Urinary tract infections (UTIs) are a common problem in dogs, especially female dogs. UTIs are also a common reason for antibiotic use in dogs. Unfortunately the use of antibiotics for canine UTIs is commonly inappropriate, in one way or another – in some cases the drug selected is inappropriate, while in others the length of treatment may be the problem. These mishaps may occur for many reasons, including failure to perform urine cultures, stopping treatment too early because the animal looks better, or not being prescribed an appropriate duration of treatment.
Urine culture is very important. Culture can confirm that an infection is present and help guide antibiotic therapy so the infection gets treated as effectively as possible. Urine culture should be done on every animal with a UTI, not just those that have not responded to initial treatment. If a culture is taken when the animal first develops the infection, there is probably less chance that the infection will recur. If it does recur, another culture can determine whether the same bug is involved – sometimes animals will have repeated infections with different bacteria, indicating that there may be an underlying condition making them extra susceptible to infection (e.g. diabetes, Cushings syndrome). Repeated infections with the same bacterium suggests that the infection was never completely eliminated, and that a longer course of treatment might be needed, or that there might be something reducing the effectiveness of the treatment, such as a bladder stone.
A major problem with treatment of UTIs is stopping treatment too early because "the dog looks better." In animals with a UTI, the signs of disease (e.g. frequent urination, straining, bloody urine) may resolve before the infection is completely eliminated. Stopping treatment too soon can allow the infection to come back. That means the animal will be sick longer, and it will be more expensive (another visit to the veterinarian, more antibiotics, and (more) urine culture(s)).
We don’t really know how long to treat UTIs in dogs. Dogs are often initially treated for 7-14 days for a UTI. Standard recommendations for treating UTIs in people used to be 7-10 days, but nowdays only short courses are used (and appear to be effective). It’s unclear whether we should change the way we treat dog UTIs in a similar manner. In an otherwise healthy dogs with a first-time UTI, shorter treatment is probably reasonable. Too short of a treatment period can cause its own problems, however, as discussed above.
Early diagnosis and treatment are important. The longer the infection festers, the greater the chance of a deeper infection in the bladder (which may be harder to eliminate) and the greater the chance of complications such as bladder stones. Not to mention it’s no fun for anyone (dog or owner) to have a bladder infection, so don’t let it get any worse!
Some dogs have recurrent UTIs because of issues such as bladder stones and neurological dysfunction. Typically, all the antibiotics in the world won’t fix these problems. If there is an underlying cause, that needs to be addressed first. There’s no use continuing to use antibiotics when treatment will be ineffective and antibiotic resistance will possible emerge.