Septicaemia due to Neisseria lactamica—Initial confusion with Neisseria meningitidis

Neisseria lactamica, isolated from a baby with septicaemia, was at first thought to be Neissera meningitidis, possibly acquired in hospital. Extensive investigation of contacts was made until the O-nitrophenyl-D-galactopyranoside reaction proved positive. Distinction between the two species, easily made in this way, is important both in individual patients and in population surveys.