Benefits of poultry antibiotics may outweigh risks
antibiotics in chicken may outweigh the potential risks, according
to a risk-benefit analysis carried out by scientists in the US,
writes Anthony Fletcher.
A team of researchers led by Randall Singer of the University of Minnesota College of Veterinary Medicine found indications that antibiotic use in animal production results in healthier animals, and the meat derived from these healthier animals has lower levels of bacteria that can cause food-borne illness in people.
Singer presented the results of the study at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC) in Washington, DC, US yesterday. The presentation was one of many on antibiotic resistance, bioterrorism, and infectious disease, all of which are becoming pressing issues in food production.
Antibiotics are often used in poultry production to promote growth and to prevent them from catching diseases. The global market for biological disease control and productivity enhancement products in poultry and pigs is already valued at over US$3 billion per annum, and is likely to continue to grow.
However, Singer's studies also acknowledged that some evidence indicates that the use of antibiotics also has the potential to increase the level of antibiotic-resistant bacteria in meat.
The problem is that low doses don't kill all bacteria, allowing the most resistant bacteria to grow and potentially develop into superbugs.
According to a recent American Academy of Microbiology report, The Role of Antibiotics in Agriculture, intensive and extensive antibiotic use leads to the establishment of a pool of antibiotic resistance genes in the environment.
The AAM report claims that both pathogenic bacteria and organisms that do not cause disease may become resistant to antibiotics, and bacteria of human and animal origin can serve as reservoirs for resistance genes.
The University of Minnesota researchers therefore decided to develop a mathematical model to evaluate the potential human health risks and benefits of the use of the antibiotic, tylosin, in chickens. They compared the potential risks associated with increased levels of antibiotic-resistant bacteria in meat with the potential benefits associated with decreased risk of food-borne illness.
"Antibiotic resistance is a problem in both human medicine and animal production agriculture," said Singer.
"But our model demonstrated that the reduced number of infections and illness days associated with the use of tylosin in chicken far exceeded the increased human health risks associated with antibiotic resistance due to tylosin use."
The issue of antibiotics entering the food chain is especially pertinent in the UK, where traces of a nitrofuran, a banned veterinary medicine, were discovered in organic chicken last month. Up to 23 tonnes of the affected chicken had been distributed across the UK.
Under EU law it is illegal to use nitrofurans in food producing animals. Some studies have shown that it could increase people's risk of getting cancer.
Nitrofurans are synthetic broad-spectrum antibiotics often used for their antibacterial properties in food-producing animals. The European Union banned the use of nitrofurans in food animal production in 1995 with the United States following suit in 2002.
"Veterinarians have a commitment to both animal and human health - which are strongly connected," said Jeff Klausner, dean of the College of Veterinary Medicine at the University of Minnesota.
