Development of an easy-to-use urease kit for detecting in canine gastric mucosa.

Background And Aim: is an important pathogen in humans and animals involved in chronic gastritis, leading to the development of gastric cancer. Urease produced by is an enzyme that promotes bacterial colonization and can be used clinically as a biomarker of infection as part of a rapid urease test (RUT). A test with high specificity (95-100%) would be more convenient and faster than histopathology, bacterial culture, and polymerase chain reaction (PCR). The aim of this study was to develop a simple, cheap, and fast kit for detecting infection in the gastric mucosa of canines, which can be used in clinical practice for diagnosing infection with this bacterium.

Materials And Methods: The RUT assays developed were prepared using 1% agar, 1% sodium phosphate monobasic, and 1% urea followed by the addition of 3% methyl red indicator. The cutoff value of sensitivity of the RUT assay was established using the urease of ATCC 43504 and color change was monitored for 24 h. Comparisons of the sensitivity to ATCC 43504 were made between the developed RUT assays and the Hp Fast™ commercial kit. Then, the limit of detection for ATCC 43504 number was analyzed by the SYBR Green real-time PCR assay to measure the copy number of the C gene. Gastric biopsy samples from the antrum, body, and fundus of the stomach were collected from eight canines presenting with vomiting and gastroenteritis. Analyses were performed on fresh samples using the developed RUT assays and the Hp Fast™ commercial kit, which were read within 24 h; then, the results were confirmed with SYBR Green real-time PCR. The specificity of the RUT assays was tested with a number of different bacteria, including , spp., , , spp., , and spp.; ATCC 43504 was used as a positive control.

Results: The results showed that the developed assays were sensitive to the urease enzyme at 0.1 mg/mL. The lowest detection limit of this assay for ATCC 43504 was found to be 10 copies at 30 min. The sensitivity of detection of in gastric biopsies of canines occurred in a minimum of 30 min. The RUT showed similar results to the Hp Fast™ commercial kit. In the developed RUT, the color change of the test from red to yellow could be clearly distinguished between the color of the positive test and the negative one; however, in the commercial Hp Fast™, it was difficult to observe the gel color changein the negative pH range of 5.8 and the positive pH of 6.5. The developed RUT was specific for and did not detect any of the other tested bacteria. The test kit can also be stored for 6 months at 4°C.

Conclusion: The sensitivity of the developed assays allowed the detection of urease enzyme at a minimum concentration of 0.1 mg/mL. Our RUT could also detect from one in eight canine specimens at a minimum of 10 copies within 30 min. This RUT is specific to as it did not detect any of the other tested bacteria.