According to a new analysis of data from the Food and Drug Administration (FDA), up to 80 percent of raw meat sold in US grocery stores contains antibiotic-resistant bacteria from species that can cause food poisoning. Is this really the case?
Commercially raised animals have been fed staggering amounts of antibiotics for decades, driving the evolution of antibiotic-resistant bacteria and putting these potentially dangerous pathogens right on our dinner plates. One would think that the increasing outcry from the scientific community – and concerned public – would have led to recent improvement, yet the Environmental Working Group (ERG)'s new examination of the FDA’s 2015 National Antimicrobial Resistance Monitoring System (NARMS) report suggests that the situation is not improving.
Back in 2013, the EWG performed a similar deep dive on the agency’s 2011 NARMS data. They calculated that 81 percent of ground turkey and 55 percent of ground beef samples taken from markets across the country tested positive for antibiotic-resistant strains of Salmonella and Campylobacter, whereas over 50 percent of chicken contained resistant Escherichia coli.
After the review was published, the FDA publicly responded, making some fair points in their argument that the EWG had oversimplified the data.
“EWG’s evaluation of the NARMS findings does not take into account important differences between various forms of bacteria and antibiotics,” the agency said. “The EWG report cites some pathogens that don’t lead to food-borne illnesses or focuses on resistance to antibiotics that are not commonly used to treat sick people. Furthermore, it is alarmist to imply that pathogens resistant to one, or even a few, antimicrobials should be called ‘superbugs’ – if these same bacteria are still treatable by other commonly used antibiotics.”
It’s true that the NARMS statistics are difficult to decipher due to the way the data is presented, forcing the EWG to do some number crunching of their own in order to present easily digestible percentages of how many samples from each type of meat harbored resistant microbes. And while we have no intention of downplaying the danger of acquired bacterial resistance and the dire necessity of curbing overuse of antimicrobial drugs both in livestock and humans, it is also important to avoid cherry-picking information when writing to the public.
Their interpretation of the 2015 report, which was released in 2017, splashily declares that 73 percent of strains of Salmonella cultured from ground turkey samples collected in 2014 were resistant to at least one antibiotic, but does not mention that the proportion dropped to 57 percent the following year. The percentage of resistant Salmonella found in retail chicken meat remained steadier: 59 percent in 2014 and 57 percent in 2015.
Furthermore, rates of Salmonella strains resistant to three or more antimicrobials – a much more relevant marker of resistance given that some strains are naturally resistant to certain agents – appear to be a downward trend after several years of worrying increase. In 2011, 41 percent of chicken and 43 percent of ground turkey samples had strains meeting these criteria, yet in 2015, the figures were 15 and 30 percent, respectively.
Next, the EWG highlighted that, on average, 1 in 5 strains of Salmonella found on grocery store chickens in the past 5 years were resistant to amoxicillin (a type of penicillin that is essential due to its safety in children and pregnant women). While this is mathematically true, the organization does not mention that the rate has halved, from 33.3 percent in 2010 to 13.1 percent in 2015.
Data on Campylobacter – a genus that evolved to infect poultry but can cause severe illness when spread to humans – indicates that both of the main strains found on market chicken were either increasingly resistant or remained at steadily high rates of resistance to ciprofloxacin – one of the most commonly prescribed broad-spectrum antibiotics – between 2013 and 2015. The report notes that fluoroquinolones, the class of antibiotics that ciprofloxacin belongs to, have not been approved for use in poultry since 2005; yet clearly, the animals are being exposed somehow.
The percentage of Campylobacter strains no longer susceptible to erythromycin – another heavily relied upon medication – has also shot up since 2013.
As for the prevalence of resistant E. coli in supermarket meat, the NARMS data shows that 57 percent of ground turkey, 31 percent of chicken, 12 percent of pork chops, and 7 percent of ground beef samples contained strains resistant to three or more antimicrobial classes. The rates have remained more or less steady for all sources over the past 13 years.
In another factoid that lacks proper context, the EWG article states that “87 percent of the indicator bacteria found on ground turkey by FDA scientists was resistant to tetracyclines – the most used antibiotic in food animals despite being designated by the World Health Organization as a ‘highly important’ class of antibiotic.” The author does not mention what year or strains they refer to, nor do they mention that we have known for over a decade that a large proportion of all the gram-negative bacteria species that may infect people have become resistant.
According to the government report, the quantity of these drugs sold for use in food-producing animals in the US increased 26 percent between 2006 and 2015. There is no justifiable answer for why use is going up.
It is now widely frowned upon to feed animals antibiotics in order to promote growth, but many in the industry still pump animals full of drugs through dosed feed and water in order to ‘prevent illness’ – and do so legally. This practice has exacerbated bacterial resistance so greatly, that in 2017, the World Health Organization issued fresh guidelines vehemently urging farmers to administer antimicrobials only when a herd or flock is in true danger. Lobbyists for the industry and the Trump administration pushed back immediately.
The FDA declined to comment to IFLScience on the latest EWG report, but did write to us.
"Already, the FDA has fostered antimicrobial stewardship in the veterinary setting, eliminated the use of medically important antimicrobials in food-producing animals for growth promotion purposes, and both limited therapeutic use of these drugs to legitimate animal health needs and placed them under veterinary oversight," they said.
"The FDA recognizes that antimicrobial resistance is a critical public health issue, and the agency has already taken actions designed to slow the development of resistant bacteria, while understanding that more work needs to be done."
Now, please remember to buy antibiotic-free meat (here’s a guide) before we are all wiped out by a superbug.