Researchers have found there is no difference in the
presence of antibiotic-resistant bacteria between pigs raised conventionally
and those raised under antibiotic-free programs.
The North Carolina team found Campylobacter coli in both pig
farms and said it seems the antibiotic-resistant bacteria come from the
environment so it doesn’t matter whether hog farmers try to raise their pigs
without antibiotics.
This peer-reviewed research has been published on the internet at www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0044662 .
Dr. Siddhartha Thakur, assistant professor of population health and
pathobiology, had previously found that antibiotic-resistant C. coli, a leading
cause of foodborne illness in the United States, was present in both
ABF-certified and conventionally raised pigs.
The pathogen was present in both groups in all facilities from breeding
to processing.
Thakur wanted to determine whether the C. coli that he found in each
group was genetically the same, in order to see if the presence or absence of
antimicrobial usage had an effect on the pathogen’s genetic makeup.
The rise of antibiotic-resistant pathogens such as C. coli is a concern
for the food animal industry. Some pig farms have switched to raising ABF pigs
in an attempt to get away from the conditions that facilitated antibiotic
resistance.
The hope is that once the selection pressure – in the form of
antimicrobial use – on C. coli to retain antibiotic resistance decreases, the
pathogen will lose its resistance.
Over several years, Thakur and Ph.D. student Macarena Quintana-Hayashi
collected thousands of samples from pigs and their surrounding environments,
and performed a genetic analysis on 200 representative isolates of C. coli, to
see if these strains were similar.
