American beekeepers will soon have a new antibiotic with which to protect their colonies from American foulbrood disease, thanks to Agricultural Research Service (ARS) studies that paved the way for the compound's regulatory approval.

Tylan Soluble (tylosin tartrate), produced by Elanco Animal Health of Greenfield, Ind., was approved for use Oct. 20 by the U.S. Food and Drug Administration, following the agency's review of research data compiled by scientists with the ARS Bee Research Laboratory in Beltsville, Md.

American foulbrood is among the most widespread and devastating diseases of honeybees. Caused by the bacterium Paenibacillus larvae, the disease kills young bee larvae and transforms their remains into dark, shriveled ropes or "scales." These contain billions of spores that are easily spread by nurse bees. Although American foulbrood poses no human danger, severe outbreaks can weaken or kill entire bee colonies, according to Mark Feldlaufer, who leads the ARS Beltsville bee lab.

Before tylosin tartrate, only one other antibiotic, oxytetracycline hydrochloride (Terramycin), was available for use against American foulbrood. However, reliance on this one compound has prompted the emergence of resistant strains of American foulbrood.

Tylosin tartrate is already approved for therapeutic use in chickens and swine, and as a feed-efficiency aid in turkeys. Its approval for honeybees marks a first for a so-called minor animal species. Feldlaufer's team made this approval possible by furnishing the FDA with a wealth of information on tylosin tartrate's field efficacy and safety, both for honeybees and humans. For example, the team determined the necessary dosage, application methods and timing of treatment in honeybee hives.

Although the drug approval labels honey bees as a "minor animal species," the bee's importance to U.S. agriculture is hardly minor. By one estimate, honey bee pollination of apples, almonds, blueberries and many other agricultural crops results in yield and quality improvements valued at more than $14 billion annually.