Prevalence and patterns of antimicrobial resistant of fecal Escherichia coli isolates among pigs on eight farrow-to-finish farms and their production environments in Shandong Province, China

The main objectives of this study were to determine the prevalence and antimicrobial resistance patterns of Escherichia coli isolates in feces of pigs and their production environments on farms. A total of 560 isolates of Escherichia coli, from 112 samples obtained from weaner and finisher pigs, feed, water, and house sparrows on 8 farrow-to-finish farms, were tested for susceptibility to 16 antimicrobials. The prevalence of resistance varied widely (0.0% to 69.5%) among the antimicrobials tested. From the tested swines, 75.75% of the isolates were resistant to one or more antimicrobials. Resistance was significantly more frequent (P = 0.005, P < 0.01) in swine isolates compared to those from feed, water, and sparrows and significantly more frequent (P = 0.007, P < 0.01) in weaner pigs compared to finisher pigs. The findings indicate that resistance to a broad range of antimicrobials was prevalent among fecal E. coli isolates of swine on the study farms. Fortunately, E. coli was not isolated from the feed, water, and house sparrows.