North Carolina State University researchers have found identical strains of antibiotic-resistant Campylobacter Coli in both “antibiotic-free” and conventionally raised pigs. The finding may indicate that these antibiotic-resistant pathogens can persist and thrive in the environment, regardless of antimicrobial usage by pork producers.

Siddhartha Thakur, North Carolina State assistant professor, had previously found that antibiotic-resistant C. coli, a leading cause of foodborne illness in the United States, was present in both antibiotic-free-certified and conventionally raised pigs in all facilities from breeding to processing. The researcher wanted to determine if the presence or absence of antimicrobial usage had an effect on the pathogen’s genetic makeup.

Over several years, Thakur found that the Campylobacter populations in both conventional and antibiotic-free swine production systems were the same. Since the different pig populations never came into contact with each other, the researcher concluded that the environment must be playing a large role in the continuing survival of antibiotic-resistant C. coli than previously thought.

For the antibiotic-free pigs, the environment is then playing an important role in their exposure to these resistant strains. Thakur concludes that if the environment itself, and not the pig, is serving as a reservoir for C. coli, then we will most probably continue to find resistant bacterial populations, regardless of a producer’s on-farm antimicrobial use.

The report is available at