Comparative study of colonizing and noncolonizing Campylobacter jejuni

Campylobacter jejuni A74/O and A74/C are congenic strains. An oral dose of 10(5) organisms of strain A74/C colonizes chicken intestines. Strain A74/O, from which A74/C is derived, does not colonize the chicken intestines with an oral dose of 10(5) organisms. In this study, the congenic bacteria were compared to identify possible colonization mechanisms. Differences were not observed in plasmid content or by HindIII, Pst I, Acc I, HincII, Ava I, Ava II, Xba I, and BamHI restriction enzyme digestion of total DNA. Transmission electron microscopy of negatively stained samples revealed no differences between the strains. Sections of cecal tissue from nonfed day-of-hatch chicks were cultured with each strain for 2 hours and then examined by light and electron microscopy. Both strains caused necrosis of villus epithelial cells. Immunofluorescent or silver staining revealed strain A74/C located deep in numerous epithelial crypts, but strain A74/O only was present in one sample mixed with sloughed necrotic cells. Similarly, organisms were detected by transmission electron microscopy deep in crypts in tissues cultured with A74/C, but not A74/O. Cells of A74/C detected in crypts did not appear to associate with epithelial cells. The strains did not differ in chemotactic behavior to mucin or fucose.