Healthy Paws: Antibiotic Use in Pets

Editor’s Note: Healthy Paws is a column sponsored and written by the owners of Clarendon Animal Care, a full-service, general practice veterinary clinic and winner of a 2017 Arlington Chamber of Commerce Best Business Award. The clinic is located 3000 10th Street N., Suite B. and can be reached at 703-997-9776.

November 13-19 has been declared World Antibiotic Week. While at first glance it might be easy to roll your eyes at this, think about how much antibiotics have done for health and medicine over the last century, and you’ll see few things are more deserving of their own week than antibiotics. Antibiotic, by definition, means “opposed to life” — specifically the life of bacteria. Antibiotic is often used interchangeably with the term antimicrobial, but antimicrobial refers more generally to all microorganisms (bacteria, viruses, fungi, protozoal organisms)

The original antibiotic, penicillin was first discovered by biologist Alexander Fleming in 1928, purified by Ernst Chain, Howard Florey and Edward Abraham in 1942, and further developed for wide-scale production by Norman Heatley. Penicillin arrived on the scene just in time to be the decisive factor in saving countless lives during World War II, and it’s difficult to overestimate the importance of antibiotics since then. However, as “bigger and better” antibiotics have been developed in the 89 years since their initial discovery, many of the bacteria they are targeting have also developed coping mechanisms or resistance to the antibiotics designed to destroy them.

Antimicrobial resistance (AMR) is the ability of a microbe (which includes bacteria, viruses and certain parasites) to prevent an antimicrobial agent from working against it. This has become an increasingly serious problem as microbes develop resistance against more and more antimicrobials and is seen with all kinds of microbes — not just bacteria. While all resistance is a concern, antibacterial resistance typically receives the most attention as bacteria account for so many of the infections seen worldwide, both in humans and animals.  

One of the ways that health care professionals, including veterinarians, determine if a bacterial infection is resistant to common bacteria is to “culture” the organism and perform sensitivity testing — in this process the organism is grown on a petri dish in a lab and various antibiotics are tested against it to see which are effective and which are ineffective at hindering growth in a lab setting. Ideally, all suspected bacterial infections would be cultured; however, from a cost, time and resources standpoint this is not often practical and often health care professionals need to make an educated guess about which antibiotic would be most appropriate for the type of infection they are treating.  

Many of the general recommendations from human medicine for decreasing the chances of resistance apply to veterinary medicine as well:

• Antibiotics should only be used when prescribed by a licensed health professional.
• The full course of antibiotics should be finished, unless otherwise directed by a health professional.
• Antibiotics should not be shared with other people or animals.
• Left-over antibiotics should not be used for similar signs down the road, unless under the direction of a health professional (and if they were used for the full course initially, there shouldn’t be any leftover regardless).

On the veterinarian/prescriber end of things, the following should be abided by:

• Antibiotics should only be prescribed when there is proven bacterial infection, or very high index of suspicion for such.
• Antibiotics should be prescribed for a sufficient length of time so as to fully address the infection.
• “Bigger gun” antibiotics should be reserved only for infections in which other antibiotics are ineffective, preferably based on culture and sensitivity results.
• If bacterial cultures are not used from the initial diagnosis — they should be implemented at the first signs of initial treatment failure so targeted therapy can be instituted quickly.

Antibiotic resistance is something we all (veterinarians, human healthcare professionals, and recipients) need to work toward reducing as the rate of new antibiotic development has tapered to a trickle; and overuse and inappropriate use has contributed greatly to the widespread resistance problems.