The detection of genetic variation in Leptospira interrogans serogroup ICTEROHAMORRHAGIAE by ribosomal RNA gene restriction fragment patterns

Twenty-eight isolates of catalase-negative/weak (CNW) thermophilic campylobacters from human blood and faecal cultures were characterized by one-dimensional (1-D) high-resolution SDS-PAGE of cellular proteins. A further 11 Campylobacter strains were included for reference purposes. Partial protein patterns were used as the basis for numerical analysis, which showed that all of the hippurate-positive strains had a high similarity to C. jejuni. Two subclusters were formed within C. jejuni corresponding to C. jejuni subsp. doylei (15 strains) and C. jejuni subsp. jejuni (4 strains). Most of the paediatric strains from South Africa were members of C. jejuni subsp. doylei. Hippurate-negative CNW thermophilic strains were identified as "C. upsaliensis". The analysis demonstrated that the catalase-negative C. jejuni strains were quite distinct from "C. upsaliensis" and that electrophoretic protein patterns provide an excellent criterion for the identification of subspecies within C. jejuni.