some str ains of A, fumigatus may be selected during prolonged colonisation of the a irways in CF patients.