GENOTYPIC AND PHENOTYPIC DIVERSITY OF PSEUDOMONAS-STUTZERI

A total of 49 strains of Pseudomonas stutzeri including reference strains from culture collections were phenotypically and genotypically studied. They were isolated from clinical sources, marine sediments, waste-water treatment plants and soil. DNA-DNA hybridization using the thermal melting point of the hybrids as parameter established seven genomic groups, four of them containing less than three strains. The G+C content ranged from 60.9-64,9 mol%. Phenotypical investigation using 102 characters demonstrated a considerable heterogeneity within the genomic groups. Because of the lack of useful differential tests there is still no sound basis for division of P. stutzeri at the species level. It is proposed that the term 'genomovar' be used to denote genomic groups of a nomenspecies.