Molecular epidemiology of Campylobacter jejuni in broiler flocks using randomly amplified polymorphic DNA-PCR and 23S rRNA-PCR and role of litter in its transmission

Poultry has long been cited as a reservoir for Campylobacter spp,, and litt er has been implicated as a vehicle in their transmission. Chicks were rais ed on litter removed front a broiler house positive for Campylobacter jejun i, Litter was removed from the house on days 0, 3, and 9 after birds were r emoved for slaughter. Chicks were raised on these three litters under contr olled conditions in flocks of 25, None of these birds yielded C, jejuni in their cecal droppings through 7 weeks. Two successive flocks from the same Campylobacter-positive broiler house were monitored for Campylobacter colon ization. Campylobacter jejuni prevalence rates were determined for each flo ck. Randomly amplified polymorphic DNA (RAPD)-PCR and 23S rRNA-PCR typing m ethods were used to group isolates. A high prevalence (60%) of C. jejuni in flock 1 coincided with the presence of an RAPD profile not appearing in fl ock 2, which had a lower rate of prevalence (28%). A 23S rRNA-PCR typing me thod was used to determine if strains with different RAPD profiles and diff erent prevalence rates contained different 23S sequences. RAPD profiles det ected with higher prevalence rates contained a spacer in the 23S rRNA regio n 100% of the time, while RAPD profiles found with lower prevalence rates c ontained an intervening sequence less than 2% of the time. Data suggest var ying colonizing potentials of different RAPD profiles and a source other th an previously used litter as a means of transmission of C,jejuni, These mol ecular typing methods demonstrate their usefulness, when used together, in this epidemiologic investigation.