Genotypic identification of seven Rickettsia conorii strains.

Restriction endonuclease fragment length polymorphism (RFLP) analysis and polymerase chain reaction (PCR) were used to characterize the genotypic diversity of 7 strains of Rickettsia conorii from South Africa, Ethiopia, Morocco, India and Russia. The strains of R. conorii were divided into four genotypes by Rsa I or Pst I endonuclease digestion of PCR-amplified rickettsial DNA using primers derived from the R. rickettsii 190 K antigen gene. M-1 and Barbash strains were genotypically identical, but different from Indian, Ethiopian and S7 strains, which formed another group. Simko and Moroccan strains were genotypically different from each other and also from other strains of R. conorii. We conclude that there exist a genotypic diversity among intraspecies of R. conorii.