Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 18 de 18
Filter
1.
J Can Assoc Gastroenterol ; 5(1): 32-38, 2022 Feb.
Article in English | MEDLINE | ID: mdl-35118225

ABSTRACT

BACKGROUND: Choosing Wisely Canada (CWC) recommends not to perform gastroscopy for dyspepsia in otherwise healthy adults less than 55 years of age (2014). The aim of this study was to evaluate the use of gastroscopy in a young, healthy population with uncomplicated dyspepsia. METHODS: A retrospective review of gastroscopies completed during 3-month periods in 2015, 2016, and 2017 identified all patients undergoing gastroscopy for the primary indication of dyspepsia. Low-risk patients for dyspepsia were defined as adults, aged 18 to 54 years without alarm symptoms, comorbidities and/or abnormal imaging findings or laboratory values. Gastroscopy and pathology reports were reviewed to identify clinically actionable findings. Clinical outcomes were followed to December 31, 2018 including gastroenterology referrals, emergency room visitation and hospitalization. RESULTS: Among 1358 patients having a gastroscopy for dyspepsia, 480 (35%) were low-risk patients. Sixteen patients 3.3% (16/480) had a clinically actionable result found on gastroscopy or biopsy. No malignant lesions were detected. Low-risk patients were followed up for an average of 2.75 years, 8% (39/480) visited the emergency department (ED), 1% (3/480) of patients were admitted to hospital and 12% (59/480) of patients were re-referred for a dyspepsia-related concern. INTERPRETATION: A high rate of low yield, high cost, invasive endoscopic investigations were performed in this population of otherwise healthy patients under age 55 years. These data suggest limited uptake of current recommendations against the routine use of gastroscopy to investigate dyspepsia.

3.
Clin Gastroenterol Hepatol ; 15(1): 79-85.e3, 2017 01.
Article in English | MEDLINE | ID: mdl-27404964

ABSTRACT

BACKGROUND & AIMS: The efficacy of colorectal cancer (CRC) screening is dependent on participation and subsequent adherence to surveillance. The internet increasingly is used for health information and is important to support decision making. We evaluated the accuracy, quality, and readability of online information on CRC screening and surveillance. METHODS: A Website Accuracy Score and Polyp Score were developed, which awarded points for various aspects of CRC screening and surveillance. Websites also were evaluated using validated internet quality instruments (Global Quality Score, LIDA, and DISCERN), and reading scores. Two raters independently assessed the top 30 websites appearing on Google.com. Portals, duplicates, and news articles were excluded. RESULTS: Twenty websites were included. The mean website accuracy score was 26 of 44 (range, 9-41). Websites with the highest scores were www.cancer.org, www.bowelcanceraustralia.org, and www.uptodate.com. The median polyp score was 3 of 10. The median global quality score was 3 of 5 (range, 2-5). The median overall LIDA score was 74% and the median DISCERN score was 45, both indicating moderate quality. The mean Flesch-Kincaid grade level was 11th grade, rating the websites as difficult to read, 30% had a reading level acceptable for the general public (Flesch Reading Ease > 60). There was no correlation between the Google rank and the website accuracy score (rs = -0.31; P = .18). CONCLUSIONS: There is marked variation in quality and readability of websites on CRC screening. Most websites do not address polyp surveillance. The poor correlation between quality and Google ranking suggests that screenees will miss out on high-quality websites using standard search strategies.


