We investigated the role of factors within processing plants including environmental and body site sources for carriage of for food safety significant pathogens and dissemination of antimicrobial resistance factors among them. The objectives of the study were to determine the role of plant size and other risk factors on prevalence of resistant foodborne and commensal organisms, identify the clonality of major foodborne pathogens particularly Salmonella and Campylobacter recovered from small and large size processing plants in two predominant pig producing states (NC and IA) and to determine the similarities of antimicrobial resistance genes to better understand the likelihood of dissemination among the four important pathogens. In all four pathogens the proportion of positive samples from lairage was higher (30 to 52%) compared to other locations. It was also found that small plants had a higher percentage of pansusceptible isolates (27.4%) compared to the large processing plants (10.6%). All organisms were highly resistant to tetracycline, with the lowest prevalence in Salmonella at 69.4%. Multidrug resistance was common among isolates from both small and large processing plants, however, relatively higher in later ones. Further investigation showed that about half (47.3%) of resistance genes tested were found in at least two different bacterial organisms. Escherichia and Salmonella from the same animal were most commonly found to be carrying the same resistance genes.