CLONAL DISTRIBUTION OF INVASIVE NEISSERIA-MENINGITIDIS ISOLATES FROM THE NORWEGIAN COUNTY OF TELEMARK, 1987 TO 1995

Forty-two Neisseria meningitidis isolates were obtained from patients with meningococcal disease in the Norwegian county of Telemark (Januar y 1987 to March 1995), and all were compared by PCR amplicon restricti on endonuclease analysis (PCR-AREA) of the dhps gene, chromosomal DNA fingerprinting, and serological analysis. PCR-AREA divided the isolate s into 11 classes, of which 4, comprising 15, 8, 6, and 2 isolates, we re clonal while the remaining 8 classes were genetically heterogeneous or contained only 1 isolate. Three of the four clonal classes could b e tentatively equated with recognized epidemic clones (ET5, ET37, and cluster A4) on the basis of their phenotypic characteristics, while th e remaining clone appears to be new. There were significant difference s in the geographical distribution of clones, with class 1 (ET5-like) isolates significantly overrepresented in rural parts of Telemark, Cla ss 1 (ETS-like) isolates occurred throughout the study period and were dominant in 1987, Class 2 (ET37-like) isolates occurred from 1988 to 1992, and class 3 isolates (with no recognizable ET affinities) were f ound only in 1991 and 1992.