LETTERS
edited by Jennifer Sills
LETTERS I BOOKS I POLICYFORUM I EDUCATION FORUM I PERSPECTIVES
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COMMENTARY
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Antibiotics: Discontinue
Low-Dose Use
IN HIS EDITORIAL “TIME TO DEAL WITH ANTI-
biotics” (15 November 2013, p. 777), D.
Kennedy correctly calls again (as he did in
the 1970s) for curbs on the overuse of antibiotics on industrial farms, where excessive
animal crowding has favored the likelihood
of disease and the perceived need to rely on
low-dose prophylactic antibiotics to stifle
outbreaks.
It is critical to recognize that veterinari-
ans must continue to have access to effective
antibiotics to treat animals that are clinically
ill from bacterial infections. Such treatment
entails the targeted use of therapeutic doses
for short periods of time at concentrations
that are capable of achieving high bacterial
kill rates. However, the practice of routinely
administering antibiotics at low-dose con-
centrations in feed and water for extended
periods of time to large populations of ani-
mals that lack signs of clinical illness is the
surest way to spawn resistant bacteria (1).
Even more threatening, and many would
say unethical, has been the industry’s use of
low-dose antibiotics for purposes of growth
promotion in healthy animals.
Although the FDA has recently determined the use of antibiotics for growth promotion to be injudicious, it continues to
condone the use of low-dose antibiotics in
feed and water for disease prevention (2).
Kennedy states that the FDA Guidance for
Industry #213 “would end antibiotic use for
growth promotion” and restrict prophylactic use in feed and water to veterinary prescriptions, but it must first be recognized
that this is a guidance document only and
has no enforcement authority. Furthermore,
if low-dose concentrations of antibiotics continue to be allowed for preventive
use (even by prescription), they provide a
“back door” through which growth promotion effects can still be exploited under
another name, thereby incentivizing industry to secure the needed prescriptions and
essentially continue business as usual. In
this respect, Kennedy’s enthusiasm for the
new FDA guidelines may be overly optimis-
Antibiotics: Call for Real Change
IN HIS EDITORIAL “TIME TO DEAL WITH ANTIBIOTICS” (15 NOVEMBER
2013, p. 777), D. Kennedy mentioned our assessment of the impact
of the Pew Commission on Industrial Farm Animal Production
(IFAP) (1). We support his call to end the misuse of antibiotics in
animal agriculture. We believe, however, that finalization of the U.S.
Food and Drug Administration (FDA) guidance documents will not
have a meaningful impact on the way these life-saving drugs are
administered to animals; thus, they will not slow the
contribution of IFAP to our rapid progression toward
a postantibiotic era.
These guidances—nonbinding pleas for the coop-
eration of drug companies—do not call for an end to
the use of antimicrobials in the absence of a microbial
disease or documented disease exposure, as recom-
mended by the Commission (2). Instead, they would
effectively rebrand uses currently labeled “growth pro-
motion” as “disease prevention.” Like growth promotion, prophylac-
tic uses entail low, subtherapeutic doses and can span much of the ani-
mal’s life span. They apply continuous selective pressure for antibiotic
resistance and may even induce new resistance-conferring mutations
(3). Furthermore, the FDA’s proposal for veterinary oversight would
eliminate the federal requirement that a valid “veterinarian-client-
patient relationship” exist before veterinarians order the use of antibi-
otics in feed, allowing veterinarians to prescribe antibiotics for use at
operations they have not visited recently for administration to animals
they have never seen.
The head of a large drug company recently told The Wall Street
Journal that the guidances will not substantially affect revenues (4),
implying that minimal changes to antibiotic sales are expected. This
explains why companies support voluntary limits on their products:
The limits will have little practical effect.
We share Kennedy’s assessment of the problem, but instead would
call for meaningful regulation—comparable to what he attempted as
FDA commissioner almost four decades ago—to curb irresponsible
antibiotic use. If such efforts fall short, legislative relief is needed.
KEEVE E. NACHMAN,* TYLER J. S. SMITH, ROBERT P. MARTIN
Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health,
Baltimore, MD 21205, USA.
*Corresponding author. E-mail: knachman@jhsph.edu
References
1. Johns Hopkins Center for a Livable Future, “Industrial Food Animal Production in America:
Examining the Impact of the Pew Commission’s Priority Recommendations” (Johns Hopkins
Bloomberg School of Public Health, Baltimore, MD, 2013); www.jhsph.edu/research/
centers-and-institutes/johns-hopkins-center-for-a-livable-future/_pdf/research/clf_reports/
CLF-PEW-for%20Web.pdf.
2. Pew Commission on Industrial Farm Animal Production, “Putting Meat on the Table:
Industrial Farm Animal Production in America” (Johns Hopkins Bloomberg School of Public
Health, Baltimore, MD, 2008); www.ncifap.org/_images/PCIFAPFin.pdf.
3. D. C. Love, M. F. Davis, A. Bassett, A. Gunther, K. E. Nachman, Environ. Health Perspect.
119, 279 (2011).
4. P. Loftus, “Zoetis chief leads animal-health firm following split from Pfizer,” Wall Street
Journal (2013); http://online.wsj.com/news/articles/SB100014240527023037555045792
07710851450896.
