The primers were developed on the basis of the rompB gene sequences of R.
SFG and typhus group (TG) rickettsia rompB gene in human sera were detected with multiplex nested PCR.
GenBank accession numbers of the rompB gene sequences used for sequence comparisons are AB003681 for R.
Nested PCR assay, with primer pairs rompB OF and rompB OR in primary reactions and rompB SFG IK rompB SFG/TG IR, and rompB TG IF in multiplex-nested reactions, was performed to identify the unknown rickettsial agents in the seropositive serum specimens and to differentiate between SFG and TG rickettsiae in terms of size.
To identify the SFG and TG rickettsiae detected in human serum specimens, nucleotide sequences of the PCR-amplified products were determined and compared with partial rompB gene sequences of various rickettsial agents obtained from the GenBank database.
The results of the multiplex nested PCR of the rompB gene were confirmed by a second PCR assay with specific primer pairs RpCS.877p and RPCS.1,258 in primary reactions and RpCS.896p and RpCS.1,233 in nested reactions.