Yesterday, I saw two limping dogs. Both had injured a toe – one in an accident with a door and the other in some unknown traumatic event resulting in a swollen toe with a fractured nail. My treatments were simple for both dogs: clip the fur on the one with the scraped toe, and for the second dog, I trimmed off the fractured nail and covered the paw with a medical boot to prevent licking. After the dogs left my office, I started to worry. Should I have prescribed antibiotics?

Appropriate antibiotic prescriptions

Antibiotics are only effective in treating infections caused by bacteria. Not every bacterium is killed by every antibiotic. The best way for me to select an antibiotic is based on a laboratory test called a culture and sensitivity. For this test, I submit a sample of the infected material (urine, abscess or biopsy) to the lab. They isolate and identify the bacteria. The lab then tests a panel of antibiotics against the bacteria to identify the best one to treat your pet’s infection. If I am highly suspicious of an infection, I will make a best guess as to an appropriate antibiotic and treat while I wait for the results of the culture and sensitivity.

Inappropriate antibiotic prescriptions

Infections caused by viruses do not respond to antibiotics, such as feline upper respiratory infections  and canine influenza.
If your dog has had the flu, he may have been treated with antibiotics, but only if the flu had allowed a bacterial infection in the lungs or pneumonia.

The risk is resistance

Why did I not prescribe antibiotics for my two canine patients with toe injuries? Unnecessary antibiotic use is responsible for creating bacteria resistant to antibiotics. Neither dog had evidence of an infection and both dogs felt well except for their toe. One dog had the canine version of a skinned knee and I am sure is already better today. The other dog probably had the fractured toenail for close to a week and it had not become infected. The medical boot I prescribed provided a barrier against infection.

The downside of antibiotics

You might ask is there harm in giving an antibiotic to these dogs as a preventive measure. All drugs cause adverse effects. Vomiting and diarrhea are common adverse effects from antibiotic therapy. My job is to make pets feel better, not worse. When there is no infection, an antibiotic might make your pet feel worse. The greater harm is creating resistant bacteria by prescribing antibiotics when they are not needed. When your pet really needs an antibiotic, I won’t have one that works due to resistance induced by unnecessary antibiotics.

What can you do?

If your veterinarian prescribes antibiotics for your pet, give them exactly as prescribed. Discontinuing antibiotic treatment early increases the risk of inducing antibiotic resistance without eradicating the infection.