Subject(s)
Colorectal Neoplasms/diagnosis , Health Education/methods , Health Services Research , Internet , Mass Screening/statistics & numerical data , Humans
4.
Can J Gastroenterol ; 27(1): 33-8, 2013 Jan.
Article in English | MEDLINE | ID: mdl-23378981

ABSTRACT

BACKGROUND: Adherence to surveillance colonoscopy guidelines is important to prevent colorectal cancer (CRC) and unnecessary workload. OBJECTIVE: To evaluate how well Canadian gastroenterologists adhere to colonoscopy surveillance guidelines after adenoma removal or treatment for CRC. METHODS: Patients with a history of adenomas or CRC who had surveillance performed between October 2008 and October 2010 were retrospectively included. Time intervals between index colonoscopy and surveillance were compared with the 2008 guideline recommendations of the American Gastroenterological Association and regarded as appropriate when the surveillance interval was within six months of the recommended time interval. RESULTS: A total of 265 patients were included (52% men; mean age 58 years). Among patients with a normal index colonoscopy (n=110), 42% received surveillance on time, 38% too early (median difference = 1.2 years too early) and 20% too late (median difference = 1.0 year too late). Among patients with nonadvanced adenomas at index (n=96), 25% underwent surveillance on time, 61% too early (median difference = 1.85) and 14% too late (median difference = 1.1). Among patients with advanced neoplasia at index (n=59), 29% underwent surveillance on time, 34% too early (median difference = 1.86) and 37% later than recommended (median difference = 1.61). No significant difference in adenoma detection rates was observed when too early surveillance versus appropriate surveillance (34% versus 33%; P=0.92) and too late surveillance versus appropriate surveillance (21% versus 33%; P=0.11) were compared. CONCLUSION: Only a minority of surveillance colonoscopies were performed according to guideline recommendations. Deviation from the guidelines did not improve the adenoma detection rate. Interventions aimed at improving adherence to surveillance guidelines are needed.


Subject(s)
Colonic Polyps/diagnosis , Colonoscopy/methods , Colorectal Neoplasms/diagnosis , Practice Guidelines as Topic , Adenoma/diagnosis , Adenoma/pathology , Adenoma/surgery , Aged , Canada , Colonic Polyps/pathology , Colonic Polyps/surgery , Colonoscopy/standards , Colorectal Neoplasms/prevention & control , Female , Gastroenterology/standards , Guideline Adherence , Humans , Male , Middle Aged , Retrospective Studies , Time Factors
5.
J Cardiovasc Pharmacol ; 61(3): 250-7, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23188121

ABSTRACT

Although low-dose acetylsalicylic acid (ASA) is recommended for prevention of cardiovascular events in at-risk patients, its long-term use can be associated with the risk of peptic ulcer and upper gastrointestinal (GI) symptoms that may impact treatment compliance. This prespecified secondary analysis of the OBERON study (NCT00441727) determined the efficacy of esomeprazole for prevention/resolution of low-dose ASA-associated upper GI symptoms. A post hoc analysis of predictors of symptom prevention/resolution was also conducted. Helicobacter pylori-negative patients taking low-dose ASA (75-325 mg) for cardiovascular protection who had ≥1 upper GI risk factor were eligible. The patients were randomized to once-daily esomeprazole 40 mg, 20 mg, or placebo, for 26 weeks; 2303 patients (mean age 67.6 years; 36% aged >70 years) were evaluable for upper GI symptoms. The proportion of patients with dyspeptic or reflux symptoms (self-reported Reflux Disease Questionnaire) was significantly lower (P < 0.0001) in those treated with esomeprazole versus in those treated with placebo. Treatment with esomeprazole (P < 0.0001), age >70 years (P < 0.01), and the absence of upper GI symptoms at baseline (P < 0.0001) were all factors associated with prevention/resolution of upper GI symptoms. Together, these analyses demonstrate that esomeprazole is effective in preventing and resolving patient-reported upper GI symptoms in low-dose ASA users at increased GI risk.


