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Query: UMLS:C0034186 (pyelonephritis)
 6,144 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects on the urinary tract after inoculation of Ureaplasma urealyticum into the rat bladder were evaluated and compared to that seen after Mycoplasma hominis, Escherichia coli and Proteus mirabilis inoculation. The inoculation of the urease-producing organisms P. mirabilis and U. urealyticum were associated with the formation of struvite bladder stones and predominantly hyperplastic lesions of the bladder. The P. mirabilis inoculated rats also displayed marked pyelonephritis. A similar but much less pronounced reaction also occurred in the kidneys of some of the U. urealyticum inoculated rats. P. mirabilis could frequently be recultured. In contrast, this was not possible with U. urealyticum, but the organism was detected by scanning electron microscopy 2 weeks after the inoculation. Inoculation of M. hominis was associated with a few mild lesions of the bladder, but inflammatory lesions were not present in the kidneys. The study confirms the potential of Ureaplasma to form struvite stones in rat urinary tract. It also demonstrates that it can induce inflammatory changes in both bladder and kidney of rats without concomitant stone formation.
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PMID:Morphological lesions of the rat urinary tract induced by inoculation of mycoplasmas and other urinary tract pathogens. 267 69

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 serotypically diverse bacterial isolates at greater than or equal to 10(5) CFU/ml. A total of 86% of specimens contained at least one urease-positive species, and 46% of 3,939 gram-negative bacilli were urease positive. For investigation of genetic relatedness of urease determinants, whole-cell DNA from 50 urease-positive isolates each of Providencia stuartii, Providencia rettgeri, P. mirabilis, Proteus vulgaris, and Morganella morganii were hybridized with a urease gene probe derived from within the urease operon of Providencia stuartii BE2467. The percentage of strains hybridizing with the gene probe was 98 for Providencia stuartii, 100 for Providencia rettgeri, 70 for P. mirabilis, 2 for M. morganii, and 0 for P. vulgaris. Electrophoretic mobilities of ureases from representative isolates revealed nine different patterns among the five species. The urease gene probe hybridized with fragments of HindIII-digested chromosomal DNA from all isolates except M. morganii. Fragment sizes differed between species. Molecular sizes of the enzymes, determined by Sephacryl S-300 chromatography, were found to be 280 kilodaltons (kDa) (P. mirabilis), 323 to 337 kDa (Providencia stuartii, Providencia rettgeri, P. mirabilis, P. vulgaris), 620 kDa (providencia rettgeri), and greater than 700 kDa (M. morganii, Providencia rettgeri). Kms ranged from 0.7 mM urea for M. morganii to 60 mM urea for a P. mirabilis isolate. In general, P. mirabilis ureases demonstrated lower affinities for substrate but hydrolyzed urea at rates 6- to 25-fold faster than did enzymes from other species, which may explain the frequent association of this species with stone formation.
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PMID:Genetic and biochemical diversity of ureases of Proteus, Providencia, and Morganella species isolated from urinary tract infection. 362 98

Magnesium ammonium phosphate calculi developed in the urinary bladders and urethras of four of five offspring of Miniature Schnauzer parents with recurrent struvite urolithiasis. Calculi were detected by radiograhy when the dogs were 12 to 15 months old. Males and females were affected. A significant number of urease-producing staphylococci were identified in the urine of three of four dogs before urolith formation, and in one dog after urolith formation. The dogs were evaluated until they were 26 months old. Serum concentrations of calcium, phosphorus, and magnesium were inside usual limits throughout the study. Abnormalities that might predispose to urinary tract infection were not identified by radiography or necropsy studies. In one dog, bladder calculi recurred after surgical removal of multiple cystoliths. In another, urethral obstruction and acute generalized pyelonephritis induced a lethal uremic crisis. Gross and microscopic lesions, detected after necropsy of all dogs with uroliths, were typical of bacterial infection.
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PMID:Struvite urolithiasis in a litter of miniature Schnauzer dogs. 740 90

