GENOTYPIC DIVERSITY AMONG CAMPYLOBACTER-JEJUNI ISOLATES IN A COMMERCIAL BROILER FLOCK

Analysis of nucleic acid polymorphism in the flagellin genes of Campyl obacter jejuni was used to investigate genetic diversity among Campylo bacter spp, in a commercial broiler flock, Three hundred single coloni es of C. jejuni were isolated from fecal samples collected meekly for 3 weeks immediately before slaughter, Both the flaA and flaB gents mer e amplified by PCR, and the PCR product was digested with the restrict ion enzyme AluI. The fragments generated were then analyzed by agarose gel electrophoresis. Among the 300 recovered isolates, five different restriction fragment length polymorphism profiles mere observed. Thre e of these profiles mere dominant during the course of the study, and the other two profiles were detected at low frequency. Analysis of gen etic variation in C. jejuni over the course of an experimental infecti on lasting 7 weeks indicated that there was no obvious drift in the fl agellin gene type. These findings demonstrate that a range of bacteria l genotypes can constitute the bacterial population within a commercia l poultry flock, with the most likely sources of these types being mul tiple environmental exposure and/or genetic drift within the populatio n, This degree of diversity must be considered in epidemiological anal yses which utilize genetic typing methods that investigate Campy-lobac ter contamination of any food source, including poultry, to ensure tha t the total gene pool for C. jejuni is evaluated.