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Query: UMLS:C0009319 (colitis)
 19,384 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A Vero cell cytotoxin that produces colonic lesions and subsequent colonic hemorrhage in mice has been purified from a strain of Escherichia coli O157:H7 that causes hemorrhagic colitis in humans. This toxin is different in physicochemical properties from the Shiga-like toxin previously associated with this organism and may be responsible for the unique diffuse mucosal hemorrhage in the colon of individuals with E. coli O157:H7 infections.
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PMID:Colonic hemorrhage produced in mice by a unique vero cell cytotoxin from an Escherichia coli strain that causes hemorrhagic colitis. 355 50

Classical cholera has reappeared in Asia after a 20-year hiatus, reminding us that we still have much to learn about the epidemiology of this disease. The unexpected recovery of V. cholerae from nonendemic estuarine waters suggests that the continued occurrence of clinical cholera may not be entirely dependent on repeated contamination of environmental waters by man. Of critical importance has been the discovery and partial characterization of new enterotoxins produced by V. cholerae and ETEC, a finding that further complicates the already complex problem of fully elucidating the virulence mechanism of these organisms. The recent purification of Shiga toxin is beginning to provide clues as to its structure, function, and possible pathogenic role in EPEC-related hemorrhagic colitis and diarrhea. The conversion of virulent V. cholerae into less virulent strains by genetic engineering provides hope for the ultimate development of safe and effective live oral cholera vaccines. Intestinal Peyer's patches process living and killed enteropathogens differently, and this discovery may afford insights into ways to improve antigen potency. Enterotoxins differ fundamentally in their biochemical effects, and not all of them evoke active electrolyte secretion by altering cyclic-nucleotide levels in mucosal cells. Finally, the mucosal response to a protein toxin may be under some genetic control. The complete proceedings of this conference will be published by KTK Publishers (Tokyo). The next Joint Conference on Cholera has been scheduled for early November 1984 in Nara, Japan.
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PMID:From the National Institute of Allergy and Infectious Diseases. Summary of the 19th United States-Japan Joint Cholera Conference. 637 50

Escherichia coli K-12 acquired the ability to produce a high titer of Shiga-like toxin after lysogenization by either of two different bacteriophages isolated from a highly toxinogenic Escherichia coli O157:H7 strain that causes hemorrhagic colitis. One of these phages and another Shiga-like toxin-converting phage from an Escherichia coli O26 isolate associated with infantile diarrhea were closely related in terms of morphology, virion polypeptides, DNA restriction fragments, lysogenic immunity, and heat stability, although a difference in host range was noted. These phages are currently the best-characterized representatives from a broader family of Shiga-like toxin-converting phages.
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PMID:Shiga-like toxin-converting phages from Escherichia coli strains that cause hemorrhagic colitis or infantile diarrhea. 638 11

The purpose of this study was to assess a simplified method for interstrain differentiation of Escherichia coli O157:H7 and other Shiga-like toxin-producing E. coli (SLTEC) strains. A method based on the use of nucleic acid probes from Shiga-like toxin (SLT) I and II structural genes was used to generate restriction fragment length polymorphism (RFLP) patterns of SLTEC strains, (SLT-RFLP patterns) resulting from digestion of isolated genomic DNA with four different restriction enzymes (BamHI, EcoRI, HindIII, and PvuII) used separately. A total of 165 SLTEC strains from clinical, food, and environmental sources, including O157:H7 isolates from four food-borne outbreaks in Canada and the United States, were analyzed in the study. SLT-RFLP demonstrated that E. coli O157:H7 strains from each food-borne outbreak had the same unique SLT-RFLP pattern. Fifty-two SLT-RFLP types were found among 96 E. coli O157:H7 isolates from sporadic cases of hemorrhagic colitis and hemolytic uremic syndrome in Washington state. The use of the SLT probes proved to be a very powerful method for interstrain differentiation of SLTEC strains. Although the use of each of the enzymes alone did not give enough differentiative power to be used in epidemiological studies, the combination of patterns generated by two restriction enzymes (EcoRI and PvuII, used separately) provided the desired sensitivity for such studies. The results clearly demonstrate the usefulness of the method for studying the molecular epidemiology of E. coli O157:H7. The method is also suitable for establishing an epidemiological database, in terms of both sensitivity and ease of compilation and interpretation of results.
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PMID:Molecular epidemiology of Escherichia coli O157:H7 by restriction fragment length polymorphism using Shiga-like toxin genes. 755 66