Subject(s)
Anti-Ulcer Agents/therapeutic use , Aspirin/adverse effects , Cardiovascular Diseases/prevention & control , Esomeprazole/therapeutic use , Gastrointestinal Diseases/prevention & control , Platelet Aggregation Inhibitors/adverse effects , Upper Gastrointestinal Tract/drug effects , Age Factors , Aged , Anti-Ulcer Agents/administration & dosage , Aspirin/administration & dosage , Aspirin/therapeutic use , Dose-Response Relationship, Drug , Double-Blind Method , Dyspepsia/chemically induced , Dyspepsia/epidemiology , Dyspepsia/physiopathology , Dyspepsia/prevention & control , Esomeprazole/administration & dosage , Female , Gastroesophageal Reflux/chemically induced , Gastroesophageal Reflux/epidemiology , Gastroesophageal Reflux/physiopathology , Gastroesophageal Reflux/prevention & control , Gastrointestinal Diseases/chemically induced , Gastrointestinal Diseases/epidemiology , Gastrointestinal Diseases/physiopathology , Humans , Male , Middle Aged , Platelet Aggregation Inhibitors/administration & dosage , Platelet Aggregation Inhibitors/therapeutic use , Risk Factors , Secondary Prevention , Self Report , Upper Gastrointestinal Tract/physiopathology
6.
Can J Gastroenterol ; 26(2): 79-84, 2012 Feb.
Article in English | MEDLINE | ID: mdl-22312606

ABSTRACT

INTRODUCTION: Due to the increasing demand for colonoscopy, adherence to postpolypectomy surveillance guidelines is important. Suboptimal compliance can lead to unnecessary risks and ineffective use of resources. OBJECTIVE: To determine the awareness of and adherence to postpolypectomy surveillance guidelines among members of the Canadian Association of Gastroenterology (CAG). METHODS: A survey describing 14 clinical cases was mailed to all physician members (n=411) of the CAG. Respondents were required to recommend a surveillance interval and a reason for his or her choice. RESULTS: A total of 150 colonoscopists (37%) completed the survey. Adherence to the guidelines varied from 23% to 96% per clinical scenario (median 63%). Recommended surveillance intervals were too short in 0% to 60% of the different cases (median 8%). The recommended interval was most often (60%) too short for a patient with one tubular adenoma with high-grade dysplasia. Surveillance intervals were too long in 4% to 75% of the cases (median 9%). The recommended interval was most often too long in a patient with a villous adenoma 15 mm in size and removed piecemeal (75%). Most often, recommendations were reported to be based on guidelines (median 74%; range 31% to 94%). However, in nine of 14 cases, more than 10% (median 18%; range 12% to 38%) of the respondents stated that their recommendation was based on guidelines, but did not provide the appropriate surveillance interval. CONCLUSIONS: Compliance to colonoscopy surveillance guidelines is suboptimal and reflects both overuse and underuse. The results show that awareness about the content of guidelines needs to be raised and strategies implemented to increase adherence.


Subject(s)
Colonic Polyps/pathology , Colonic Polyps/surgery , Colonoscopy/standards , Guideline Adherence , Population Surveillance , Postoperative Care/standards , Practice Patterns, Physicians' , Precancerous Conditions/pathology , Adult , Canada , Female , Gastroenterology/standards , Health Care Surveys , Health Knowledge, Attitudes, Practice , Humans , Male , Middle Aged , Population Surveillance/methods , Practice Guidelines as Topic , Surveys and Questionnaires
7.
J Clin Gastroenterol ; 43(2): 118-22, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18719513

ABSTRACT

BACKGROUND: The Rome criteria have been introduced to create order in the heterogeneity of functional dyspepsia. The applicability of these symptom-based classification systems remains controversial. GOAL: To evaluate the successive Rome criteria for functional dyspepsia in a large pool of patients with endoscopically verified functional dyspepsia. STUDY: Patients referred to a secondary care district hospital were asked to fill out a questionnaire on gastrointestinal symptoms 2 weeks before upper gastrointestinal endoscopy. Patients were classified according to the Rome I, II, and III criteria for functional dyspepsia. RESULTS: Nine hundred and twelve (70%) patients had no organic disorder explaining their symptoms. According to the Rome I, II, and III criteria, 371 (41%), 735 (81%), and 551 (60%) of these patients had functional dyspepsia, respectively. Twenty-five percent of patients had functional dyspepsia according to all 3 Rome criteria, whereas 15% was not classifiable at all. Forty-four percent and 42% of the patients, respectively, had epigastric pain syndrome and postprandial distress syndrome according to the Rome III criteria; however, 26% of all patients met both criteria and 40% was not classified at all. CONCLUSIONS: The symptom-based Rome classification of functional dyspepsia does not lead to an easily applicable and consistent system that is useful in clinical practice or scientific research.


