A Longitudinal Study onin Conventionally Reared Commercial Broiler Flocks in the United States: Prevalence and Genetic Diversity.

Abstract

Poultry meat contaminated with, a major bacterial cause of foodborne gastroenteritis worldwide, is considered the primary source of human campylobacteriosis. Thus, reduction or elimination ofin poultry production will have a significant impact on food safety and public health. Despite the significant progress made over the last decades, many puzzles remain about the epidemiology ofon poultry farms, hampering the development of an effective control strategy. This longitudinal study was conducted to determine the prevalence and genetic diversity ofin a U.S. commercial broiler production farm system. Cecal contents (15 samples/flock) and boot swabs (3 samples/flock) were collected from approximately 6-wk-old birds from 406 conventional broiler flocks reared in 53 houses on 15 farms (located within a relatively close geographic proximity and managed by the same poultry integrator) for up to eight consecutive production cycles and cultured for. Pulsed-field gel electrophoresis was used to investigate the genetic diversity of theisolates recovered from the cecal contents. The prevalence ofat the farm, house, and flock levels were found to be 93% (14/15), 79% (42/53), and 47% (192/406), respectively.prevalence varied remarkably among different farms and flocks, with some farms or houses testing consistently negative while others being positive all the time over the entire study period.isolation rate changed significantly by sample type (higher by cecal contentsboot swabs) and season/production cycle (higher in springother seasons). The majority (88%; 2364/2675) of the isolates were identified as, and almost all the rest (11%; 303/2675) were. Genotyping showed limited diversity within a flock and suggested persistence of someclones over multiple production cycles on the same farm. In conclusion, this study indicated that althoughprevalence was overall high, there were marked differences in the prevalence among the broiler flocks or farms tested. Future studies aimed at identification of potential risk factors associated with differentialstatus are warranted in order to develop effective on-farm interventions.