The role of gut flora and animal passage in the colonisation of adult mice with Campylobacter jejuni.

Adult female mice were given drinking water containing tobramycin 0.05 mg/ml for a week. After a further day without antibiotic they were inoculated intragastrically with one of three strains of Campylobacter jejuni. Colonisation of the gastrointestinal tract was judged by culturing faecal pellets. Tobramycin-treated mice differed from untreated animals in that many more of them discharged infected pellets, and their pellets contained 5- greater than 300 times more campylobacters. Colonisation could be prevented by inoculating the tobramycin-treated animals intragastrically, 24 h before the administration of C. jejuni, with a bacterial suspension prepared from normal faecal pellets. Coliforms, lactobacilli, the two in combination, and anaerobes grown from faecal pellets were not effective in preventing colonisation. Most of the C. jejuni were found in the large intestine of the tobramycin-fed mice. The persistence of colonisation of six dams nursing C. jejuni-infected offspring ranged from 10 to at least 29 weeks.