[Molecular epidemiology of Neisseria gonorrhoeae: typing with combined auxotype/serovar classification]

Auxotyping or determination of serovars of N. gonorrhoeae used separately can be for a limited differentiation of strains only. Combined auxotype/serovar (A/S)-classification was examined for its discriminatory ability on 360 gonococcal strains isolated over 9 years in the area of Heidelberg. The prototrophic, prolin requiring and (P)AH(U)-auxotype were the 3 most frequent auxotypes. 33 different serovars were identified. Protein-IB-serovars dominated by 75%. IB-3, IB-2 and IA-1/2 were the most frequent serovars. The (P)AH(U) auxotype is statistically significant associated with serovar IA-1/2, the PA(U) auxotype with serovar IB-2/16 and the prolin requiring auxotype with serovar IB-1. Combined typing resulted in 68 different A/S classes. The 3 most frequent classes were Proto/IB-3, (P)AH(U)/IA-1/2 and Proto/IB-2/16. The number of the A/S classes identified per year rose generally with the number of the isolated strains. Our data show the heterogeneity and dynamics of a gonococcal population. A/S classification permits the epidemiological differentiation of a gonococcal population in endemic, transient and microepidemic strains.