Key findings from a risk assessment of two macrolide antibiotic compounds, tylosin and tilmicosin, have determined that their use in US food animal production is safe to public health.
The results of the assessment, which was conducted by leading food safety, public health and veterinary experts, were presented at the recent Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Chicago.
"Our risk assessment scientifically addresses questions regarding the potential impact macrolides may have on human health, and shows that current uses of tylosin and tilmicosin in food animals are safe," said lead author H. Scott Hurd, Ph.D., Hurd-Health Consulting. "The use of these macrolide antibiotics in livestock and poultry in the US is important for producing safe and healthy foods."
According to the risk assessment results, the probability of someone in the US experiencing treatment failure due to the acquisition of resistant food-borne bacteria from eating meat or poultry from animals that have been provided or treated with either tylosin or tilmicosin is very low: less than one case in 10 million for resistant Campylobacter and less than one case in 3 billion per year for resistant Enterococcus faecium.
"While antibiotic resistance in humans is growing in the United States, the major factor affecting resistance development is human antibiotic use, not food animal use," said Ronald Jones of The JONES Group/JMI Labs. "Surveillance data from the SENTRY Antimicrobial Surveillance Program and other monitoring programs clearly show a disconnect between antibiotic resistance patterns in humans and animals. Government authorities should continue to review global resistance patterns and use scientific methods, such as risk assessment, to make decisions."
Tylosin and tilmicosin are used in feedlot cattle to treat respiratory diseases and to prevent liver abscesses. They are used in poultry and swine to treat, prevent, and control disease, as well as for improved feed efficiency and weight gain. The experts reviewed the uses of these antibiotics in food animal production in the US, analysed the potential risk for a person to either acquire macrolide-resistant Campylobacter, a food-borne bacterium, or macrolide-resistant E. faecium, which is thought to carry antibiotic resistance genes. Then, they determined the potential for ineffective human macrolide antibiotic treatment as a result.
"Tylosin and tilmicosin are beneficial in keeping animals healthy and provide us with a safer food supply as a result," said Stephanie Doores, Ph.D., a food safety expert at Pennsylvania State University in University Park, PA. "People would be more likely to die from a bee sting than for their antibiotic treatment to fail because of macrolide-resistant bacteria in meat or poultry."
Low risks associated with the use of tylosin and tilmicosin are evident across beef, poultry and pork.
The report's findings will be keenly observed in Europe, where control of antibiotics for animal food production is generally regarded as being tighter. A recent ruling by the European Commission deemed that no antibiotics could be used for animal production as a means of growth promotion. The use of antibiotics to control disease and infection in animals has been declining on a global basis in recent years following increasing awareness of the effects of eating treated meat on the human immune system.