To investigate the length of time that Shiga-like toxin-producing Escherichia coli O157 is excreted after the onset of diarrhea, 456 serial stool specimens were obtained from 53 children. E. coli O157 cells were identified by the use of DNA probes followed by agglutination with a specific antiserum. Specimens were collected until three consecutive stool samples (collected within 9 days) were negative for E. coli O157. The median durations of shedding were 13 days (range, 2 to 62 days) in patients with diarrhea or hemorrhagic colitis and 21 days (range, 5 to 124 days) in patients that developed hemolytic uremic syndrome. In 36 (68%) of the patients, only the first culture was O157 positive, and the three cultures that followed were negative. In 7 (13%) of the patients, E. coli O157 cells were shed for more than 32 days after the onset of diarrhea; these long-term shedders were clinically asymptomatic by the end of this period. In 12 patients, one or two serial O157-negative cultures, obtained up to 8 days after a positive culture, were followed by another positive culture. Comparison of the first and last E. coli O157 isolates by pulsed-field gel electrophoresis revealed that in three of the seven long-term shedders, pulsed-field gel electrophoresis types varied. In two cases, a Shiga-like toxin gene was apparently lost during infection. The observation of long-term shedding accompanied by genotypic turnover has epidemiological and diagnostic implications.
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PMID:Long-term shedding and clonal turnover of enterohemorrhagic Escherichia coli O157 in diarrheal diseases. 765 Jan 95

The genetic relationships among 1,300 isolates of Escherichia coli representing 16 serotypes associated with enteric disease, including O157:H7 strains recovered from patients with hemorrhagic colitis and hemolytic uremic syndrome and O26:H11, O55:H6, O55:H7, O111:H2, and O128:H2 strains, many of which were isolated originally from infants with diarrhea, were estimated from allelic variation among 20 enzyme-encoding genes detected by multilocus enzyme electrophoresis. Multiple electrophoretic types were observed among isolates of each serotype, with isolates of the same O serogroup differing on average at 28% of the enzyme loci. Comparisons of the multilocus enzyme profiles revealed that 72% of the isolates belong to 15 major electrophoretic types, each of which corresponds to a bacterial clone with a wide geographic distribution. Genetically, the O157:H7 clone is most closely related to a clone of O55:H7 strains that has long been associated with worldwide outbreaks of infantile diarrhea. We propose that the new pathogen emerged when an O55:H7-like progenitor, already possessing a mechanism for adherence to intestinal cells, acquired secondary virulence factors (Shiga-like cytotoxins and plasmid-encoded adhesins) via horizontal transfer and recombination.
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PMID:Clonal relationships among Escherichia coli strains that cause hemorrhagic colitis and infantile diarrhea. 768 92

E. coli O157:H7 is one of many E. coli organisms that contain genes encoding one or more toxins similar in structure and function to Shiga toxin. E. coli O157:H7 is the most frequently isolated diarrheagenic type of E. coli isolated in North America today; this pathogen can cause serious, even fatal disease. Syndromes caused by E. coli O157:H7 include diarrhea, hemorrhagic colitis, and HUS. Poorly cooked ground beef has been the most frequently implicated vehicle of transmission, but additional vehicles are being identified. Treatment consists of rehydration during hemorrhagic colitis and support of the patient during the multiple systemic complications of HUS. A policy of routine screening for E. coli O157:H7 in clinical microbiology laboratories, without reliance on the physician to request that this organism be sought or the technician to notice blood in the stool, is the most effective way to find cases. Timely and accurate diagnosis can prevent secondary transmission, avert unnecessary and possibly dangerous procedures and/or therapies, and detect continuing outbreaks. SLTEC strains other than E. coli O157:H7 may cause diseases similar to or less severe than those caused by E. coli O157:H7. At present, however, screening for such pathogens in clinical laboratories is too labor-intensive to be practical. Education and legislation should promote safe food-preparation and food-handling practices. Research should be directed at reducing the carriage of E. coli O157:H7 at its bovine source, minimizing the microbial content of food and water, and averting systemic microangiopathic hemolytic anemia after infection with this pathogen.
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PMID:Escherichia coli O157:H7: clinical, diagnostic, and epidemiological aspects of human infection. 1107 78