Subject(s)
Dyspepsia/classification , Dyspepsia/physiopathology , Gastrointestinal Diseases/complications , Gastrointestinal Tract/pathology , Severity of Illness Index , Adult , Aged , Dyspepsia/diagnosis , Dyspepsia/epidemiology , Endoscopy, Gastrointestinal , Female , Gastrointestinal Diseases/classification , Gastrointestinal Diseases/diagnosis , Health Surveys , Humans , Male , Middle Aged , Surveys and Questionnaires
8.
JAMA ; 300(15): 1793-805, 2008 Oct 15.
Article in English | MEDLINE | ID: mdl-18854541

ABSTRACT

CONTEXT: Many individuals experience lower gastrointestinal tract symptoms, most commonly attributable to functional conditions. These individuals are frequently diagnosed with irritable bowel syndrome (IBS) based on their symptoms; however, some may require additional testing or referral to specialists before this diagnosis is made. OBJECTIVE: To systematically review the literature of the accuracy of individual symptoms and combinations of findings in diagnosing IBS. DATA SOURCES: Search of MEDLINE and EMBASE (up to June 2008) for prospective studies reporting on unselected cohorts of adult patients with lower gastrointestinal tract symptoms recorded before investigation. STUDY SELECTION: Studies prospectively evaluating accuracy of individual symptoms or combinations of findings compared with results from investigations of the lower gastrointestinal tract. DATA EXTRACTION: Two authors independently assessed studies and extracted data to estimate likelihood ratios (LRs) of individual symptoms and combinations of findings in diagnosing IBS. RESULTS: Ten studies evaluating 2355 patients were identified, with a summary prevalence of IBS following investigation of 57%. Individual symptom items yielded positive LRs from 1.2 (95% confidence interval [CI], 0.93-1.6) for passage of mucus per rectum to 2.1 (95% CI, 1.4-3.0) for looser stools at onset of abdominal pain and negative LRs from 0.29 (95% CI, 0.12-0.72) for no lower abdominal pain to 0.88 (95% CI, 0.72-1.1) for no passage of mucus per rectum in diagnosing IBS. The Manning criteria had a summary positive LR of 2.9 (95% CI, 1.3-6.4) and a summary negative LR of 0.29 (95% CI, 0.12-0.71). The Rome I criteria had a positive LR of 4.8 (95% CI, 3.6-6.5) and a negative LR of 0.34 (95% CI, 0.29-0.41). The Kruis scoring system provided a summary positive LR of 8.6 (95% CI, 2.9-26.0) and a summary negative LR of 0.26 (95% CI, 0.17-0.41). The Rome II and III criteria have not been studied. CONCLUSIONS: Individual symptoms have limited accuracy for diagnosing IBS in patients referred with lower gastrointestinal tract symptoms. The accuracy of the Manning criteria and Kruis scoring system were only modest. Despite strong advocacy for use of the Rome criteria, only the Rome I classification has been validated. Future research should concentrate on validating existing diagnostic criteria or developing more accurate ways of predicting a diagnosis of IBS without the need for investigation of the lower gastrointestinal tract.


