Organic poultry have fewer drug-resistant bacteria

In conventional poultry production in the USA, antimicrobials are used for therapeutic, prophylactic and non-therapeutic purposes. Researchers have shown that this can select for antibiotic-resistant commensal and pathogenic bacteria on poultry farms and poultry-derived products, EHP reports. However, no studies in the USA have investigated on-farm changes in resistance as conventional poultry farms transition to organic practices and cease using antibiotics.

Therefore, the objective of a recent study was to evaluate the prevalence of antibiotic-resistant Enterococcus on conventional poultry farms in the USA that transitioned to organic practices. Poultry litter, feed, and water samples were collected from ten conventional and ten newly organic poultry houses in 2008 and tested for Enterococcus. Litter, feed and water samples were Enterococcus-positive. The percentages of resistant E. faecalis and resistant E. faecium were significantly lower among isolates from newly organic versus conventional houses for two (erythromycin and tylosin) and five (ciprofloxacin, gentamicin, nitrofurantoin, penicillin and tetracycline) antimicrobials respectively. 42 % of E. faecalis isolates from conventional poultry houses were multi-drug resistant, compared to 10 % of isolates from newly organic houses, and 84 % of E. faecium isolates from conventional houses were MDR compared to 17 % of isolates from newly organic poultry houses.

Environmental Health Perspectives