AHI Open Letter to Scientific American

February 2, 2017

Mariette DeChristina

Editor in Chief

Scientific American


Dear. Ms. DiChristina:

I am writing to express our surprise and disappointment with your recent article “How Drug-Resistant Bacteria Travel from the Farm to Your Table” written by Melinda Wenner Moyer.  The issue of antibiotic resistance is a scientifically technical and nuanced issue with more questions than answers.  We hoped a scientific publication like yours would be able to fairly handle these technicalities and address the nuances and unknowns for readers in a fact-based approach.  Instead, the piece resorts to a distinct narrative attempting to alarm readers.

The headline speaks of bacteria traveling from farm to table – which are what we call foodborne bacteria, particularly Salmonella and Campylobacter.  The 2013 Threat Report from the Centers for Disease Control places these threats – those that might come from animals – in proper perspective.  In the report, CDC described 18 bacteria that comprise the antibiotic resistance threat, and properly listed only those two foodborne pathogens as those that might come from animals.  And thanks to 20 years of government monitoring – information shared with your writer but not reflected in the story – we know a great deal about the risk of these pathogens.  The 2014 Integrated Report for the National Antimicrobial Resistance Monitoring System (NARMS) shows that trends continue to improve both in the overall prevalence of foodborne bacteria and in the resistance rates to these bacteria.  For Salmonella:

  • 82 percent of Salmonella isolates from humans had no resistance to any tested antimicrobial, and this susceptibility rate has steadily increased since testing began in 1996.
  • Resistance in Salmonella to the most critically important antibiotics is generally low and declining. Quinolone resistance remains below 3 percent in turkeys and below 1 percent in chickens.
  • Multi-drug resistant Salmonella in humans and cattle HACCP samples declined to the lowest levels in 20 years.

In Campylobacter:

  • The presence of Campylobacter on retain chicken meat has declined 37 percent since 2003. No Campylobacter was found on retail turkeys in 2014.
  • Resistance in C. jejuni – the most common serotype – to erythromycin, an important macrolide and the antibiotic class of choice for treatment, remains low in humans and in chicken sources.

These results are consistent with recent papers published by a team of researchers at the Medical University of South Carolina, which performed a review of the current literature on these two foodborne pathogens.  The team found no conclusive evidence of a definitive link between the use of antibiotics in food animals and emergence of drug-resistant Campylobacter.  Concerns about Campylobacter were linked to drinking raw milk or eating food products made from raw milk.  Similarly, the Salmonella review found no study in recent literature that definitely links antibiotic use in animals to antibiotic resistant Salmonella.

Despite the existence of these data regarding foodborne bacteria and your headline referencing foodborne bacteria, the article focused on MRSA – which CDC has specifically said is not a foodborne bacterium.  This is a critical differentiation that should be made in a scientific publication.  There are distinct strains of MRSA in hospitals, in the community and in livestock.  Because this resistant bacteria emerged decades ago in hospitals, has spread through community settings and only more recently emerged in livestock, the origin of the livestock strain is likely a non-farm setting and not due to antibiotic use or other farm practices.  Your article fails to help readers understand that they need not be concerned about contracting MRSA from the food they eat.

This confusion was also evident in the discussion about MRSA in the Netherlands.  The paragraph opens with a reference to livestock-associated strains of MRSA, then follows up with a sentence about the “deadly” results of hospital acquired MRSA, failing to note they are entirely different strains.  The statement “…one-fifth of the Netherlands’ human MRSA infections were identical to bacteria that had come from Dutch livestock” is incorrect because in confuses “infection” with “colonization.”

The article fails to present a fact-based approach in discussing other bacterial threats also not connected to animals, or antibiotic use in animals. “Stripped of the power of protective drugs, today’s pedestrian health nuisances – ear infections, cuts, bronchitis – will become tomorrow’s potential death sentences.”

