Fluoroquinolones are one of the most important and popular classes of antibiotics used to treat many types of infections in humans. Baytril, a fluoroquinolone recently approved for use in cattle and poultry, may be responsible for increasing human resistance to fluoroquinolones, thus reducing their ability to fight infections.

Since Baytril's approval for antibiotic treatment of infections in poultry in the United States, the U.S. National Antimicrobial Resistance Monitoring System, a national surveillance program operated by the Center for Veterinary Medicine, the Centers for Disease Control and Prevention, and the U.S. Department of Agriculture, has reported an increase in human resistance to fluoroquinolones not seen prior to Baytril's approval for use in animals. Researchers speculate that human consumption of poultry products that have been treated with the fluoroquinolone may be causing such resistance.

Bayer, Inc., the maker of Baytril, is frustrated over the safety controversy. "All of the scientific data was submitted in 1995 and we have met all the requirements requested of us in terms of that data," stated a Bayer spokesperson.

In October of 2000, the Food and Drug Administration requested a voluntary withdrawal of Baytril and a competing fluoroquinolone produced by Abbott Laboratories. Abbott withdrew its product, yet Bayer refused to remove Baytril from the market.