PROTEINIC AND GENOMIC IDENTIFICATION OF SPOTTED-FEVER GROUP RICKETTSIAE ISOLATED IN THE FORMER USSR

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), restriction fragment length polymorphism of polymerase chain reaction- amplified genes (RFLP-PCR), and pulsed-field gel electrophoresis (PFGE ) were used to identify 25 isolates of spotted fever group rickettsiae collected in the former USSR. Six Rickettsia akari isolates which wer e identical to the MK reference strain from the American Type Culture Collection were found. Also, 14 isolates were found to be Rickettsia s ibirica and identical to reference strain 246. Two of three isolates p reviously considered as atypical, low-pathogenic strains of R. sibiric a, were found to be strains of Rickettsia slovaca. The third, strain S , was similar in its RFLP-PCR profile to ''R. africae'' sp. nov. (prop osed name for a rickettsia pathogenic for human beings in southern Afr ica) but in its SDS-PAGE and PFGE profiles was unique among spotted fe ver group rickettsiae. Strain M-1 was confirmed as a genetic variant o f Rickettsia conorii. The Astrachan isolate, the causative agent of a tick-bite rickettsiosis at the North of the Caspian Sea, showed a prev iously described RFLP-PCR profile identical to that of the Israeli tic k typhus rickettsia, but its SDS-PAGE and PFGE profiles different from those of the other strains tested.