ARS | Publication request: Molecular Phylogeny of the flaA Short Variable Region and invasiveness among Campylobacter spp. isolated from the blood and ceca of commercial broilers

Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: March 26, 2008
Publication Date: July 20, 2008
Citation: Richardson, L.J., Cox Jr, N.A., Buhr, R.J., Akins, E.D., Hiett, K.L., Harrison, M.A. 2008. Molecular Phylogeny of the flaA Short Variable Region and invasiveness among Campylobacter spp. isolated from the blood and ceca of commercial broilers. Poultry Science Association Meeting Abstract. 87(S1):102.

Technical Abstract: Campylobacter spp. have been recovered from several internal tissues of broilers and broiler breeders including aseptic recovery from the circulating blood of commercial broilers. The objectives of this study were to evaluate the genetic relatedness of the Campylobacter isolates obtained from the circulating blood and ceca of broilers and the invasiveness of those isolates. Genotyping of the isolates was performed utilizing the flagellinA Short Variable Region (flaA-SVR) DNA sequence analysis. Invasiveness of 22 blood isolates into Caco-2 cells was evaluated utilizing a gentamicin resistant assay. In addition the isolates from the ceca of broilers where the blood isolates were most invasive were also evaluated. Isolates recovered from the blood and ceca from 9 flocks contained 7 different subtypes. The predominant subtype (flaA-SVR type 1) contained isolates recovered from three flocks and from all three integrators. Different subtypes were recovered from the blood and ceca of only five broilers across three flocks. Closely related subtypes of Campylobacter spp. were naturally present among flocks and integrators. The Campylobacter isolates that adhered to the polarized Caco-2 cells ranged from 0.001-3.22% of the starting inoculums. The invasiveness of the Campylobacter isolates into polarized Caco-2 cells ranged from 0.000-1.255%. From the invasion assays, 2 blood isolates were found to be highly invasive, 1 showed medium invasiveness, 6 marginal invasiveness, and 13 no invasiveness into Caco-2 cells. The ceca isolates from the 2 highly invasive blood isolates were not found to be invasive. An isolate that was recovered from the blood of one bird was found to be highly invasive but the isolate recovered from the ceca was non-invasive even though the isolates were similar by flaA-SVR DNA sequence analysis. Further investigations into the similarities and differences among the subtypes and invasiveness isolates obtained from the blood and ceca are needed to enable elucidation of the mechanisms by which these isolates enter into circulating blood of commercial broilers.