Preservation of Neisseria gonorrhoeae by the gelatin-disc method

SUMMARY Studies of Neisseria gonorrhoeae are difficult to perform because of the organism's poor survival in vitro. To solve this problem we tried to preserve the organism by a gelatin-disc method. The rate of survival and changes of variations in some biochemical properties of eight strains of N. gonorrhoeae were followed for three years. These studies proved that preservation was satisfactory with only a 1/10 reduction of the living cells. Another trial showed that the organism survived for over six months after being frozen at-200C. The colonial types, agglutina-tion against red cells from rabbit and guinea pig, and antibiotic susceptibility to penicillin, chloram-phenicol, tetracycline, kanamycin, and streptomycin did not change after three years ' preservation. Introduction Material and methods Kellogg et al. (1963, 1968) demonstrated a close correlation between colonial type and pathogenicity of Neisseria gonorrhoeae. Later Swanson et al. (1971) detected pili in pathogenic Ti and T2 colonies