Table 1 Summary of inclusion and exclusion criteria

The study assesses the population (P) and disease of interest.

We only included studies which assessed experimentally induced (which refers to introducing bacteria to establish a UTI in a healthy laboratory animal) or sporadic bacterial cystitis (also called simple UTIs) in dogs and cats, meaning animals must be healthy. No restrictions on breed or age of animals were applied.

Studies that considered other animal species or humans were excluded. Studies in unhealthy dogs or cats (animals with underlying anatomic, functional or systemic diseases which might predispose them to UTIs) or those with recurrent bacterial cystitis (meaning 3 or more sporadic bacterial cystitis events in the past 12 months or two or more events in the past six months¹⁵), prostatitis or pyelonephritis were also excluded.

The study compares (C) the impact of treatment (I).

To be included the study must have compared the impact of antibiotic treatment durations (and report type of antibiotic, dose and duration of treatment) on spontaneous or induced urinary tract infections. Studies also must have compared the same antibiotic and drug for both arms/comparison groups. Studies could compare any antibiotic durations; to prevent exclusion of relevant studies (i.e., those which might compare 7-to-10-day durations) we compared efficacy of antibiotic durations continuously across a 1 day to > 14-day duration range.

Additionally, studies examining any antibiotic type and any routes of administration (PO, IM, IV or SQ) were eligible for inclusion.

If the study reported on the impact of antibiotic treatment on a different disease such as prostatitis, or pyelonephritis it was excluded. Studies which reported on use of antibiotics for prophylaxis of UTI were excluded. Studies which compared different antibiotics in each arms/comparison group were excluded.

The study assesses a primary outcome (O) +/- secondary measures of interest.

Studies needed to report on the primary outcome of interest: clinical or microbiological resolution of a sporadic or induced urinary tract infections in dogs or cats 1 to 14 days after treatment as defined by authors. Secondary outcomes included long term (14 to > 30 day) clinical or microbiological cure rates, mortality and any adverse events reported.

If the study did not report on clinical or microbiological resolution of urinary tract infections, it was excluded.

The study design meets methodological requirements [19].

To be included studies had to be peer-reviewed. Due to an anticipated low number of RCTs performed on this topic, observational studies such as nonrandomized controlled trials, case-control or cohort studies were also included. We also opted to include published abstracts.

Qualitative study designs, editorials, reviews, commentaries, case series, case reports, pre-prints, study protocols, dissertations, and posters were excluded.