Investigation for a more virulent variant among the C : 2b : P1.2,5 Spanish meningococcal epidemic strains by molecular epidemiology

A rise in the incidence of meningococcal disease has occurred in Spain in r ecent years, especially in some regions in the north-west of the country. M ost cases have been caused by meningococci characterised as Neisseria menin gitidis C:2b:P1.2,5. A total of 107 C:2b:P1,2,5 meningococcal isolates (60 from patients and 47 from carriers) and 12 isolates showing related antigen ic combinations (C:2b:NST, C:2b:P1,2, C:2b:P1,5, C:NT:P1,2,5) was analysed by pulsed-field gel electrophoresis to determine the genetic variability of the epidemic and related strains. Endonucleases BglII and NheI were used t o cut chromosomal DNA, When BglII was used, most of the C:2b:P1,2,5 isolate s showed the same pulsotype regardless of whether they were from clinical c ases or carriers, Isolates showing the principal profile after digestion wi th endonuclease BglII were analysed,vith NheI. Four pulsotypes were identif ied, of which two were found in only one isolate each. The major profiles ( 1 and 2) showed differential distribution among clinical and carrier isolat es; pulsotype 1 was the most frequent among clinical isolates. However, the proportions of isolates showing profiles 1 and 2 were similar among carrie r isolates. This could indicate that there are two variants of the C:2b:P1. 2,5 strain with differing pathogenicity.