Subject(s)
Irritable Bowel Syndrome/diagnosis , Abdominal Pain/etiology , Diagnosis, Differential , Diarrhea/etiology , Humans , Irritable Bowel Syndrome/physiopathology , Physical Examination
10.
J Clin Microbiol ; 44(11): 4136-41, 2006 Nov.
Article in English | MEDLINE | ID: mdl-16988016

ABSTRACT

A leading hypothesis for the role of bacteria in inflammatory bowel diseases is that an imbalance in normal gut flora is a prerequisite for inflammation. Testing this hypothesis requires comparisons between the microbiota compositions of ulcerative colitis and Crohn's disease patients and those of healthy individuals. In this study, we obtained biopsy samples from patients with Crohn's disease and ulcerative colitis and from healthy controls. Bacterial DNA was extracted from the tissue samples, amplified using universal bacterial 16S rRNA gene primers, and cloned into a plasmid vector. Insert-containing colonies were picked for high-throughput sequencing, and sequence data were analyzed, yielding species-level phylogenetic data. The clone libraries yielded 3,305 sequenced clones, representing 151 operational taxonomical units. There was no significant difference between floras from inflamed and healthy tissues from within the same individual. Proteobacteria were significantly (P = 0.0007) increased in Crohn's disease patients, as were Bacteroidetes (P < 0.0001), while Clostridia were decreased in that group (P < 0.0001) in comparison with the healthy and ulcerative colitis groups, which displayed no significant differences. Thus, the bacterial flora composition of Crohn's patients appears to be significantly altered from that of healthy controls, unlike that of ulcerative colitis patients. Imbalance in flora in Crohn's disease is probably not sufficient to cause inflammation, since microbiotas from inflamed and noninflamed tissues were of similar compositions within the same individual.


Subject(s)
Bacteria/isolation & purification , Colitis, Ulcerative/microbiology , Crohn Disease/microbiology , Intestines/microbiology , Adult , Aged , Archaea/isolation & purification , Bacteroides/isolation & purification , Clostridium/isolation & purification , Female , Humans , Male , Middle Aged , Proteobacteria/isolation & purification
11.
Can J Gastroenterol ; 20(6): 411-23, 2006 Jun.
Article in English | MEDLINE | ID: mdl-16779459

ABSTRACT

BACKGROUND: Delays in access to health care in Canada have been reported, but standardized systems to manage and monitor wait lists and wait times, and benchmarks for appropriate wait times, are lacking. The objective of the present consensus was to develop evidence- and expertise-based recommendations for medically appropriate maximal wait times for consultation and procedures by a digestive disease specialist. METHODS: A steering committee drafted statements defining maximal wait times for specialist consultation and procedures based on the most common reasons for referral of adult patients to a digestive disease specialist. Statements were circulated in advance to a multidisciplinary group of 25 participants for comments and voting. At the consensus meeting, relevant data and the results of voting were presented and discussed; these formed the basis of the final wording and voting of statements. RESULTS: Twenty-four statements were produced regarding maximal medically appropriate wait times for specialist consultation and procedures based on presenting signs and symptoms of referred patients. Statements covered the areas of gastrointestinal bleeding; cancer confirmation and screening and surveillance of colon cancer and colonic polyps; liver, biliary and pancreatic disorders; dysphagia and dyspepsia; abdominal pain and bowel dysfunction; and suspected inflammatory bowel disease. Maximal wait times could be stratified into four possible acuity categories of 24 h, two weeks, two months and six months. FUTURE DIRECTIONS: Comparison of these benchmarks with actual wait times will identify limitations in access to digestive heath care in Canada. These recommendations should be considered targets for future health care improvements and are not clinical practice guidelines.


