FDA Updates Guidance on Antibiotic Use in Livestock

The U.S. Food and Drug Administration (FDA) just announced that the implementation process is complete for their “Guidance for Industry #213.” It’s a vague and unimpressive title, but the goal of this new guidance document is an incredibly important one: phasing out the casual use of antimicrobial drugs in livestock, in order to combat emerging bacterial resistance.

Many years of negotiations between the FDA and important stakeholders in the agricultural and pharmaceutical industries has led to the release of this new guidance document, which spells out the appropriate and acceptable agricultural uses of antimicrobial drugs currently used in humans. Called medically-important antimicrobials, many of these drugs are critical to fighting serious human infections, especially in this era of increasing antibiotic resistance in the microbes that cause human disease.

New FDA Guidelines for Livestock Antibiotics

According to the FDA’s January 3rd statement on GFI #213:

Of the 292 new animal drug applications initially affected by Guidance for Industry #213:

  • 84 were completely withdrawn
  • Of the remaining 208 applications,
    • 93 applications for oral dosage form products intended for use in water were converted from over-the-counter to prescription status,
    • 115 applications for products intended for use in feed were converted from over-the-counter to veterinary feed directive status
    • Production (e.g., growth promotion) indications were withdrawn from all (22) applications that included such indications for use

The release of GFI #213 means that the agricultural industry has agreed to end the practice of “growth promotion,” which is the addition of small amounts of antibiotics to animal feed in order to accelerate the growth of livestock. As anyone who’s been prescribed antibiotics knows, taking too small a dose for too short a time contributes greatly to resistant organisms, as the bacteria who are resistant to the low dose are allowed to thrive and multiply. When they multiply in a herd of animals, they can – and often do – find their way to us.

Unfortunately, the same bacteria that live in the bodies of livestock can also cause serious infections in human populations. Outbreaks of E. coli, Salmonella, and Listeria bacteria are common, and casual antibiotic use in their animal hosts increases the chances that it will be resistant forms of these bugs that find their way into our food and water.

When Antibiotics Can Be Used in Livestock

Of course, livestock isn’t immune from infection, and outbreaks in large herds or flocks are common. There is no law against treating your animals with antibiotics if they acquire infections – to deny the animals treatment would be cruel. However, in many cases, sick animals are treated with human-use antibiotics.

With the new guidance, medically-important antimicrobials will now only be available for use with a prescription, under the oversight of a licensed veterinarian. Previously, farmers and ranchers could obtain antimicrobial drugs for veterinary use via the internet with no prescription, opening the door to misuse and antimicrobial resistance. Unfortunately, though, the drugs in question are still available for purchase online, and the rules against their use may be difficult to enforce.

One of the most glaring problems with the guidance document is that it still allows for the preventative use of medically-important antimicrobials. it’s very common for animals to be treated with these drugs prophylactically, to prevent the spread of infection through the entire herd or flock. That has the unfortunate effect of making those antibiotics less effective in human infections, as there is a greater chance that organisms will have acquired resistance.

That’s a rather large loophole, and it may mean that the years of work put into developing the guidelines won’t pay off in the way that the FDA intended. Similar guidance on antibiotic use in livestock went into effect in Europe in 2006, and so far there has been no obvious decline in the emergence of resistant organisms in humans. Sales of antibiotics for use in livestock haven’t significantly declined, and a recent report found that over 91% of the antibiotics used on European farms are for disease prevention rather than treatment, and are used on entire herds and flocks through their addition to animal feed or drinking water.

While the rules laid out in GFI #213 are an encouraging step in the right direction, it’s easy to argue that it doesn’t go far enough to protect the small group of last-resort antibiotics needed to save human lives.

Of utmost concern is an antibiotic called colistin, which is one of the very last drugs that can be relied on when organisms are resistant to everything else. Casual use of colistin in animal populations for prevention of disease has created a mutant, resistant organism which has now turned up in 32 countries, including the US. Alarmingly, the specific type of resistance that the organism has evolved is a form that is transferable to other species of bacteria, amplifying the danger.