[Molecular epidemiology of meningococcal meningitis in Mali: isolation of a new class 1 protein variant (P1.y)].

The study deals with 570 strains of Neisseriaceae isolated between 1989 and 1994 in Mali: 396 of the strains were isolated from samples of cerebrospinal fluid and 174 from the throat. Serogroup C accounted for 55% of all strains. Antigenic structure was determined by ELISA, SDS-PAGE and transfer to nitrocellulose membrane for immunoblotting with monoclonal antibodies produced at the Max Planck Institute for Molecular Genetics. For serogroup A, the class 1 protein types found were P1.7 for strains isolated prior to 1994 and P1.9 for strains isolated in 1994. P1.7 is specific to clone IV-1 and P1.9 to clone III-1, which was responsible for the 1994 epidemic. All strains of serogroup C isolated from fluid CSF and most strains isolated from the throat exhibit a new type of class 1 protein which the authors have designated P1.y. P1.y is characteristic of Malian strains of serogroup C; it is rare or absent in strains from other countries (Burkina Faso, Ghana, Italy, USA). The nucleotide sequence of the gene expressing P1.y and the corresponding amino acid sequence were determined at the National Institute for Biological Standards and Control, England.