The article uses other terminology straight from activist literature to describe antibiotic use, including terms like “mass-feed” and “antibiotic-laced.”  An accurate description would have been useful for your readers:  All antibiotics are approved by FDA based on data submitted by companies.  Generally, these products receive a label claim for a specific dose aimed at a specific disease or pathogen, and antibiotics used in feed – whether they are prescribed by a veterinarian or not – must strictly follow those directions on the label.  Typical doses in feed range from 10 milligrams per ton to 50 milligrams per ton.

The article misleads readers on two important points regarding the current effort to implement the FDA Judicious Use Policy, by which the use of antibiotics similar to those used in humans will no longer be used to promote growth in animals and all the remaining uses will require the supervision of a veterinarian.  First, it says “most” companies have agreed to comply.  That has been false since April of 2013, when FDA announced that all companies with products subject to the new policy had notified the agency of their agreement to comply and, as of January, full implementation of the policy has been completed.  Second, the article confuses amount of use with label claims by referring to a “disease-control exemption.”  This does not exist.  There are no medically important antibiotics where current doses and durations are the same as those for prevention claims.  The use of medically important antibiotics for growth in animals has stopped as of January 1, 2017 and be strictly illegal thereafter.  As explained earlier, label directions for antibiotics in feed must be followed.  Current label claims for prevention uses typically list either a specific disease being addressed or a specific pathogen, and cannot be used unless a veterinarian says they are necessary.  Thus, the sentence, “…found that farmers will still be able to administer one quarter of the drugs at the same dosages with no limits on treatment duration – as long as they say they are using them to prevent or control disease” is not accurate.

The article’s focus on the overall amount of use in the wake of implementing the FDA Policy is again disappointing in a science publication.   As we explained, use amounts do not equate to increased resistance or risk.  The NARMS data demonstrate this point since antibiotics have been used for more than 40 years yet resistance has steadily decreased.  Some antibiotics, like the macrolide class, have been used for years and resistance in Camplylobacter to these antibiotics considered drugs of choice have remained exceedingly low.

The writer failed to consult other publications and perspectives on resistance in E.coli UTI’s.  We directed her to Randy Singer, who published an article on this topic in Frontiers in Microbiology, February 2015, Volume 6, Article 28, which states:

Many of the most important strains of human ExPEC globally, such as ST131, are highly virulent and clonal implying routes of transmission other than food.”

Taken in its totality, the link between ExPEC in animals and UTI in humans might exist, but studies conducted to date do not enable an estimation of the relative importance of this route of transmission.”

We are dismayed by the anti-agriculture viewpoint of this article.  The many biosecurity measures that the author describes to make the charge of “hiding” are in fact methods to ensure the animals are not subject to additional diseases from humans – including the MRSA that is highlighted in the article.  The author describes a USDA-FDA collaboration to collect more antibiotic use information, but fails to point out that effort is widely supported by agriculture, veterinary and animal health groups who joined with public health groups to lobby Congress to support funding for this effort.  In addition, the major species groups are collecting their own use data to share with USDA in support of this effort.

The agriculture community is nothing like the one described in your article.  Agriculture supports a One Health approach to the public threat of antibiotic resistance.   We have participated in the White House efforts to address this issue – including participation in the 2015 White House Forum on Combatting Antibiotic Resistance and serving on the President’s Advisory Council on Combatting Antibiotic Resistant Bacteria.   And the entire industry has worked for the past three years to be ready to fully implement FDA’s Judicious Use policy, ensuring that medically important antibiotics are used in food animals only to fight disease under the supervision of a licensed veterinarian.  We believe the availability of antibiotics to address disease threats in animals is important to a safe food supply and that those tools should be used only when necessary and in the amount necessary to fight disease.

We hope that in the future your publication will better reflect both the science and the significant steps being taken by the agriculture community to address this important public health issue.


Richard Carnevale

Vice President, Regulatory, Scientific and International Affairs


cc: Melinda Wenner Moyer