Klebsiella trevisanii: a New Species from Water and Soil

Abstract

We determined the taxonomic position of 17 strains of bacteria that were previously classified as “Klebsiella-like” strains, corresponding to group K of Gavini et al. [Ann. Microbiol. (Paris) 128B:45–59, 1977]. These strains were isolated from sewage, surface waters, drinking waters, and unpolluted soils. Deoxyribonucleic acid (DNA)-DNA hybridizations and a numerical analysis of electrophoretic protein patterns were used in this study. At least 82% of the group K strains investigated formed a tight protein electrophoretic cluster. The DNA homology values for all of the selected group K strains were higher than 73% and indicated the genetic homogeneity of this group. Two strains, CUETM 77–177 and CUETM 78–134, which were classified as group L strains by Gavini et al., were identified as true members of group K by the above-mentioned methods. The protein gel electrophoretic technique permitted distinction of group K strains from other species of the genus Klebsiella. DNA-DNA hybridization experiments revealed relatedness values of 40 to 71% between the reference strain of group K and the species Klebsiella mobilis, Klebsiella pneumoniae, Klebsiella oxytoca, and Klebsiella terrigena. Phenotypic characteristics, protein electrophoretic patterns, and the results of DNA-DNA hybridizations supported the individuality of group K, and we propose the name Klebsiella trevisanii sp. nov. for the strains of this group. These strains were positive in the Voges-Proskauer, urease, and β-galactosidase tests, grew at 4 and 41°, utilized histamine as a carbon source, did not ferment melezitose, and did not use m-hydroxybenzoate; indole was produced by 42% of the isolates. Strain CIP 81–36 (= CUETM 78–120) was designated the type strain of this species.