Occurrence and genotypes of Campylobacter in broiler flocks, other farm animals, and the environment during several rearing periods on selected poultry farms.

On 15 poultry farms, broiler flocks, other farm animals, and the environment were examined for Campylobacter. Flocks were examined weekly for six or three rearing periods. Of the 5’154 collected samples, 311 (6%) from 14 farms were Campylobacter positive. Positive samples originated from broiler flocks, the broiler houses, cattle, pigs, bantams, a horse, a laying hen flock, and a mouse. Amongst them, 288 tested positive for C. jejuni and 92 for C. coli. The analysis of 917 isolates by flagellin gene typing and pulsed-field gel electrophoresis, and of 15 assorted strains by amplified fragment length polymorphism allowed the following conclusions: (i) on eight farms (A, D, H, K, L, M, O, P) identical genotypes were isolated from broilers and other farm animals emphasizing their importance as reservoirs and risk factors for flock colonization and retrieving the role of personnel moving between areas as potential vectors; (ii) on four farms (C, D, I, L), indications of persistent contamination of the broiler house were evident and thereby the importance of efficient cleaning and disinfection was underlined; (iii) the previously described sources for broiler flock colonization could be excluded for certain genotypes from eight farms suggesting the existence of more potential vectors or niches; (iv) especially on farms with extensive outdoor flocks, multiple genotypes were found within a rearing period; and (v) some genotypes were identical across farms. The significance of such strains remains to be elucidated