Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gram-nagative organisms were tested with commercially available reagentimpregnated strips (PATHO-TEC). Of the 291 strains, all were tested by using seven paper tests and their conventional counterparts. Excellent correlation was obtained with the oxidase, phenylalanine-deaminase, and Voges-Proskauer tests. Indole tests made on liquid medium cultures also gave complete correlation, but some false-negative results with indole-positive Proteus strains were obtained when growth from solid medium was tested by the strip method. Paper strip urease tests were positive within 2 hr with all Klebsiella and some Serratia, Herellea, and Citrobacter strains as well as with Proteus strains. Approximately 15% of citrate strip test results differed from those of the conventional tests, and reproducibility was poor on retest. The lysine decarboxylase strip test showed a number of discrepancies and posed problems of interpretation and readability. Paper reagent strip methods are simple and convenient and merit further development to increase the specificity of those which depend on pH change up to that achieved with the Voges-Proskauer, oxidase, phenylalanine, and indole methods.
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PMID:Comparative study of the efficacy of seven paper-reagent strips and conventional biochemical tests in identifying gram-negative organisms. 490 7

A 10-minute test, utilizing a urease paper-reagent strip (PATHO-TEC), for differentiating Klebsiella and Enterobacter species is described. By using a heavy suspension of organisms and 50 C temperature for incubation, 93% of Klebsiella strains (186/200) were positive and 95% of Enterobacter strains (190/200) were negative with this testing system. The rapid nature of the test (10 min), the facility with which it can be carried out, and the ease with which the strips can be stored and handled may make this a useful aid for the clinical microbiologist.
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PMID:Ten-minute test for differentiating between Klebsiella and Enterobacter isolates. 490 52

A rapid urea-phenylalanine medium was effective for the identification of Proteus and, with one exception, Providencia. Most Klebsiella and a few Enterobacter were urease-positive with this method.
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PMID:Rapid test for urease and phenylalanine deaminase production. 555 89

We investigated the regulation of genes concerned with nitrogen metabolism by oxygen in the facultative anaerobe Klebsiella pneumoniae. We found oxygen to be required for the expression of the hut operons; the effect of O2 on the glutamine synthetase and urease was less pronounced than on the hut operons. Glutamine synthetase was transiently repressed during the transition from an aerobic to an anaerobic environment. Regulation of hut by O2 suppressed the effect of nitrogen limitation on the expression of these genes.
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PMID:Regulation of Klebsiella pneumoniae hut operons by oxygen. 610 51

We have shown that the low histidase activity found in anaerobic, nitrogen-limited cultures of Klebsiella pneumoniae is due to repression of the right-hand hut operon. In addition, we have examined the effects of NO3- on the aerobic and anaerobic expression of catabolite- and NH4+-repressible enzymes in this organism. NO3- permitted anaerobic growth of K. pneumoniae in minimal medium containing histidine as the sole carbon source, and histidase and succinate dehydrogenase were derepressed during anaerobic growth in histidine/NO3- medium. Use of sucrose rather than histidine as the carbon source reversed the effects of NO3- and repressed histidase and succinate dehydrogenase activities. Anaerobic growth in sucrose/NO3- medium also uncoupled the expression of urease and glutamine synthetase.
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PMID:Effects of anaerobiosis and nitrate on the expression of succinate dehydrogenase and enzymes associated with nitrogen metabolism in Klebsiella pneumoniae. 612 18

100 cases of urolithiasis in children treated in Pediatric Clinic of National Research Institute of Mother and Child in the period of 1976-1979 were analized . In 93 children the cause of urolithiasis was established. The most of them (31%) are cases of infection induced urinary stones. Among other reasons of urolithiasis the most common are: metabolic reasons in 26%, probably metabolic reasons in 13%, idiopathic oxalic lithiasis in 17% and others in 6%. At the moment of urolithiasis diagnosis in 94 children bacteriological investigations were done. In 54 cases, i.e. 57,4% infections of the urinary tract were found. 57,8% of boys and 62,2% of girls had urinary tract infections. The most frequent bacteria was urease producting Proteus sp. During 3 years of observation urinary tract infections in 67 children were found. Among bacteria causing the reinfections the most frequent were: Pseudomonas aeruginosa (25,4%), Klebsiella sp. (22,4%), Proteus sp. (19,9%) and E. coli (15%). In 9 cases the bacteriological analysis of removed stones were done. In 2 cases bacteria causing the infection were isolated from the stones, since they were not present in urine any more.
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PMID:[Urinary tract infections and urolithiasis]. 642 22

