ARS | Publication request: Differential Protein Expression between Poor and Robust Colonizing C. jejuni Isolates

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: March 18, 2013
Publication Date: N/A

Technical Abstract: Introduction: Campylobacter jejuni is a leading cause of bacterial gastroenteritis in humans. Poultry is considered a major source of C. jejuni but colonization mechanisms in the chicken intestine remain unclear. Purpose: The purpose of this study was to determine C. jejuni colonization-associated factors at the proteome level. Methods: The proteomes of C. jejuni were quantitatively analyzed using trypsin catalyzed 16O/18O labeling in conjunction with two-dimensional liquid chromatography separation and tandem mass spectrometry (2DLC-MS/MS). Results: After oral challenge with 105 cfu/mL of C. jejuni per chick, a poor colonizing isolate (A74/O) showed a 3 log reduction in the chick ceca relative to a robust colonizer (A74/C). C. jejuni recovered from birds were determined to be the same flaA SVR genotype of flaA short variable region as the original isolates. A total of 776 proteins were identified; and 72 proteins, which accounted for (approximately 9.28% of the total proteins identified), were significantly changed (over 1.4-fold, p < 0.05) in the good colonizer. Surprisingly, only 4 of these proteins (RplL, CjaA, GlyS, and putative oxidoreductase subunit) were up-regulated, whereas the majority (68 proteins) were down-regulated. The differentially expressed proteins mainly are primarily involved in cell motility, amino acid and lipid transport, post-translational modification, protein turnover, and chaperones. In addition, the robust colonizing isolate(A74/C) attached and invaded Caco-2 cells at significantly higher numbers than the poor colonizer (A74/O). Similarly, A74/C isolate rapidly translocated through differentiated Caco-2 monolayers compared to A74/O. Significance: The present study demonstrates that the differentially expressed proteomic profiles could be useful to further investigate the mechanisms C. jejuni uses to occupy the poultry intestine.