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

Gale, Glen R. (Veterans Administration Hospital, Durham, N.C.). Urease activity and antibiotic sensitivity of bacteria. J. Bacteriol. 91:499-506. 1966.-An investigation was made of the responses of certain urease-positive bacteria to various antibacterial drugs in the presence of highly specific urease inhibitors, in a test of the hypothesis proposed by other workers that inhibition of bacterial urease enhances the sensitivity of the cells to antimicrobial agents. Urease inhibitors employed were seven hydroxamic acids (HA). Six of the seven HA reduced the sensitivity of nine Proteus strains to ampicillin and methenamine mandelate. Two HA increased the sensitivity to colistin, and six HA increased the sensitivity to kanamycin. Investigation of the mechanism of action of the synergistic effect between kanamycin and HA led to the tentative conclusion that potentiation was mediated through an initial alteration of cell permeability by the aminoglycoside antibiotic which permitted accumulation of each of the six HA into the cell, at which point each interacted with pyridoxal phosphate. The single HA which failed to yield synergism with kanamycin failed to interact with pyridoxal phosphate in a nonenzymatic system; the other six HA produced alterations of the normal ultraviolet absorption spectrum of the coenzyme.
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PMID:Urease activity and antibiotic sensitivity of bacteria. 517 5

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

The number of strains of Proteus studied was 413, and these were obtained from all clinical materials with the exception of fecal specimens. Lactose was fermented by 37 strains (P. inconstans, 29%; P. rettgeri, 16%; P. mirabilis, 4.2%; P. morganii, 3.6%; and P. vulgaris, 0%) of which 33 were from the genitourinary system. These 33 strains constituted 12.7% of the 260 strains isolated from this source. Biochemically, P. mirabilis was the least variable, and P. rettgeri was the most variable of the five species of Proteus tested. P. inconstans and P. rettgeri resembled each other more closely than any of the other species of Proteus. Comparison of results obtained in the Memphis area with those found in other locations showed that biochemical characteristics varied most with the substances citrate, salicin, xylose, trehalose, and mannitol. In contrast to earlier reports from Israel and England, none of the strains of P. inconstans in the present study was able to attack urea. All five species of Proteus tested (by the disc method) were highly susceptible to methenamine mandelate. P. mirabilis, P. morganii, and P. vulgaris were also highly susceptible to nitrofurantoin. All strains of P. mirabilis were susceptible to ampicillin. P. inconstans was the most resistant species of Proteus. Of the other 356 urease-positive strains tested, 79% were susceptible to chloramphenicol, whereas only 3.8% of the 56 urease-negative strains (P. inconstans) were susceptible. When tested with streptomycin, 61% of urease-positive strains were susceptible and 1.8% of the urease-negative strains were susceptible. Of 36 lactose-positive strains, 33.8% were susceptible to chloramphenicol, whereas 72.8% of all lactose-negative strains were susceptible. Again, of the lactose-positive strains, 17% were susceptible to streptomycin, whereas 56.3% of all lactose-negative strains were susceptible.
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PMID:Metabolic variations of Proteus in the Memphis area and other geographical areas. 566 11

Urease of Proteus rettgeri is an inducible enzyme synthesized specifically in the presence of urea; urea analogues did not act as inducers. Once initiated, the biosynthesis of the enzyme proceeded as a constant fraction of the total protein formed. The rate of urease formation was affected by the carbon source used. In comparison with glycerol, glucose inhibited enzyme synthesis. The addition of ammonium ions to the inducing medium also decreased the rate of urease biosynthesis, and when ammonium ions were present urease activity and urea transport across the cell membrane were inhibited. A kinetic analysis of urease inhibition by ammonium ions, by use of a partially purified preparation of urease, showed that it was a competitive inhibition.
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PMID:Mechanisms of regulation of urease biosynthesis in Proteus rettgeri. 603 8

Measuring the specific enzyme activity in cells of Proteus rettgeri it was shown that urease formation is controlled by repression through ammonia. Derepressed synthesis of the enzyme, as initiated by the absence of ammonia, required an external nitrogen source, which may not only be urea, but also nitrate, glutamate or nutrient broth. In contradiction to earlier reports the observations indicated that urea is not required for the synthesis of this enzyme, and that, therefore, urease is not an inducible enzyme in this microorganism.
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PMID:Regulation by repression of urease biosynthesis in Proteus rettgeri. 612 49

Some properties which may contribute to the pathogenicity of Proteus mirabilis were compared in urinary isolates and in strains provided from soil and from culture collection. Clinical isolates revealed the higher expression of all the features examined in this report: swarming growth, haemagglutination, adherence to human uroepithelial cells, urease activity and haemolytic activity. Noteworthy is the higher mean value of adherence to the uroepithelial cells in clinical strains. Three P. mirabilis urinary isolates were detected which produce an as yet unreported filterable haemolysin. However, the loss of this ability within a few months seems to suggest the temporary presence of a plasmid rapidly eliminated by the Proteus strains.
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PMID:Some biological features of Proteus bacilli. 1. Comparison of Proteus mirabilis strains provided from various sources. 620 1

Three combined media ensuring the determination of 8 characteristics typical of bacteria belonging to the group Proteus-Providencia (tryptophane deamination, urease activity, production of hydrogen sulfite and indol, fermentation of mannitol, maltose, adonitol and inositol) are presented.
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PMID:[Combined media for the simplified and rapid identification of bacteria of the Proteus-Providencia group]. 634 Mar 84

The metabolic activities of faecal and urinary strains of Proteus morgani and P. mirabilis were compared. Regardless of origin, the generation time of P. morgani strains in urine was approximately twice as long as that of the P. mirabilis strains. Urease synthesis was constitutive in P. morgani strains but required induction with urea in the P. mirabilis strains. In the presence of urea, the P. mirabilis strains liberated ammonia more rapidly and produced alkaline conditions more quickly than P. morgani strains, although they synthesized much less urease. These characteristics may place P. morgani strains at a disadvantage in comparison with P. mirabilis strains in their ability to cause urinary tract infections.
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PMID:Proteus morgani is less frequently associated with urinary tract infections than Proteus mirabilis--an explanation. 634 89

The bacterial colonization of urethra and urine was studied over long periods in 16 hospitalized women with long-term indwelling bladder catheter. The cultured flora was polymicrobic and, except for Proteus mirabilis and Escherichia coli, rapidly changing. The colonization patterns showed marked inter-species variations. P. mirabilis was the species most commonly found, and in the urethra it was significantly more persistent than the other species. Unlike the other species, P. mirabilis was rarely found in urine without concomitant urethral growth. Prophylactic measures aimed to reduce the risk of permanent colonization by this pathogen, which is rendered particularly harmful by its urease production, should therefore be directed towards the urethra and the periurethral area.
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PMID:Bacterial colonization of the lower urinary tract in women with long-term indwelling urethral catheter. 636 78


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