A new taxon in the genus Neisseria

Among 3,520 strains of Neisseria and Branhamella received in the laboratory during the last seven years, 13 could not be speciated. These 13 strains (Neisseria sp. group) were isolated from the throats of healthy children in Europe and Africa. The Neisseria sp. group oxidized glucose and maltose similarly to N. meningitidis. The observation of polysaccharide synthesis prompted the authors to examine the genomic relationship between the Neisseria sp. group and the type strains of all species of Neisseria and Branhamella. Additional phenotypic characteristics were also examined. Results indicated that the 13 strains in this study belong to the genus Neisseria, in which they constitute one homogenous hybridization group. They belong to the same genospecies as N. gonorrhoeae, N. meningitidis, N. flavescens and N. lactamica. However, they differ from N. meningitidis in production of polysaccharides, growth requirements and the lack of gamma-glutamyl transferase activity.