Diversity of Pseudomonas strains isolated with King's B and Gould's S1 agar determined by repetitive extragenic palindromic polymerase chain reaction, 16S rDNA sequencing and Fourier transform infrared spectroscopy characterisation

King's B and Gould's S1 agar were compared with regard to the isolation of Pseudomonas from four environmental samples. In all samples, King's B gave the highest number of colony-forming units, and in some environments, there were more fluorescent colony-forming units on King's B as well. However, almost all types grew on Gould's S1, which enabled us to isolate a greater variety of groups than with King's B, fluorescent as well as non-fluorescent members of Pseudomonas. The Pseudomonas isolates were comparatively typed by repetitive extragenic palindromic-polymerase chain reaction and Fourier transform infrared spectroscopy, not previously used for environmental Pseudomonas. The two typing methods were similar in resolution, thus Fourier transform infrared spectroscopy proved fast and reproducible and is a good method for discrimination at subspecies level. Representative strains were identified by partial 16S rDNA sequencing. Thus, we suggest Gould's S1 agar be used for isolation of Pseudomonas because the results are reproducible, specific and give the most diverse recovery and the least work. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.