Shiga-like toxin (SLT)-producing strains of Escherichia coli are known to cause diarrhea, hemorrhagic colitis, and hemolytic-uremic syndrome in humans. The SLTs, particularly those related to type II (SLT-II), are a diverse family of toxins which may have differing in vitro or in vivo properties. To examine the impact of naturally occurring SLT-II sequence variation on the capacity of a given E. coli strain to cause disease, operons encoding four different SLT-II-related toxins, designated SLT-II/O111, SLT-II/OX3a, SLT-II/OX3b, and SLT-II/O48, were cloned in the same orientation in pBluescript. French pressure cell lysates of E. coli DH5 alpha derivatives carrying these plasmids differed markedly in cytotoxicity for Vero cells, with 50% cytotoxic doses ranging from 20 to 328,000/ml. The strains also differed in oral virulence for streptomycin-treated mice, as judged by survival rate and/or median survival time, but virulence did not necessarily correlate with in vitro cytotoxicity. The SLT-II type associated with the lowest oral virulence was SLT-II/O111. Both the overall survival rate and the median survival time of mice challenged with clones producing this toxin were significantly greater than that for mice challenged with a clone producing the closely related SLT-II/OX3a. Experiments with clones carrying chimeric O111/OX3a SLT-II operons indicated that the reduced virulence was associated with an Arg-176-->Gly substitution in the mature A subunit. Clones producing SLT-II/O48 and SLT-II/OX3b had similarly high cytotoxicities for Vero cells, but the latter was more virulent when fed to streptomycin-treated mice, as judged by median survival time. Experiments with clones carrying chimeric O48/OX3b SLT-II operons indicated that the increased virulence was a function of the A subunit of SLT-II/OX3b, which differs from the A subunit of SLT-II/O48 by only two amino acids (Met-4-->Thr and Gly-102-->Asp, respectively). These findings raise the possibility that naturally occurring SLT-II sequence variations may impact directly on the capacity of a given SLT-producing E. coli strain to cause disease.
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PMID:Comparative toxicity and virulence of Escherichia coli clones expressing variant and chimeric Shiga-like toxin type II operons. 779 56

Although population-based studies have shown that children have the highest age-specific incidence of infection with the Shiga-like toxin-producing E. coli (SLTEC), these sporadic case series were not focused specifically on the pediatric age group. We undertook a prospective study to determine the frequency of detection of SLT in an exclusively pediatric population. The study design minimized ascertainment and referral bias by systematically defining the population by the presence of diarrheal symptoms rather than by specific diagnosis, previous submission of stool for culture, or referral to a diarrhea study. All children < 10 years of age hospitalized at a tertiary care pediatric hospital, irrespective of admission diagnosis, were surveyed prospectively at admission and for 2 days thereafter for the presence of defined diarrheal symptoms. From May 1, 1991, to April 30, 1992, 227 patients and 92 age- and season-matched controls were enrolled. Fecal SLT was detected in six (2.6%) patients, three of whom had E. coli O157:H7 organisms were isolated; SLT was not found in any of the controls. SLT was more commonly detected in children 2-10 years of age and in bloody stools. Salmonella was isolated in six (2.6%) cases, Shigella in five (2.2%), and Yersinia in three (1.3%); rotavirus was detected in 46 (20.3%). Two patients with SLT-associated diarrhea had hemolytic uremic syndrome (HUS), and four had hemorrhagic colitis. SLT-associated diarrhea occurred in the summer and fall months in contradistinction to that with rotavirus, which occurred in the winter and spring.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:A prospective study of Shiga-like toxin-associated diarrhea in a pediatric population. 781 34

Shiga-like toxin-producing (SLT) Escherichia coli, particularly those belonging to serogroup O157, are responsible for haemorrhagic colitis, haemolytic uraemic syndrome and some cases of gastro-enteritis. The rapid and reliable diagnosis of all these infections is necessary for correct patient management and for epidemiological reasons, but is rarely possible with present methods. We compared the efficacy of two methods, (i) the culture of faeces in broth that contained mitomycin C followed by enzyme-linked immunosorbent assay (ELISA) for SLTs, and (ii) the culture of faeces on sorbitol MacConkey agar (SMA), in the detection of infections caused by SLT-producing E. coli. SLT-producing E. coli O157 strains were isolated on SMA from 42 of 475 faecal samples, but SLTs were detected by ELISA in culture supernates or lysates of 54 of 475 samples. SLT-producing E. coli strains were isolated subsequently from 11 of 12 ELISA-positive, SMA culture-negative samples by a colony blot technique. In four cases, SLT-producing E. coli of serogroups other than O157 were isolated and in seven cases E. coli O157 was isolated in small numbers. The ELISA is a rapid and sensitive technique for the diagnosis of SLT-producing E. coli infection, especially where low numbers of the organism are present in faeces and when the infection is caused by a serogroup other than O157.
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PMID:Diagnosis of infections with Shiga-like toxin-producing Escherichia coli by use of enzyme-linked immunosorbent assays for Shiga-like toxins on cultured stool samples. 815 73


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