While the typical antibiotic treatment time for women with urinary tract infections (UTIs) usually ranges from one to five days, antimicrobial therapy for dogs with UTIs lasts two weeks.
Why is there such a difference in the length of treatment? This is an issue that Dr. Elisabeth Snead, an associate professor of small animal medicine at the Western College of Veterinary Medicine (WCVM), has wanted to address for several years.
"Compared to human medicine where many studies have been done, there has been minimal investigation in the veterinary field to determine the best course of treatment for UTIs in our patients," says Snead, who has a passion for solving clinical medical problems.
According to Snead, UTIs are one of the most common infectious conditions seen in canine patients, yet there's very little evidence-based medicine to support the current course of care.
Susan Mehain is a fourth-year veterinary student who participated in the WCVM's Undergraduate Summer Research and Leadership program in 2013. Susan's story is part of a series of articles written by WCVM summer research students.
"We treat our patients with antibiotics for two weeks because we really don't know if treating for shorter periods of time would be adequate. It's shocking that we don't have an answer to such a simple question."
In contrast, human medicine has been looking at ways to improve compliance since the early 1980s. Researchers have found that using short-term therapy works just as well as the standard three- to four-week protocol, but with the added benefits of lower costs, fewer adverse effects and increased compliance.
Short-term therapy could also help to reduce the emergence of antibiotic resistance.
Snead feels strongly that veterinarians owe it to their patients to understand what the standard of care should be.
"If we can make the treatment regimen more straightforward and it's going to do the same job, then that only has upsides."
During the summer of 2013 and throughout 2014, Snead is supervising a research project to determine if the antibiotic, nitrofurantoin, could become a feasible first-line choice for the treatment of UTIs in dogs. The study focuses on 12 female client-owned dogs that have a simple UTI with no underlying cause identified by evaluation of basic blood work, physical examination or ultrasound of the urinary bladder.
Dogs that meet the study's criteria are randomly assigned to one of two treatment protocols. Members of the research team, which includes Dr. Jewel Milo, a first year internal medicine resident in small animals, will give amoxicillin to the first treatment group for 14 days, which is the current standard of treatment in veterinary medicine. The second treatment group will be given a five-day, short-course therapy with nitrofurantoin.
"Amoxicillin is my first choice antibiotic to treat an uncomplicated UTI, and I chose to compare it to nitrofurantoin because I wanted to avoid using drugs that may increase antimicrobial resistance," explains Snead.
"Nitrofurantoin is a common first-line drug in human medicine for treating UTIs, and 98 per cent of E. coli — the bacteria responsible for the majority of canine UTIs — are susceptible to this drug."
After completion of treatment, the research team will obtain follow-up cultures and use them to demonstrate that bacteria are no longer present in the urine (a microbiological cure).
Researchers will confirm a clinical cure, or resolution of clinical signs, by gathering information from the pets' owners after treatment begins. The rates of cure will be compared between the two treatment groups.
"[These results] should help answer the question of whether or not veterinarians can treat simple UTIs with a shorter course of therapy with this antibiotic. If it is effective, maybe there are other types of infections that we could investigate as candidates for shorter courses of treatment as well," says Snead.
"Passing on clinically relevant research results to clinicians, whether the findings are good or bad, is very useful to help veterinarians make decisions when treating their patients."
If the study's results show that a shorter course of antibiotics is as effective for treating UTIs in dogs as a longer course of a more standard antibiotic, Snead hopes more veterinarians will consider adopting the shorter therapy protocol for their canine patients.
In the long run, that could help to ensure that owners have an easier time medicating their pets — and hopefully, will be more likely to give the complete course of treatment.
The University of Saskatchewan's Interprovincial Scholarship is providing funds for this research project.
Susan Mehain of North Vancouver, B.C., is a fourth-year veterinary student who participated in the WCVM's Undergraduate Summer Research and Leadership program in 2013.