Value of different methods for the characterisation of Aspergillus terreusstrains

To evaluate different methods for strain differentiation, 10 isolates of As pergillus terreus from Germany and two epidemiologically unrelated strains were investigated. The sources of the isolates were patients with cystic fi brosis (4), immunosuppression (2), otitis externa (2), sinusitis (1) and en docarditis (1), Environmental isolates were obtained from a contaminated ce ll culture and from soil. The isolates did not differ in their macroscopic and microscopic morphology, in their protein patterns analysed by SDS-PAGE and in their susceptibility to amphotericin B and itraconazole, The RFLP an alysis of total genomic DNA digested by EcoRI resulted in patterns that wer e too faint for interpretation. However, after hybridisation of the digeste d DNA with a short DNA probe of repetitive sequence, six different patterns were found. Based on the patterns of the randomly amplified polymorphic DN A (RAPD),vith three primers, nine different genotypes were discriminate. RA PD patterns discriminated the epidemiologically unrelated reference strains (endocarditis isolate from Thailand, soil isolate from the USA) and the is olates from Germany, It is concluded that, in contrast to the phenotypic me thods, the analysis of RAPD patterns is useful for strain differentiation o f A. terreus.