Gonococcal W serogroups in Scandinavia. A study with polyclonal and monoclonal antibodies.

A total of 849 gonococcal strains from 659 patients in Copenhagen (Denmark), Helsinki (Finland), Oslo and Trondheim (Norway) and Stockholm (Sweden) were included in the study. Using coagglutination reagents with polyclonal and monoclonal antibodies the strains were serogrouped into the previously described gonococcal serogroups W I, W II and W III. W II strains were dominating in all five towns (60.0%-70.9% of the strains), but W III strains were rarely isolated. W I strains were more frequent among women than among men. With the monoclonal reagents, W I, W II and W III strains could be further subdivided into 12, 29 and two different serovariants (serovars), respectively. One of the W I serovars was dominating (76%-94% of W I strains) in all five towns, and apart from this serovar, only three to five other W I serovars were seen in each town. Of W II strains, on the other hand, a greater variety of serovars were seen: between six in Trondheim and 17 in Oslo, and no one was dominating as among W I strains. Different W II serovar patterns were found in the different towns. Even between the two participating laboratories in each of the towns, Oslo and Helsinki, differences were noted. The epidemiological value of this is discussed. Ten of the 11 beta-lactamase-producing gonococcal strains isolated belonged to unusual serovars. None of the monoclonal coagglutination patterns corresponded to a single polyclonal pattern. There were, however, some relations between the two systems. In earlier studies it was shown that in smaller Swedish towns W I strains dominated. A hyphothesis about protective anti-Protein I antibodies is discussed to explain the differences in distribution of W I and W II strains between smaller and larger towns and between women and men.