INCREASING INCIDENCE OF MENINGOCOCCAL DISEASE IN SPAIN ASSOCIATED WITH A NEW VARIANT OF SEROGROUP-C

Serogroup B has been the main cause of meningococcal disease in Spain since at least 1979, but in recent years an increase in the prevalence of infection due to serogroup C meningococci has been detected. In 19 96, for the first time, most cases of meningococcal disease were cause d by serogroup C strains. The sero/subtype of all serogroup C meningoc occi received from 1993 to June 1996 was determined, and the results s howed that C:2b:P1.2,5, the most common phenotype in 1995 and 1996 (63 % and 65%, respectively), represented only 4.8% of strains in 1993. Th e C:2b:P1.2,5 epidemic strains appear to be responsible for the high p revalence of serogroup C in Spain. One hundred fifty-one randomly sele cted serogroup C strains were analyzed by multilocus enzyme electropho resis, ribotyping, and pulsed-field gel electrophoresis. Pulsed-field gel electrophoresis provided the most accurate information: more than 80% of the C:2b:P1.2,5 and C:2b:P1.2 isolates exhibited one of two ver y closely related profiles, while most of the C:2b:NST and C:2b:P1.5 s trains had a pattern located at a genetic distance of 0.24 from those two profiles. The results show that C:2b:P1.2,5 strains represent a su bclone or a genetic variant of the previously identified Spanish epide mic clone C:2b:non-subtypable strains.