A total of 503 veterinary enteric bacterial pathogens obtained from state veterinary diagnostic laboratories were tested on API 20E strips to determine whether this rapid microidentification system could be utilized for veterinary clinical microbiology. The API 20E strip accurately identified 96% of the veterinary isolates and misidentified 3%. Identifications by the API system and the diagnostic laboratories were in agreement in 85% of the isolates, disagreement on 16% of the isolates, and 1% were not identified by the API strip. Differences in identification occurred primarily in distinguishing between Klebsiella and Enterobacter and between Enterobacter and Escherichia coli. These disagreements were most often due to incorrect identifications by the diagnostic laboratory rather than by the API system. Biotype differences between human and veterinary isolates were compared. Significant differences were noted in several biochemical reactions. The main differences observed for E. coli isolates were in ornithine decarboxylase production and melibiose fermentation. The largest differences for Salmonella occurred in arginine dihydrolase production, citrate utilization, and inositol fermentation, whereas for Klebsiella pneumoniae the main differences were noted in urease production and nitrate reduction. These biotype differences, however, did not affect the accurate identification of organisms on the API strip.
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PMID:Use of the API 20E system to identify veterinary Enterobacteriaceae. 699 12

The Enteric-Tek wheel (Flow Laboratories), consisting of 14 different biochemical parameters for rapidly identifying Enterobacteriaceae, was evaluated and compared with the conventional method for completely identifying 301 enteric cultures, representing 36 species. The Enteric-Tek system correctly identified 264 (97.8%) of the 270 common or typical strains and 26 (83.9%) of the 31 unusual or atypical strains tested, demonstrating an overall identification accuracy rate of 96.3%. There were 80 (26.6%) correctly identified strains requiring additional tests. Of the 11 (3.6%) misidentifications, 5 (3 Klebsiella and 2 Salmonella strains) were correctly identified at the genus level. When 4,228 individual tests in the Enteric-Tek wheel were compared with the conventional tubed media, 96.4% of the tests agreed; urease, citrate, adonitol, and lactose agreed less than 97%. The Enteric-Tek system was found to be reliable and accurate in producing identifications at the genus and species level within 18 to 24 h.
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PMID:Evaluation of the Enteric-Tek system for identifying Enterobacteriaceae. 704 44

The study of 1023 strains, formerly identified as Shigella, has revealed that 67 of these strains belong to Escherichia, Enterobacter, Klebsiella, Providencia, Pseudomonas, Flavobacterium. Such errors are due to the insufficient use of biochemical tests in the process of identification. To improve Shigella identification, after the evaluation of changes in Olkenitsky's medium of trisaccharide agar the tests for urease activity, citrate and acetate assimilation, lysine decarboxylase, mobility at 22 degrees C, sensitivity to Shigella bacteriophage, oxidase are recommended.
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PMID:[Errors in the bacteriologic diagnosis of dysentery and ways of eliminating them]. 726 16

Urease (urea amidohydrolase; EC 3.5.1.5) catalyzes the hydrolysis of urea to yield ammonia and carbamate. The latter compound spontaneously decomposes to yield another molecule of ammonia and carbonic acid. The urease phenotype is widely distributed across the bacterial kingdom, and the gene clusters encoding this enzyme have been cloned from numerous bacterial species. The complete nucleotide sequence, ranging from 5.15 to 6.45 kb, has been determined for five species including Bacillus sp. strain TB-90, Klebsiella aerogenes, Proteus mirabilis, Helicobacter pylori, and Yersinia enterocolitica. Sequences for selected genes have been determined for at least 10 other bacterial species and the jack bean enzyme. Urease synthesis can be nitrogen regulated, urea inducible, or constitutive. The crystal structure of the K. aerogenes enzyme has been determined. When combined with chemical modification studies, biophysical and spectroscopic analyses, site-directed mutagenesis results, and kinetic inhibition experiments, the structure provides important insight into the mechanism of catalysis. Synthesis of active enzyme requires incorporation of both carbon dioxide and nickel ions into the protein. Accessory genes have been shown to be required for activation of urease apoprotein, and roles for the accessory proteins in metallocenter assembly have been proposed. Urease is central to the virulence of P. mirabilis and H. pylori. Urea hydrolysis by P. mirabilis in the urinary tract leads directly to urolithiasis (stone formation) and contributes to the development of acute pyelonephritis. The urease of H. pylori is necessary for colonization of the gastric mucosa in experimental animal models of gastritis and serves as the major antigen and diagnostic marker for gastritis and peptic ulcer disease in humans. In addition, the urease of Y. enterocolitica has been implicated as an arthritogenic factor in the development of infection-induced reactive arthritis. The significant progress in our understanding of the molecular biology of microbial ureases is reviewed.
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PMID:Molecular biology of microbial ureases. 756 14


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