Study of the 16S-23S ribosomal DNA internal spacer of Coxiella burnetii.

The complete 16S-23S ribosomal DNA (rDNA) internal transcribed spacer (ITS) of 22 isolates of the obligate intracellular bacterium Coxiella burnetii, the agent of Q fever, were amplified by the polymerase chain reaction (PCR) and sequenced using an automated laser fluorescent DNA sequencer. The ITS measured 497 base pairs (bp) and encoded isoleucine-tRNA and alanine-tRNA. The comparison of the sequence alignments of the 22 C. burnetii strains revealed very high levels of sequence similitary (> 99%) although they had different geographic origins and phenotypic characteristics. Sequencing of the 16S-23S rDNA ITS of C. burnetii could be utilized for identification of the bacterium but is not applicable to studies of epidemiology, virulence and taxonomy.