October 12, 2006


Study finds antibiotic use in poultry leads to human antibiotic resistance


Antibiotic used as a livestock growth promoter increases the risk of human antibiotic resistance, a three-year study by researchers from the Marshfield Clinic Research Foundation found.


Results of the US$1.4 million study, funded by the Centers for Disease Control and Prevention in Georgia, are published in the November 1 issue of The Journal of Infectious Diseases.


Edward Belongia, M.D., Marshfield Clinic Research Foundation and his colleagues examined antibiotic resistance in Enterococcus faecium, a gut bacterium, when it is exposed to bacteria from poultry fed with antibiotics.


The investigation team based their research on virginiamycin, a growth-promoting antibiotic, used in poultry.


Virginiamycin is closely related to quinupristin-dalfopristin (Synercid), an antibiotic to treat patients with serious, antibiotic-resistant infections.


Although there is little research data on the impact of antibiotic use in livestock and its relationship to antibiotic resistance in humans, there has long been indirect evidence suggesting that antibiotic use could threathen human health, Belongia said. 


The study is one of the first to link human carriage of antibiotic resistance genes and eating poultry, offering evidence that antibiotic resistant genes can be transferred to human gut bacteria through the food supply.


The study also indicated that use of growth promoters in animals may have long-term consequences for human health, Belongia said.


The study comes on the heels of a recent FDA Veterinary Medicine Advisory Committee recommendation against an application to license a broad spectrum antibiotic, cefquinome, for use in cattle.


Belongia had spoken against the use of the drug at that hearing, saying that there was great deal of concern that this antibiotic could promote resistance to cephalosporin drugs used on patients with serious or life-threatening infections.


Belongia said although such drugs are needed to treat animals, it should not be used for promoting growth.