Molecular characteristics of Neisseria meningitidis strains isolated in Burkina Faso in 2001.

In the course of an epidemic of meningitis in Burkina Faso in 2001, 27 cerebrospinal fluid samples from patients in 7 districts were forwarded to Norway for isolation and characterization of the causative agents. Neisseria meningitidis was isolated from 13 (48%) samples. The isolates were analysed using serological and genetic methods. Of the 13 strains, 4 were serogroup A, serotype 21:P1.9, sequence type (ST)-5 and belonged to clonal subgroup III, while the remaining 9 strains were serogroup W135, serotype 2a:P1.5,2, ST-11 and belonged to the electrophoretic type-37 complex. PCR analyses revealed meningococcal DNA in 13/14 culture-negative samples. Sequence analysis of the PCR products demonstrated that at least 3 different meningococcal strains were responsible for these 13 cases. Our results show that the W135 strain associated with the 2000 hajj (Muslim pilgrimage) outbreak was a significant cause of disease in Burkina Faso in 2001. Further studies are warranted to determine whether W135 is about to replace serogroup A in sub-Saharan Africa.