Subject(s)
Consensus , Delivery of Health Care/standards , Gastrointestinal Diseases/therapy , Waiting Lists , Canada , Humans , Time Factors
12.
Gastroenterology ; 130(5): 1538-51, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16678567

ABSTRACT

This document addresses the design of trials to assess the efficacy of new treatments for functional gastrointestinal disorders (FGID), emphasizing trials in irritable bowel syndrome and dyspepsia, because most research has been undertaken in these conditions. The double-blind, randomized, placebo-controlled, parallel group trial remains the preferred design. Randomized withdrawal designs, although encouraged by the European Agency for the Evaluation of Medicinal Products, have the same potential disadvantages as a crossover design, including carryover effects, unmasking (unblinding), and overestimation of the potential benefit for clinical practice. Innovative trial designs that evaluate intermittent (on demand) treatment are likely to become more common in the future. Investigators should include as broad a spectrum of patients as possible and should report recruitment strategies, inclusion/exclusion criteria, and attrition data. The primary analysis should be based on the proportion of patients in each treatment arm who satisfy an a priori treatment responder definition, or a prespecified clinically meaningful change in a patient-reported symptom improvement measure. Such measures of improvement are psychometrically validated subjective global assessments or a change from baseline in a validated symptom severity questionnaire. It is unethical to change the responder definition after a trial begins. Data analysis should address all patients enrolled, using an intention-to-treat principle. Reporting of results should follow the Consolidated Standards for Reporting Trials guidelines and include an analysis of harms data and secondary outcome measures to support or explain the primary outcome. Trials should be registered in a public location, prior to initiation, and should be published even if the results are negative or inconclusive.


Subject(s)
Clinical Trials as Topic , Gastrointestinal Diseases/therapy , Research Design , Clinical Trials as Topic/ethics , Humans
13.
Am J Gastroenterol ; 100(7): 1477-88, 2005 Jul.
Article in English | MEDLINE | ID: mdl-15984968

ABSTRACT

BACKGROUND: The management of Helicobacter pylori negative patients with dyspepsia in primary care has not been studied in placebo-controlled studies. METHODS: H. pylori negative patients with dyspepsia symptoms of at least moderate severity (> or =4 on a seven-point Likert scale) were recruited from 35 centers. Patients were randomized to a 4-wk treatment of omeprazole 20 mg od, ranitidine 150 mg bid, cisapride 20 mg bid, or placebo, followed by on-demand therapy for an additional 5 months. Treatment success was defined as no or minimal symptoms (score < or = 2 out of 7), and was assessed after 4 wk and at 6 months. RESULTS: Five hundred and twelve patients were randomized and included in the intention-to-treat (ITT) analysis. At 4 wk, success rates (95% CI) were: omeprazole 51% (69/135; 43-60%), ranitidine 36% (50/139, 28-44%), cisapride 31% (32/105, 22-39%), and placebo 23% (31/133, 16-31%). Omeprazole was significantly better than all other treatments (p < 0.05). The proportion of patients who were responders at 4 wk and at 6 months was significantly greater for those receiving omeprazole 31% (42/135, 23-39%) compared with cisapride 13% (14/105, 7-20%), and placebo 14% (18/133, 8-20%) (p= 0.001), but not ranitidine 21% (29/139, 14-27%) (p= 0.053). The mean number of on-demand study tablets consumed and rescue antacid used was comparable across groups. Economic analysis showed a trade-off between superior efficacy and increased cost between omeprazole and ranitidine. CONCLUSION: Treatment with omeprazole provides superior symptom relief compared to ranitidine, cisapride, and placebo in the treatment of H. pylori negative primary care dyspepsia patients.


Subject(s)
Cisapride/therapeutic use , Dyspepsia/drug therapy , Gastrointestinal Agents/therapeutic use , Omeprazole/therapeutic use , Ranitidine/therapeutic use , Adult , Aged , Cisapride/adverse effects , Cisapride/economics , Cost-Benefit Analysis , Drug Costs , Dyspepsia/physiopathology , Female , Gastrointestinal Agents/adverse effects , Gastrointestinal Agents/economics , Humans , Male , Middle Aged , Omeprazole/adverse effects , Omeprazole/economics , Quality of Life , Ranitidine/adverse effects , Ranitidine/economics , Time Factors , Treatment Outcome
14.
Can J Gastroenterol ; 19(5): 285-303, 2005 May.
Article in English | MEDLINE | ID: mdl-15915244

