Evaluation of the PA-100 AST system (Sysmex) for point-of-care analysis of bacteriuria and antibiotic susceptibility testing in dogs and cats.

Bacterial presence in urine (bacteriuria) is frequently observed in dogs and cats and may be associated with urinary tract infection (UTI), depending on the clinical context. However, no in-house test for the rapid detection of bacteriuria and subsequent antibiotic susceptibility tests (AST) is yet available. The Sysmex PA-100 AST System (PA-100) is a point-of-care (POC) analyzer using nanofluidic cartridges designed for the detection of bacteria and performance of AST directly from voided urine in female patients with cystitis symptoms. In this study, we tested the suitability of the PA-100 to detect UTIs and perform AST on veterinary samples. In total, 363 urine samples from dogs (n = 163) and cats (n = 200) collected via cystocentesis, catheter, endoscopy, or punctation of a ureteral bypass system were analyzed. The results were compared to routine microbiologic culture and AST. Using the manufacturer's thresholds for bacteriuria, we observed a sensitivity of 87.1% (95% confidence interval [CI] 70.2-96.4), specificity of 81.7% (95% CI 73.6-88.1), positive predictive value (PPV) of 55.1% (CI 40.2-69.3), and negative predictive value (NPV) of 96.1% (95% CI 90.3-99.0) for UTIs of cats. For dogs, we observed a sensitivity of 87.1% (95% CI 70.2-96.4), specificity of 87.7% (95% CI 78.5-93.9), PPV of 73.0% (95% CI 55.9-86.2), and NPV of 94.7% (95% CI 86.9-98.5). The AST results of the PA-100 were concordant with the AST on plates in 90% of samples. The device has potential as a POC analyzer in the veterinary field, but a high proportion of false-positive bacteriuria results occurred. About 12% of samples yielded no results due to technical errors. Adjustments to the antibiotics used in the cartridges are required for veterinary medicine.IMPORTANCECurrently available point-of-care (POC) tests for the detection of bacteriuria in cats and dogs show several limitations, and antimicrobial susceptibility testing (AST) is not provided by most of these tests. These POC tests generally necessitate incubation for more than 16 h. The Sysmex PA-100 AST System (PA-100), which is designed as a POC device to detect bacteriuria and perform AST-testing within 45 min in urine samples of female patients suffering from cystitis, was recently tested for the first time in a clinical setting in human medicine. Since timely results to detect bacteriuria and to guide antibiotic use are just as important in companion animals as they are in humans, this study aimed to evaluate the applicability of the PA-100 for veterinary use, testing urine samples from dogs and cats with clinical signs of cystitis. This technology may support faster urinalysis in veterinary patients. However, its current applicability in veterinary diagnostics is limited.