| Summary: | <p>Abstract</p> <p>Background</p> <p><it>Campylobacter fetus </it>subspecies <it>venerealis </it>is the causative agent of bovine genital campylobacteriosis, asymptomatic in bulls the disease is spread to female cattle causing extensive reproductive loss. The microbiological and molecular differentiation of <it>C. fetus </it>subsp. <it>venerealis </it>from <it>C. fetus </it>subsp. <it>fetus </it>is extremely difficult. This study describes the analysis of the available <it>C. fetus </it>subsp. <it>venerealis </it>AZUL-94 strain genome (~75–80%) to identify elements exclusively found in <it>C. fetus </it>subsp. <it>venerealis </it>strains as potential diagnostic targets and the characterisation of subspecies virulence genes.</p> <p>Results</p> <p>Eighty Kb of genomic sequence (22 contigs) was identified as unique to <it>C. fetus </it>subsp. <it>venerealis </it>AZUL-94 and consisted of type IV secretory pathway components, putative plasmid genes and hypothetical proteins. Of the 9 PCR assays developed to target <it>C. fetus </it>subsp. <it>venerealis </it>type IV secretion system genes, 4 of these were specific for <it>C. fetus </it>subsp. <it>venerealis </it>biovar <it>venerealis </it>and did not detect <it>C. fetus </it>subsp. <it>venerealis </it>biovar <it>intermedius</it>. Two assays were specific for <it>C. fetus </it>subsp. <it>venerealis </it>AZUL-94 strain, with a further single assay specific for the AZUL-94 strain and <it>C. fetus </it>subsp. <it>venerealis </it>biovar <it>intermedius </it>(and not the remaining <it>C. fetus </it>subsp. <it>venerealis </it>biovar <it>venerealis </it>strains tested). <it>C. fetus </it>subsp. <it>fetus </it>and <it>C. fetus </it>subsp. <it>venerealis </it>were found to share most common <it>Campylobacter </it>virulence factors such as SAP, chemotaxis, flagellar biosynthesis, 2-component systems and cytolethal distending toxin subunits (A, B, C). We did not however, identify in <it>C. fetus </it>the full complement of bacterial adherence candidates commonly found in other <it>Campylobacter </it>spp.</p> <p>Conclusion</p> <p>The comparison of the available <it>C. fetus </it>subsp. <it>venerealis </it>genome sequence with the <it>C. fetus </it>subsp. <it>fetus </it>genome identified 80 kb of unique <it>C. fetus </it>subsp. <it>venerealis </it>AZUL94 sequence, with subsequent PCR confirmation demonstrating inconsistent amplification of these targets in all other <it>C. fetus </it>subsp. <it>venerealis </it>strains and biovars tested. The assays developed here highlight the complexity of targeting strain specific virulence genes for field studies for the molecular identification and epidemiology of <it>C. fetus</it>.</p>
|
|---|