Peer-reviewed veterinary case report
Quick test for ampicillin-resistant UTIs in dogs and cats
By Brookshire, W Cooper et al.·Published in Journal of veterinary internal medicine·2025·Mississippi State University College of Veterinary Medicine, United States·View original on PubMed →
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Original publication title: Evaluation of a Rapid, Low-Cost Broth Turbidity Test for Detecting Ampicillin-Resistant Lower Urinary Tract Infections in Dogs and Cats.
Plain-English summary
A study tested a new, low-cost method for detecting urinary tract infections (UTIs) caused by bacteria resistant to ampicillin in dogs and cats. Researchers analyzed urine samples from 145 dogs and 15 cats, finding that this broth turbidity test was highly effective, correctly identifying resistant infections 89% of the time and accurately ruling out susceptible infections 100% of the time. This quick test could help veterinarians make faster treatment decisions, although it may not be as reliable in cases with very low bacteria levels or if the pet has recently been treated with antibiotics.
People also search for: dog urinary tract infection treatment · cat UTI symptoms · ampicillin resistance in pets · how to test for UTI in dogs · low-cost UTI test for cats
Abstract
BACKGROUND: Effective treatment of urinary tract infections (UTIs) in dogs and cats relies on timely recognition of antimicrobial resistance, but traditional microbiological culture and susceptibility testing require 48-72 h and can be cost-prohibitive. OBJECTIVE: To evaluate a novel, low-cost broth turbidity test for detecting ampicillin-resistant UTIs in dogs and cats compared to the gold standard microbiological methods. ANIMALS: One hundred sixty urine samples from 145 dogs and 15 cats at the Mississippi State University College of Veterinary Medicine. METHODS: From September 2023 to February 2024, urine samples were tested using an ampicillin-supplemented Mueller-Hinton broth turbidity test and gold standard culture with Sensititre MIC plates. Sensitivity, specificity, Cohen's κ, and McNemar's test were calculated. RESULTS: The broth turbidity test showed 89.47% sensitivity (95% CI: 66.86%-98.72%) and 100% specificity (95% CI: 97.42%-100%) for the detection of ampicillin-resistant organisms in the urine, with substantial agreement (κ = 0.94, p < 0.001) and no classification difference (p = 0.500). Notably, all 36 samples with ampicillin-susceptible organisms identified by the gold standard cultures test were correctly identified as negative for ampicillin resistance by the broth turbidity test. CONCLUSIONS: The broth turbidity test's simplicity and affordability make it a promising tool for in-house use by veterinary practitioners to guide first-line therapy decisions, though its sensitivity could be limited in cases with low bacterial loads or confounding factors such as recent antibiotic administration.
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Search related cases →Original publication on PubMed: https://pubmed.ncbi.nlm.nih.gov/41035374/