Genotypic and phenotypic markers in the differentiation of Neisseria gonorrhoeae strains.

Restriction enzyme (RE) patterns, using Hind III enzyme, were analysed on 101 urogenital strains of Neisseria gonorrhoeae. The strains were also analysed serologically, using monoclonal antibodies, and tested for nutritional requirements by auxotyping. In addition, testing susceptibility to doxycycline was performed by an agar-dilution method. The strains were distributed into 23 RE patterns, of which the five most common accounted for 67.3% of all isolates. The same strains were distributed into 17 serovars, of which the four most common accounted for 77.3% of all isolates. Eleven auxotypes were demonstrated, of which the four most common accounted for 85.1% of all isolates. When the methods were combined, 38 combinations of RE patterns and serovars, 25 combinations of RE patterns and auxotypes, and 31 combinations of serovars and auxotypes were seen. Combining all three methods, 40 combinations of RE patterns, serovars and auxotypes were found. Correlations were particularly seen between RE patterns and auxotypes. The strains were moderately sensitive to doxycycline, those with serological markers for WII/WIII being less sensitive than those with markers for WI.