Prevalence of Potential Pathogenic and Antimicrobial Resistant in Danish Broilers

Avian pathogenic (APEC) are important bacteria in broiler production in terms of economy, welfare, and use of antibiotics. During a previous outbreak of APEC in the Nordic countries, it was suggested that the pathogenic clones of causing the outbreak originated from grandparent stock and were transmitted to the offspring, causing increased first week mortality. This study investigated whether the pathogenic potential of at the parent and broiler level differs in relation to pathogenic potential described by the level of virulence-associated genes and pattern of antimicrobial resistance. The hypothesis was that, due to higher biosecurity at the parent level, the population will show a lower level of antimicrobial resistance and carry fewer virulence-associated genes, as a result of fewer infections observed. From four parent flocks and eight broiler flocks, 715 were isolated from cloacal swabs of newly hatched chickens (Ross 308). The isolated were characterized by eight virulence-associated genes and phenotypic resistance against six antimicrobials. It was found that the prevalence of virulence-associated genes and phenotypic antimicrobial resistance varied significantly between flocks, and the virulence-associated genes and and resistance against ampicillin were significantly more prevalent in breeder flocks compared to broiler flocks.