Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/1996
Publication Date: N/A
Technical Abstract: Chlamydia are intracellular bacteria that cause disease in human and animal hosts. In livestock and birds these diseases include abortion, pneumonia, arthritis, enteritis, and encephalitis. Over 60 strains of chlamydia have been identified, and some animal strains can be transmitted to humans. Chlamydia infections are difficult to correctly diagnose. To identify probes that could be used to diagnose all chlamydia infections, a 2.8 kb ribosomal DNA segment from 41 strains of chlamydia and from a chlamydia- like organism was amplified by PCR and a 1320 bp region flanked by conserved regions was DNA-sequenced in each segment. These sequences were compared using maximum parsimony analysis and also using percent distance analysis. Two functional domains within the 1320 bp region, the 16S/23S intergenic spacer (232 +/- 11 bp) and Domain I (620 +/- 2 bp) of the 23S gene, had variable regions that grouped the isolates into two lineages with hnine distinct groups. The C. trachomatis lineage contained groups specifi for humans, swine, and rodents. The non-C. trachomatis lineage contained six groups (C. pecorum, C. pneumoniae, and C. psittaci-abortion, -avian, -feline, and -guinea pig). The groupings were consistent with chlamydial host specificities, tissue specificities, and/or with the diseases they produced. Phylogenetic trees based on these data were congruent with trees previously derived from protein sequences and from DNA homology studies. DNA analysis of these genes provided a rapid and reproducible method for identifying, grouping, and classifying chlamydial strains. Conserved and group-specific ribosomal primers in the ribosomal operon will be used to develop a rapid and precise PCR-based diagnostic test for identifying and characterizing chlamydia in livestock and birds.