Sep 16, 2011 (CIDRAP News) – The US government needs to collect much more data on antibiotic use in food animals and resistant bacteria in animals and retail meat to clarify the possible links between them, the Government Accountability Office (GAO) said in a report released this week.
Government agencies have collected some data, but the data "lack crucial details necessary to examine trends and understand the relationship between use and resistance," the GAO said. The agency also said a shortage of data makes it unclear whether a voluntary strategy the government uses to deal with concerns about older antibiotics is working.
A number of medical, public health, and food safety groups for years have been advocating restrictions on the use of antibiotics in food animals, because of concern that excessive use gives rise to resistant bacteria, which can then spread to humans via food.
As noted in the report, however, the Food and Drug Administration (FDA) has banned just one antibiotic for use in food animals out of concern about encouraging bacterial resistance. In 2000 the FDA proposed to ban the use of two fluoroquinolones, enrofloxacin and sarafloxacin, in poultry. The maker of sarafloxacin voluntarily withdrew the product, but the enrofloxacin manufacturer opposed the move, and it took the FDA until 2005 to finally ban its use in poultry.
The new GAO report repeats the main thrust of a report issued in 2004, in which the agency called for improved data collection and risk assessment.
"Since GAO's 2004 report, FDA began collecting data from drug companies on antibiotics sold for use in food animals, but the data do not show what species antibiotics are used in or the purpose of their use, such as for treating disease or improving animals' growth rates," the new report says.
"Also, although USDA [US Department of Agriculture] agencies continue to collect use data through existing surveys of producers, data from these surveys provide only a snapshot of antibiotic use practices," it says.
Further, the agencies' data on resistance are not representative of food animals and meat across the nation and, because of a change in sampling method, in some cases have become less representative of the national picture since 2004, the GAO concluded.
The report says that a voluntary process that the FDA implemented in 2003 to assess risks associated with new antibiotics for animals is working reasonably well, but the process for limiting risks related to older antibiotics has problems.
In 2003 the FDA issued guidance to help drug sponsors evaluate potential risks to human health associated with new animal antibiotics. FDA documents say this guidance has been effective in limiting risks, according to the report. In addition, representatives of some producer, public health, and veterinary groups, along with an animal pharmaceutical organization, told the GAO they were "generally satisfied with the risk assessment approach," though they raised some concerns.
However, most of the antibiotics used in food animals were approved before 2003, the report says. Citing the enrofloxacin case as an example, FDA officials said that conducting post-approval risk assessments for all those drugs would be "prohibitively resource-intensive" and cause further delays.
Consequently, in 2010 the FDA proposed a voluntary strategy to promote the "judicious use" of animal antibiotics, instead of conducting risk assessments for individual older drugs. In line with that, the FDA is meeting with antibiotic sponsors in an effort to persuade them to voluntarily phase out growth-promotion uses of the drugs. Also, the FDA hopes to increase veterinary oversight of antibiotic use, by inducing sponsors to voluntarily change the status of antibiotics now used in feed from over-the-counter to "veterinary feed directive," meaning veterinary supervision would be required.
These voluntary approaches have raised various concerns among groups on both sides of the issue, including producer and veterinary organizations, drug makers, and public health groups, according to the report. For example, public health groups are worried that pharmaceutical companies simply won't cooperate.
The GAO said the FDA has no way to determine if its voluntary strategy is working. "FDA does not collect the antibiotic use data, including the purpose of use, needed to measure the strategy's effectiveness," the report states. FDA officials said they will consider the program a success when all growth-promotion uses of medically important antibiotics are phased out, but they don't have a timeline for that, it adds.
In other points, the report says the federal agencies have taken some steps to study alternatives to current antibiotic use practices and educate producers and veterinarians on appropriate use of antibiotics. However, all the education programs except one $70,000 USDA project have been phased out.
The GAO also took a look at practices and results in Denmark, which has much more restrictive policies than the United States on antibiotic use in food animals. Danish officials said their data on antibiotic resistance in food animals and retail meat show reductions in resistance after policy changes in most cases, the report says. However, officials have not found a decrease in antibiotic resistance in humans after implementation of the restrictive policies, except for a few limited examples.
An official of the American Veterinary Medical Association (AVMA) told CIDRAP News that the findings and recommendations in the GAO report are in line with what the AVMA has been saying about the issue of antibiotic use in food animals and antimicrobial resistance.
"I didn't find anything I thought was particularly new or surprising," said Christine Hoang, DVM, MPH, the AVMA's assistant director for scientific activities. "It's very consistent with things the AVMA has said repeatedly before, that there's a huge lack of information. It's also very consistent with a GAO report issued in June, addressing the human side."
She said the AVMA has long taken the position that much more information is needed to properly assess the relationship between antibiotic use in food animals and resistance trends in humans, adding, "I think the GAO simply reiterated that."
Hoang said the kind of increased data collection recommended by the GAO would be possible but difficult. "I think the issue has always been a lack of funding. Certainly the infrastructure needed for that type of monitoring and surveillance is rather difficult, but it's not an impossible task," she said.
An official with the Animal Health Institute, which represents companies that make antibiotics and other drugs for use in animals, told CIDRAP News that he didn't find any surprises in the report, either.
"The report doesn't say much that's new or ground-breaking," said Ron Phillips, the institute's vice president for legislative and public affairs. "What's notable is what it doesn't say. It doesn't support the kinds of legislative bans that have been proposed, and it does recognize that the FDA is currently involved in a collaborative process to further tighten antibiotic use" in animals.
He added that the institute believes the FDA's voluntary approach is the best way to achieve goals without incurring unintended consequences, such as increased death and disease in animals.
Phillips said the recommendations for gathering more data are "fine," but added, "FDA already gathers data on antibiotic use in animals; we're quoted in the report as saying national level data is less useful than local data that can be compared to local resistance trends. USDA once had a program to do that, but they abolished it. That's the kind of data collection that produces management information for producers and farmers so they can make the decisions about how to use antibiotics."
Jul 29, 2005, CIDRAP News story on FDA move to ban enrofloxacin use in poultry
June 2011 GAO report on antibiotic resistance in humans