A new colonial type of N. gonorrhoeae.

A new variant of Neisseria gonorrhoeae, designated Type 1(1), is described. Colonies of the new type resemble those of Types 1 and 2 in physical characteristics but are granular with a slightly crenated edge and are a deeper gold in colour. The virulence of Type 1(1) in the chick embryo is in keeping with that of Types 1 and 2 but is significantly different from Types 3, 4, and 5. Type 1(1) could be maintained in the laboratory for 6 months, provided that daily selective subcultures were performed. In the absence of this, Type 1(1) reverted to Type 5. It was also possible to preserve the stability of Type 1(1) for long periods by immersion in liquid nitrogen. Pili have been demonstrated on the new type.