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

Proteus mirabilis urease catalyzes the hydrolysis of urea, initiating the formation of urinary stones. The enzyme is critical for kidney colonization and the development of acute pyelonephritis. Urease is induced by urea and is not controlled by the nitrogen regulatory system (ntr) or catabolite repression. Purified whole-cell RNA from induced and uninduced cultures of P. mirabilis and Escherichia coli harboring cloned urease sequences was probed with a 4.2-kb BglI fragment from within the urease operon. Autoradiographs of slot blots demonstrated 4.2- and 5.8-fold increases, respectively, in urease-specific RNA upon induction with urea. Structural and accessory genes necessary for urease activity, ureD, A, B, C, E, and F, were previously cloned and sequenced (B. D. Jones and H. L. T. Mobley, J. Bacteriol. 171:6414-6422, 1989). A 1.2-kb EcoRV-BamHI restriction fragment upstream of these sequences confers inducibility upon the operon in trans. Nucleotide sequencing of this fragment revealed a single open reading frame of 882 nucleotides, designated ureR, which is transcribed in the direction opposite that of the urease structural and accessory genes and encodes a 293-amino-acid polypeptide predicted to be 33,415 Da in size. Autoradiographs of sodium dodecyl sulfate-polyacrylamide gels of [35S]methionine-labeled polypeptides obtained by in vitro transcription-translation of the PCR fragments carrying only ureR yielded a single band with an apparent molecular size of 32 kDa. Fragments carrying an in-frame deletion within ureR synthesized a truncated product. The predicted UreR amino acid sequence contains a potential helix-turn-helix motif and an associated AraC family signature and is similar to that predicted for a number of DNA-binding proteins, including E. coli proteins that regulate acid phosphatase synthesis (AppY), porin synthesis (EnvY), and rhamnose utilization (RhaR). These data suggest that UreR governs the inducibility of P. mirabilis urease.
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PMID:Proteus mirabilis urease: transcriptional regulation by UreR. 767 44

The urinary tract is among the most common sites of bacterial infection and E. coli is by far the most common infecting agent. In patients with urinary catheters in place or structural abnormalities of the urinary tract, Proteus mirabilis is also a frequent isolate. To study virulence of these bacterial species, we have isolated the genes that encode putative virulence factors, constructed specific mutations within these genes, introduced the mutation back into the wild type strain by allelic exchange, and analyzed these mutants for virulence in appropriate in vitro and in vivo models. Specific virulence markers have been identified for strains that cause urinary tract infection. For E. coli, these include P fimbriae, S fimbriae, hemolysin, aerobactin, serum resistance, and a small group of O-serotypes. Redundant virulence factors must be present in these organisms as mutation of the most clearly identified epidemiological marker, P fimbriae, does not result in attenuation of a virulent strain. For P. mirabilis, urease appears to contribute most significantly to virulence. Fimbriae play a significant but more subtle role in colonization. Hemolysin, although potently cytotoxic to renal cells in vitro, does not appear to contribute significantly to the pathogenesis of ascending urinary tract infection. We can conclude that the pathogenesis of urinary tract infection and acute pyelonephritis caused by uropathogenic E. coli and P. mirabilis are multifactorial, as mutation of single genes rarely causes significant attenuation of virulence.
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PMID:Virulence determinants of uropathogenic Escherichia coli and Proteus mirabilis. 786 62

Proteus mirabilis, a significant cause of bacteriuria and acute pyelonephritis in humans, produces urease. This high-molecular-weight, multimeric, cytoplasmic enzyme hydrolyzes urea to ammonia and carbon dioxide. To assess the role of urease in colonization, urolithiasis, and acute pyelonephritis in an animal model of ascending urinary tract infection, we compared a uropathogenic strain of P. mirabilis with its isogenic urease-negative mutant, containing an insertion mutation within ureC, the gene encoding the large subunit of the enzyme. Mice challenged transurethrally with the parent strain developed significant bacteriuria and urinary stones. The urease-negative mutant had a 50% infective dose of 2.7 x 10(9) CFU, a value more than 1,000-fold greater than that of the parent strain (2.2 x 10(6) CFU). The urease-positive parent strain reached significantly higher concentrations and persisted significantly longer in the bladder and kidney than did the mutant. Indeed, in the kidney, the parent strain increased in concentration while the mutant concentration fell so that, by 1 week, the parent strain concentration was 10(6) times that of the mutant. Similarly, the urease-positive parent produced significantly more severe renal pathology than the mutant. The initial abnormalities were in and around the pelvis and consisted of acute inflammation and epithelial necrosis. By 1 week, pyelitis was more severe, crystals were seen in the pelvis, and acute pyelonephritis, with acute interstitial inflammation, tubular epithelial cell necrosis, and in some cases abscesses, had developed. By 2 weeks, more animals had renal abscesses and radial bands of fibrosis. We conclude that the urease of P. mirabilis is a critical virulence determinant for colonization, urolithiasis, and severe acute pyelonephritis.
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PMID:Contribution of Proteus mirabilis urease to persistence, urolithiasis, and acute pyelonephritis in a mouse model of ascending urinary tract infection. 851 76

