MARSHFIELD, Wis., Oct. 3 (UPI) -- U.S. researchers say they've determined the use of antibiotics as a livestock growth stimulator increases the risk of human antibiotic resistance.
Dr. Edward Belongia of the Marshfield (Wis.) Clinic Research Foundation and colleagues examined poultry exposure as a risk factor for antibiotic resistance to Enterococcus faecium, a gut bacterium that's increasingly becoming the cause of hospital infections.
A drug combination called quinupristin-dalfopristin, also known as Synercid, is used to treat serious E. faecium infections resistant to the first-choice antibiotic. Synercid is related to virginiamycin, an antibiotic that has long been used as a growth promoter in U.S. livestock but is banned in Europe.
The scientists isolated E. faecium in stool samples from 105 newly hospitalized patients and 65 healthy vegetarians, as well as in 77 samples of conventional retail poultry and 23 antibiotic-free poultry meat samples.
Laboratory tests showed the bacteria from patients and vegetarians had no pre-existing resistance to Synercid. Resistance was rare among antibiotic-free poultry but a majority of bacterial isolates from conventional poultry samples were resistant.
The study is detailed in the Nov. 1 issue of The Journal of Infectious Diseases, and is available online.
