Antibiotic used on cows could pose health concerns for humans, Reuters investigation finds

An antibiotic widely used—and misused—on cows poses a greater threat to human health than previously thought, Michael Erman and Brian Grow report for Reuters. The U.S. Food and Drug Administration cautioned in 2012 that ceftiofur—the key component in the top-selling drug line of manufacturer Zoetis—could pose a "high public health risk, in part because the drug belongs to a class of antibiotics considered critically important in human medicine. The concern is that ceftiofur in animals could spawn antibiotic-resistant bacteria, superbugs that can infect people and defeat conventional medical treatment, even when the drug is used as directed."

"Since last year, records kept by the U.S. Department of Agriculture show that traces of ceftiofur were found at illegal levels in slaughtered animals more frequently than with any other drug," Erman and Grow write. "In 2013, ceftiofur alone accounted for one-fourth of all residue violations logged by the USDA, the data show."

"The ceftiofur residues are not themselves considered dangerous to people if ingested because the government sets its standards well below hazardous levels," Erman and Grow write. "But the traces serve as a warning sign that the drug was used shortly before the animal was killed, thus increasing the chances that the meat contains superbugs, said Guy Loneragan, a veterinary epidemiologist at Texas Tech University. Studies show that ceftiofur, more than most other drugs, can sharply increase the amount of antibiotic-resistant bacteria in an animal."

Loneragan told Reuters that it eliminates weaker bugs and leaves the stronger ones to survive and multiply. But officials at Zoetis counter that ceftiofur is safe to use as directed.

"The stakes are especially high because the drug is part of a crucial class of antibiotics called cephalosporins," Erman and Grow write. "The class includes ceftriaxone, a drug that’s vital to treating pneumonia, meningitis and salmonella infections in children, according to the FDA. The use of one type of cephalosporin can compromise the effectiveness of others in the same class." 

Paul Fey, a professor of microbiology at University of Nebraska Medical Center, told Reuters, “There is a very clear link between ceftiofur use and ceftriaxone resistance. We know that ceftiofur-resistant salmonella are clearly ceftriaxone-resistant.” (Read more)