PathoTec strips and spot biochemical tests were evaluated for the ability to biotype Haemophilus influenzae and Haemophilus parainfluenzae. Indole, urease, and ornithine decarboxylase reactions were tested. The results of PathoTec strips compared favorably with those conventional methods; the percent agreements were as follows: indole, 100; urease, 99.5; and ornithine, 97.5. Spot tests were sim...

Bacterial urease, particularly from Proteus mirabilis, has been implicated as a contributing factor in the formation of urinary and kidney stones, obstruction of urinary catheters, and pyelonephritis. Weekly urine specimens (n = 1,135) from 32 patients, residing at two chronic-care facilities, with urinary catheters in place for greater than or equal to 30 days yielded 5,088 phenotypically and ...

Strain SL100 is a gram-positive coccoid isolate prototype with an adhesin specific for gastric mucin and is representative of potentially pathogenic organisms obtained at biopsy from patients with gastric disorders. The urease of this isolate constitutes a significant fraction of the total cell protein, and the outcome of the purification strategy described herein suggests that it is associated...

The heat-labile toxin (LT) of Escherichia coli is a potent mucosal adjuvant that has been used to induce protective immunity against Helicobacter felis and Helicobacter pylori infection in mice. We studied whether recombinant LT or its B subunit (LTB) has adjuvant activity in mice when delivered with H. pylori urease antigen via the parenteral route. Mice were immunized subcutaneously or intrad...

Yersinia enterocolitica produces the enzyme urease which hydrolyses urea, resulting in the production of carbonic acid and ammonia and a net increase in pH. In the presence of urea, urease enhances survival of Y. enterocolitica in the stomach and presumably in other acidic environments the bacteria encounter during the course of infection. In this study we show that Y. enterocolitica urease is ...

Previous studies have demonstrated that Helicobacter pylori (Hp) delays its entry into macrophages and persists inside megasomes, which are poorly acidified and accumulate early endosome autoantigen 1. Herein, we explored the role of Hp urease in bacterial survival in murine peritoneal macrophages and J774 cells. Plasmid-free mutagenesis was used to replace ureA and ureB with chloramphenicol ac...

The urease enzyme of Campylobacter pylori was studied and compared with that of a related spiral-shaped bacterium, St1, isolated from the rodent ileum. Both bacteria possessed constitutive urease enzymes with activities up to 20-70 times that of Proteus vulgaris. This activity was retained on SDS-polyacrylamide gels. A major catalytic subunit of mol. wt 300,000 was located for all (six) strains...

We examined the roles of cell- and antibody-mediated immunity in urease vaccine-induced protection against Helicobacter pylori infection. Normal and knockout mice deficient in major histocompatibility complex (MHC) class I, MHC class II, or B cell responses were mucosally immunized with urease plus Escherichia coli heat-labile enterotoxin (LT), or parenterally immunized with urease plus aluminu...

Proteus mirabilis, a cause of complicated urinary tract infection, produces urease, an essential virulence factor for this species. UreR, a member of the AraC/XylS family of transcriptional regulators, positively activates expression of the ure gene cluster in the presence of urea. To specifically evaluate the contribution of UreR to urease activity and virulence in the urinary tract, a ureR mu...

The urease enzymes of Helicobacter pylori, H. mustelae, H. felis, and H. nemestrinae have been purified to homogeneity by affinity chromatography and characterized. The native urease enzymes of the four organisms were found to be almost identical, with a pI of 6.1 and molecular masses of 480 to 500 kDa, as determined by electrophoretic mobility in nondenaturing polyacrylamide gels. Transmission...