A recent conference, "Minimizing Antibiotic Resistance Transmission Through the Food Chain," revealed widespread concern among academics and USDA that antibiotic resistance remains a problem.
"The rapid emergence of antibiotic-resistant pathogens has major public-health and social impact," said Hua Wang, a food scientist at The Ohio State University.
The conference was jointly sponsored by USDA's Cooperative State Research, Education and Extension Service, Ohio State University Extension, and Ohio Agriculture Research and Development Center. Leading the conference, in addition to Wang, were John Sofos, center for meat safety and quality, Colorado State University, and Thaddeus Stanton of USDA's Agricultural Research Service.
Conference speakers noted that bacteria and other microorganisms causing infections are remarkably resilient and can develop ways to survive drugs meant to weaken them. This antibiotic resistance is due largely to the increasing use of antibiotics, although several speakers noted the problem is complex and cannot be tied simply to that fact. Speakers pointed out that food-producing animals are given antibiotic drugs for important therapeutic, disease prevention or production reasons. However, these drugs can cause microbes to become resistant to medications used to treat human illnesses, ultimately making some human sicknesses more difficult to treat.
Does this mean antibiotic use in agriculture should be curtailed? That was the question that keynote speaker Abigail Salyers, from the University of Illinois' microbiology department, addressed. She told attendees that even though antibiotics are usually used at very low concentrations in agriculture, they can still select for antibiotic-resistant bacteria.
"The resistant bacteria then enter the food supply. A potential hazard of consuming such food is that resistant bacterial pathogens such as Salmonella typhimurium can cause disease," she said. "Another potential hazard seldom considered but probably more serious is the transfer of resistance genes from bacteria passing through the human intestinal tract to bacteria normally occupying that site. Such bacteria are common causes of post-surgical infections." There's not yet enough data for scientists to quantify the risks associated with such scenarios, she added.
In speaking about antibiotic resistance associated with food, Sofos pointed out that antimicrobials find numerous beneficial applications in human, animal and plant health, as well as in food production. Their selective pressure, however, may lead to the emergence of resistant pathogen strains.
"Therefore, it is important to maintain the ability of pathogens to be affected by antimicrobials," he said. "The best approach to minimizing antibiotic resistance negative impact is through risk assessments." He cited major recommendations for control such as disease prevention; using antibiotics of lesser importance to human medicine; and treatment with alternative methods, including vaccines."
He also noted that, "research should also focus on the potential of antibiotics to enter animal production environments through waste streams."