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 isoleucin
e-tRNA and alanine-tRNA. The comparison of the sequence alignments of
the 22 C. burnetii strains revealed very high levels of sequence simil
itary (> 99%) although they had different geographic origins and pheno
typic characteristics. Sequencing of the 16S-23S rDNA ITS of C. burnet
ii could be utilized for identification of the bacterium but is not ap
plicable to studies of epidemiology, virulence and taxonomy.