Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Escherichia coli O157:H7 was conclusively identified as a pathogen in 1982 following its association with two food-related outbreaks of an unusual gastrointestinal illness. The organism is now recognized as an important cause of foodborne disease, with outbreaks reported in the U.S.A., Canada, and the United Kingdom. Illness is generally quite severe, and can include three different syndromes, i.e., hemorrhagic colitis, hemolytic uremic syndrome, and thrombotic thrombocytopenic purpura. Most outbreaks have been associated with eating undercooked ground beef or, less frequently, drinking raw milk. Surveys of retail raw meats and poultry revealed E. coli O157:H7 in 1.5 to 3.5% of ground beef, pork, poultry, and lamb. Dairy cattle, especially young animals, have been identified as a reservoir. The organism is typical of most E. coli, but does possess distinguishing characteristics. For example, E. coli O157:H7 does not ferment sorbitol within 24 h, does not possess beta-glucuronidase activity, and does not grow well or at all at 44-45.5 degrees C. The organism has no unusual heat resistance; heating ground beef sufficiently to kill typical strains of salmonellae will also kill E. coli O157:H7. The mechanism of pathogenicity has not been fully elucidated, but clinical isolates produce one or more verotoxins which are believed to be important virulence factors. Little is known about the significance of pre-formed verotoxins in foods. The use of proper hygienic practices in handling foods of animal origin and proper heating of such foods before consumption are important control measures for the prevention of E. coli O157:H7 infections.
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PMID:Escherichia coli O157:H7 and its significance in foods. 185 98

Fecal isolates of Escherichia coli which were collected from human patients in different parts of Germany between 1985 and 1992 were examined for production of verotoxins (VT). Among 2165 isolates 54 (2.5%) verotoxigenic E. coli (VTEC) were found. The 54 VTEC belonged to 13 different serotypes, 46 (85.2%) of these were enterohemorrhagic E. coli (EHEC) types as O157:H7, O157:H-, O145:H-, O111:[H8] and O26:[H11]. Of the 54 VTEC 50 (92.6%) hybridized with one or both of the DNA probes specific for VT1 and VT2. The 4 VTEC strains which were negative for VT1 and VT2 differed from all other VTEC by many phenotypical trains such as serotype, production of alpha-hemolysin and absence of EHEC-plasmid and "attaching and effacing" (eae)-specific DNA sequences. In contrast, VTEC which were positive for VT1, VT2 or both were frequently positive for eae sequences (92.0%), EHEC-plasmids (90.0%) and for production of enterohemolysin (88.0%). With enterohemolysin as an epidemiological marker more VTEC strains (81.5%) could be identified than with others such as the absence of beta-glucuronidase activity (61.1%) or non-fermentation of sorbitol (48.1%). Case reports were available for 42 of the 54 VTEC strains. The clinical presentation of 42 cases with VTEC ranged from uncomplicated diarrhea to severe diseases as hemorrhagic colitis (HC) and hemolytic uremic syndrome (HUS). However, bloody diarrhea, HC and HUS were more associated with the O157 group than with other VTEC groups.
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PMID:Virulence factors and phenotypical traits of verotoxigenic strains of Escherichia coli isolated from human patients in Germany. 820 27

An atypical, Stx2-producing, pathogenic Escherichia coli O157:H(-) strain has been isolated with increasing frequency from hemolytic uremic syndrome patients in Germany. The lack of the H7 antigen coupled with the strain's ability to ferment sorbitol and express beta-glucuronidase have complicated its detection and identification. In this study, we have determined that the loss of motility in these German sorbitol-fermenting (SF) O157 strains is due to a 12-bp in-frame deletion in flhC that is required for transcriptional activation of genes involved in flagellum biosynthesis. Either complementation with a functional flhC or repair of this mutation restored H7 antigen expression and motility. PCR analysis of several nonmotile E. coli O157 strains from various geographical sources confirmed that the 12-bp flhC deletion is found only in the cluster of German SF O157 strains, providing a potentially useful marker by which these atypical strains can be identified. The loss of motility via mutations in the flhDC operon that we observed in the German SF O157 strains is consistent with a similar phenomenon currently observed in a significant subset of other important gram-negative pathogens.
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PMID:A 12-base-pair deletion in the flagellar master control gene flhC causes nonmotility of the pathogenic German sorbitol-fermenting Escherichia coli O157:H- strains. 1506 34

Infections by Shiga toxin-producing Escherichia coli O157:H7 (STEC O157) are the predominant cause of bloody diarrhea and hemolytic uremic syndrome in the United States. In silico comparison of the two complete STEC O157 genomes (Sakai and EDL933) revealed a strikingly high level of sequence identity in orthologous protein-coding genes, limiting the use of nucleotide sequences to study the evolution and epidemiology of this bacterial pathogen. To systematically examine single nucleotide polymorphisms (SNPs) at a genome scale, we designed comparative genome sequencing microarrays and analyzed 1199 chromosomal genes (a total of 1,167,948 bp) and 92,721 bp of the large virulence plasmid (pO157) of eleven outbreak-associated STEC O157 strains. We discovered 906 SNPs in 523 chromosomal genes and observed a high level of DNA polymorphisms among the pO157 plasmids. Based on a uniform rate of synonymous substitution for Escherichia coli and Salmonella enterica (4.7x10(-9) per site per year), we estimate that the most recent common ancestor of the contemporary beta-glucuronidase-negative, non-sorbitolfermenting STEC O157 strains existed ca. 40 thousand years ago. The phylogeny of the STEC O157 strains based on the informative synonymous SNPs was compared to the maximum parsimony trees inferred from pulsed-field gel electrophoresis and multilocus variable numbers of tandem repeats analysis. The topological discrepancies indicate that, in contrast to the synonymous mutations, parts of STEC O157 genomes have evolved through different mechanisms with highly variable divergence rates. The SNP loci reported here will provide useful genetic markers for developing high-throughput methods for fine-resolution genotyping of STEC O157. Functional characterization of nucleotide polymorphisms should shed new insights on the evolution, epidemiology, and pathogenesis of STEC O157 and related pathogens.
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PMID:Probing genomic diversity and evolution of Escherichia coli O157 by single nucleotide polymorphisms. 1660

Sorbitol-fermenting shiga toxin-producing E. coli O157:H- strains have emerged as a cause of human disease in many European and non-European countries. The role of SF VTEC O157:H- in the etiology of pediatric HUS and diarrhea is significant. We characterized the first SF VTEC O157:H- strain isolated from 9 year old patient in Poland. Strain possessed many traits characteristics for SF VTEC O157:H-. It fermented sorbitol after overnight incubation and produced beta-glucuronidase. It possessed the stx2, eae-gamma, EhlyA and sfpA genes and did not harbour plasmid-encoded katP and espP genes. Motility was not expressed but the strain possessed the chromosomal fliC locus for H7 antigen. The spread of SF VTEC O157:H- strains demonstrates the need for appropriate procedures for their microbiological diagnosis in Poland.
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PMID:[Characterization of first sorbitol-fermenting shiga toxin-producing Escherichia coli O157:H- strain isolated in Poland]. 1914 70