Value of different methods for the characterisation of Aspergillus terreus strains

Abstract

To evaluate different methods for strain differentiation, 10 isolates of Aspergillus terreus from Germany and two epidemiologically unrelated strains were investigated. The sources of the isolates were patients with cystic fibrosis (4), immunosuppression (2), otitis externa (2), sinusitis (1) and endocarditis (1). Environmental isolates were obtained from a contaminated cell 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 analysis of total genomic DNA digested by EcoRI resulted in patterns that were too faint for interpretation. However, after hybridisation of the digested DNA with a short DNA probe of repetitive sequence, six different patterns were found. Based on the patterns of the randomly amplified polymorphic DNA (RAPD) with three primers, nine different genotypes were discriminate. RAPD patterns discriminated the epidemiologically unrelated reference strains (endocarditis isolate from Thailand, soil isolate from the USA) and the isolates from Germany. It is concluded that, in contrast to the phenotypic methods, the analysis of RAPD patterns is useful for strain differentiation of A. terreus.

Genetic variability of Aspergillus terreus from dried grapes

“…No difference was found in the macroscopic and microscopic morphology of the five different A. terreus isolates. Similar results were obtained by Rath [10]. The first report of different methods of strain differentiation for A. terreus was given by them.…”

“…Rath [10] reported nine different genotypes of A. terreus by RAPD analysis. Previously, this technique was used successfully in fingerprinting other Aspergillus [16,10] showing a high genetic diversity in A. fumigatus and A. flavus.…”

“…Previously, this technique was used successfully in fingerprinting other Aspergillus [16,10] showing a high genetic diversity in A. fumigatus and A. flavus. Similar results were also found for A. terreus in the present study (Figure 1) Therefore, RAPD seems to demonstrate diversity within a species.…”

“…RAPD-PCR typing has proven useful in many epidemiological investigations [2,10]. The polymerase chain reaction (PCR) has been adapted for fingerprinting microorganisms by using paired primers derived from previously characterized sequences for PCR amplification.…”

Differentiation of Aspergillus ustus Strains by Random Amplification of Polymorphic DNA

“…An analysis of the protein patterns of water-soluble proteins of whole-cell lysates in Coomassie blue-stained SDS-PAGE gels (7.5%) was performed as described previously (11).…”