Neisseria flavescens: A Urease-Expressing Potential Pathogen Isolated from Gastritis Patients.

Parasitic pathogens, such as H. pylori (Helicobacter pylori), are considered as primary elements for causing stomach infection and leading to chronic gastritis or ulcers. Here, an unreported urease- and oxidase-producing Neisseria flavescens-like bacteria was isolated from the gastroscopic biopsies of 14C-UBT-positive gastritis patients. The isolate expressed the activity of urease, which is a pathogenic factor and considered as a reliable marker for diagnosis of H. pylori infection. However, the isolate didn't express the key functional genes of H. pylori including vacA and hpaA, and also the morphological feature of isolate was significantly different with H. pylori. Eventually, the 16S rDNA of isolate was sequenced and its sequence shared about 99.8% similarity with the N. flavescens standard strains, but about 20.8% similarity with the H. pylori. Further study of antibiotics-resistance revealed the N. flavescens isolate is high resistant to metronidazole, but highly sensitive to ampicillin sodium. To summarize, a urease-expressing N. flavescens strain was isolated and identified from Chinese gastritis patients; the encouraging results provides an important reference for the further study of its pathogenicity and the reasonable diagnosis and use of antibiotics clinically.