INCREASE IN MODERATE PENICILLIN RESISTANCE AND SEROGROUP-C IN MENINGOCOCCAL STRAINS ISOLATED IN SPAIN - IS THERE ANY RELATIONSHIP

Serogroup B Neisseria meningitidis is the main cause of meningococcal disease in Spain, but in recent years we have detected an increase in the prevalence of infection due to serogroup C meningococci. At the same time, the frequency of moderately penicillin-resistant (Pen(R)) clinical isolates, which include greater numbers of serogroup C meningococci than do penicillin-susceptible (Pen(s)) strains, has also been increasing. When we analyzed the prevalence of serogroups B and C in Pen(R) and Pen(s) meningococcal strains, we found a simultaneous increase in serogroup C strains and a decrease in serogroup B meningococci affecting both Pen(R) and Pen(s) isolates. To analyze this epidemiological change in Spain, we have applied serotyping, subtyping, and multilocus enzyme electrophoresis to serogroup C (Pen(R) and Pen(s)) strains. The two major serotypes were 2b and 2a in both groups (Pen(R) and Pen(s)), but our results suggested an association between serotype 2b and Pen(R) strains. However, multilocus enzyme electrophoresis showed that 75% of the major serotypes belonged to the same electrophoretic type. It does not appear that a new clone distinct from those already established is contributing to the increase in serogroup C meningococci in Spain.