Pseudomonas pickettii, a New Species of Clinical Origin Related to Pseudomonas solanacearum

Abstract

Twenty strains of Pseudornonas isolated from clinical specimens were found to constitute a homogeneous group which we recognize as a species and name Pseudomonas pickettii. On the basis of deoxyribonucleic acid hybridization data, this species appears to be most closely related to the phytopathogenic species P. solanacearum. The type strain of P. pickettii is K-288 (ATCC 275 1 1). Thirty-five bacterial strains isolated from hospital specimens were received by us from M. J. Pickett, with the tentative identification of Pseudomonas pseudoalcaligenes type 2. When tested by our methods (4, 7) 19 of these strains were found to constitute a phenotypically homogeneous group which differs in over 40 characters from both P. pseudoalcaligenes and P. alcaligenes as described by us (7). Another strain, also received from M. J. Pickett as an "unclassified denitrifier," could also be assigned to this homogeneous group. We further com- pared the phenotypic properties of this group of strains with those of other well-characterized Pseudomonas species and performed a limited number of deoxyribonucleic acid (DNA)-DNA hybridization experiments to determine whether it may represent a new species.