Antibiotic
stewardship: not a burden for animal agriculture alone
By Bill Hsu
Incidence of antibiotic
resistant bacterial infections are higher than ever, and the Centers for
Disease Control and Prevention (CDC) note that at least 23,000
people die each year as a direct result of these infections. It’s no wonder then, that fears of rampant
superbugs are fueling the debate about responsible antibiotic usage, and much
of the talk centers around antibiotics used in animal agriculture. The same fungi spores that bore our first
antibiotics find other use in the food industry though. After all, it does take Penicillium to make blue cheese or Roquefort. Much like some cheeses though, the debate
surrounding is chock full of holes.
California
Senate Bill 27 (SB27) was signed October 2015 to combat what was described
as widespread and unregulated use of antibiotics in animal agriculture at low
or sub-therapeutic doses to increase weight gain in animals before they went
off to slaughter. SB27 expressly
prohibits use of medically important antibiotics in animals unless they were
prescribed by a veterinarian. It also
bans the use of antibiotics used for growth-promotion.
SB27 references the Food and Drug Administration’s Guidance
for Industry Document #152 (GFI 152). These are rules the FDA proposed to classify
different antibiotics important in human medicine into three categories:
important, highly important, and critically important. The list is extensive and includes highly
specific-use antibiotics, as well as broader spectrum antibiotics that you
might get from your doctor if you have a small infection. This list, however comprehensive, is mostly
meaningless in trying to limit antibiotic usage in California’s food producing
animals.
Antibiotics generally have multiple indications on their
label. Macrolides and tetracycline are
both classes of antibiotics that make an appearance on GFI 152. These classes of antibiotics are also some of
the most commonly used antibiotics in animal agriculture. Based off those two facts alone, you’d
suspect that using these two classes of antibiotics to promote weight gain is
rampant in animal agriculture, but you’d be wrong. You see, these antibiotics have several
indications on their label.
When a licensed veterinarian writes a prescription, or in
this case, assigns a feed directive for a farm, he or she is prescribing the
same antibiotics we mentioned were used to promote weight gain in
animals—albeit, in higher concentrations.
You read that right—when you’re treating animals to prevent disease in
areas of exposure risk, you’re using the more of the same antibiotics you were
trying to limit use of!
But does it even matter?
The Summary
Report on Antimicrobials Sold or Distributed for Use in Food-Producing Animals
from the FDA highlights that the two largest classes of antibiotics used
domestically in agriculture are tetracycline (which
you or I can buy today) and ionophores, which serve no function at all in
the human body. Together, these two
account for about 3/4th of all antibiotics used in agriculture. Our most valuable antibiotics, those
classified as critically important in human medicine, including 3rd
generation Cephalosporins and Flouroquinolones, see the heaviest usage in
healthcare. In fact, each of these
account for less than 1% of usage in animal agriculture. The fear of prolific superbugs spelling our
demise is driving action like SB27, but the
CDC spells it out clearly—most
deaths related to antibiotic resistance happen in healthcare settings such as
hospital and nursing homes.
Antibiotic stewardship is a responsibility we all
share. With the discovery of penicillin,
antibiotics have shaped what we know of modern medicine. Antibiotics are powerful tools, but have a
very finite practical life. Investment
in alternative
practices in animal agriculture, including vaccines and animal management
can help draw down total usage numbers.
Physicians dialing back antibiotic scripts, except in the most important
cases can help prevent abuse of our most essential antibiotics. Finish
your antibiotics as prescribed. Don’t flush extra pills
down the drain. A concerted effort
to managing antibiotics, from all fronts, is necessary to address growing
threats of resistance.
Attention spans are short and opinions are heard louder than
ever. Shifting the focus solely to
agriculture while ignoring healthcare data, or making only symbolic attempts at
bandaging the very real problem of overuse of antibiotics, especially of those
critically important in human medicine, mean we will someday lose our best
tools in healthcare. Remember that for
the future, whether it’s a doctor’s office you find yourself in or the meat and
cheese display at your local deli.
