NEISSERIA-WEAVERI SP-NOV (FORMERLY CDC GROUP M-5), FROM DOG-BITE WOUNDS OF HUMANS

The taxonomic relationships of strains belonging to Centers for Disease Control group M-5 were examined. Previous studies of rRNA cistron similarities placed this organism on the Neisseriaceae rRNA branch of rRNA superfamily III; the closest neighbors included the genus Neisseria and groups EF-4a and EF-4b. The group M-5 strains were characterized by a range of phenotypic tests, and their G+C contents and DNA-DNA relatedness levels were determined. In addition, a numerical taxonomic analysis of the whole-cell protein patterns (obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis) of group M-5 and related taxa was performed. The strains studied included 45 group M-5 strains, the type strains of six Neisseria species or subspecies, three group EF-4a reference strains, and three group EF-4b reference strains plus the type strain of the phenotypically similar organism Oligella urethralis. Our results showed that the group M-5 strains were members of a homogeneous taxon distinct from phylogenetically closely related taxa. The genomic divergence as revealed by levels of rRNA cistron similarity and phenotypic characteristics indicate that group M-5 can be considered a new species of the genus Neisseria. We therefore propose the new species Neisseria weaveri, with NCTC 12742 (= CCUG 4007 = ISL775/91 = LMG 5135) as the type strain. N. weaveri strains are strictly aerobic, gram-negative, nonmotile, rod-shaped organisms which are catalase and oxidase positive, nonsaccharolytic, and able to grow on MacConkey agar and do not reduce nitrate but generally reduce nitrite. The guanine-plus-cytosine contents of the DNAs of six representative strains were in the range from 50 to 51 mol%. Almost all 45 group M-5 strains were originally isolated from human wounds following dog bites.