Bacteria isolated from the urine of 142 patients with chronic pyelonephritis (CPN) were examined for pathogenic properties of the strains (bacteriuria, hemolytic, proteolytic properties, urease, adhesive activity, antibiotic resistance, the ability to inactivate bactericidal activity of the serum) to control the effect of the treatment: antibiotics combined with plasmapheresis or antibiotics combined with laser radiation (intravascular, transcutaneous, or both). Combined application of intravascular and transcutaneous laser irradiation in multimodality treatment reduces the number of highly pathogenic strains as well as antibactericidal activity of the urine strains. It also promotes normalization of bacteriuria level. Plasmapheresis is inferior to laser radiation but ranks the second in efficacy of action on urinary microflora. Thus, use of efferent methods, especially transcutaneous plus intravascular laser radiation, plasmapheresis, in combined treatment of pyelonephritis decreases pathogenicity of urine strains and normalizes bacteriuria.
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PMID:[Effects of plasmapheresis and lasers on the state of urinary microflora in chronic pyelonephritis]. 972 16

The gram-negative enteric bacterium Proteus mirabilis is a frequent cause of urinary tract infections in individuals with long-term indwelling catheters or with complicated urinary tracts (e.g., due to spinal cord injury or anatomic abnormality). P. mirabilis bacteriuria may lead to acute pyelonephritis, fever, and bacteremia. Most notoriously, this pathogen uses urease to catalyze the formation of kidney and bladder stones or to encrust or obstruct indwelling urinary catheters. Here we report the complete genome sequence of P. mirabilis HI4320, a representative strain cultured in our laboratory from the urine of a nursing home patient with a long-term (> or =30 days) indwelling urinary catheter. The genome is 4.063 Mb long and has a G+C content of 38.88%. There is a single plasmid consisting of 36,289 nucleotides. Annotation of the genome identified 3,685 coding sequences and seven rRNA loci. Analysis of the sequence confirmed the presence of previously identified virulence determinants, as well as a contiguous 54-kb flagellar regulon and 17 types of fimbriae. Genes encoding a potential type III secretion system were identified on a low-G+C-content genomic island containing 24 intact genes that appear to encode all components necessary to assemble a type III secretion system needle complex. In addition, the P. mirabilis HI4320 genome possesses four tandem copies of the zapE metalloprotease gene, genes encoding six putative autotransporters, an extension of the atf fimbrial operon to six genes, including an mrpJ homolog, and genes encoding at least five iron uptake mechanisms, two potential type IV secretion systems, and 16 two-component regulators.
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PMID:Complete genome sequence of uropathogenic Proteus mirabilis, a master of both adherence and motility. 1837 54

Corynebacterium urealyticum, formerly known as coryneform CDC group D2, was first recognized to be involved in human infections 30 years ago. It is a slow-growing, lipophilic, asaccharolytic and usually multidrug-resistant organism with potent urease activity. Its cell wall peptidoglycan, menaquinone, mycolic and cellular fatty acid composition is consistent with that of the genus Corynebacterium. DNA-DNA hybridization studies and 16S rDNA sequencing analysis have been used to determine the degree of relatedness of C. urealyticum to other corynebacterial species. The genome of the type strain consists of a circular chromosome with a size of 2 369 219 bp and a mean G + C content of 64.2%, and analysis of its genome explains the bacterium's lifestyle. C. urealyticum is a common skin colonizer of hospitalized elderly individuals who are receiving broad-spectrum antibiotics. It is an opportunistic pathogen causing mainly acute cystitis, pyelonephritis, encrusted cystitis, and encrusted pyelitis. More infrequently, it causes other infections, but mainly in patients with urological diseases. Infections are more common in males than in females, and treatment requires administration of antibiotics active against the organism in vitro, mainly glycopeptides, as well as surgical intervention, the latter mostly in cases of chronic infection. Mortality directly associated with infection by this organism is not frequent, but encrusted pyelitis in kidney-recipient patients may cause graft loss. The outcome of infection by this organism is reasonably good if the microbiological diagnosis is made and patients are treated appropriately.
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PMID:Microbiological and clinical features of Corynebacterium urealyticum: urinary tract stones and genomics as the Rosetta Stone. 1855 35


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