An examination of Campylobacter fetus subsp. fetus by restriction endonuclease analysis and serology

Restriction endonuclease analysis was used to examine 70 different strains of Campylobacter fetus subsp. fetus, which were isolated from aborted sheep foetuses. The strains could be divided into seven types based on the DNA fragment patterns obtained by electrophoresis after digestion with the enzyme BstEII. With one exception, digestion with the enzyme XhoI allowed the strains to be grouped identically to that for BstEII. Antisera were made against formalized whole cells representative of each of the seven different restriction types. Analysis of these sera by tube agglutination tests using whole cells revealed five different serogroups. Examination of the 70 strains with absorbed antisera demonstrated a complex relationship between the restriction type and the external antigens of C. fetus subsp. fetus.