ABSTRACT

The present paper is an update to and extension of the previous systematic review on the primary care management of patients with uninvestigated dyspepsia (UD). The original publication of the clinical management tool focused on the initial four- to eight-week assessment of UD. This update is based on new data from systematic reviews and clinical trials relevant to UD. There is now direct clinical evidence supporting a test-and-treat approach in patients with nondominant heartburn dyspepsia symptoms, and head-to-head comparisons show that use of a proton pump inhibitor is superior to the use of H2-receptor antagonists (H2RAs) in the initial treatment of Helicobacter pylori-negative dyspepsia patients. Cisapride is no longer available as a treatment option and evidence for other prokinetic agents is lacking. In patients with long-standing heartburn-dominant (ie, gastroesophageal reflux disease) and nonheartburn-dominant dyspepsia, a once-in-a-lifetime endoscopy is recommended. Endoscopy should also be considered in patients with new-onset dyspepsia that develops after the age of 50 years. Conventional nonsteroidal anti-inflammatory drugs, acetylsalicylic acid and cyclooxygenase-2-selective inhibitors can all cause dyspepsia. If their use cannot be discontinued, cotherapy with either a proton pump inhibitor, misoprostol or high-dose H2RAs is recommended, although the evidence is based on ulcer data and not dyspepsia data. In patients with nonheartburn-dominant dyspepsia, noninvasive testing for H pylori should be performed and treatment given if positive. When starting nonsteroidal anti-inflammatory drugs for a prolonged course, testing and treatment with H2RAs are advised if patients have a history of previous ulcers or ulcer bleeding.


Subject(s)
Algorithms , Dyspepsia/drug therapy , Age Factors , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Barrett Esophagus/diagnosis , Barrett Esophagus/epidemiology , Cyclooxygenase Inhibitors/therapeutic use , Dyspepsia/microbiology , Endoscopy, Gastrointestinal , Esophageal Neoplasms/epidemiology , Gastroesophageal Reflux/complications , Helicobacter Infections/therapy , Helicobacter pylori , Humans , Primary Health Care , Risk Factors , Treatment Outcome
16.
Infect Immun ; 71(5): 2534-41, 2003 May.
Article in English | MEDLINE | ID: mdl-12704125

ABSTRACT

The identification of genes associated with colonization and persistence of Helicobacter pylori in the gastric mucosa has been limited by the lack of robust animal models that support infection by strains whose genomes have been completely sequenced. Here we report that an interleukin-12 (IL-12)-deficient mouse (IL-12(-/-) p40 subunit knockout in C57BL/6 mouse) is permissive for infection by a motile variant (KE88-3887) of The Institute For Genomic Research-sequenced strain (KE26695) of H. pylori. The IL-12-deficient mouse was also more permissive for colonization by the mouse-colonizing Sydney 1 strain of H. pylori than were wild-type C57BL/6 mice. Differences in colonization efficiency were demonstrated by mouse challenge with SS1 strains containing loss-of-function mutations in two genes (hspR and hrcA), whose products negatively regulate several heat shock genes. At 5 weeks postinfection, double-knockout mutants (SS1 hspR hrcA) efficiently colonized IL-12-deficient mice (5 of 5 animals compared to 4 of 10 for C57BL6 mice) and bacterial counts were higher in stomachs of IL-12-deficient mice (10(6) versus 10(5) CFU/g of stomach, respectively). IL-12-deficient mice were efficiently colonized by KE88-3887 (29 of 30), but not by nonmotile KE26695, and bacterial numbers (10(4) to 10(5) CFU/g of stomach) were unchanged over an 8-week period postinfection. In contrast, C57BL/6 mice were inefficiently colonized by KE88-3887 (8 of 20 animals with bacterial loads at the limit of detection, approximately 10(3) CFU/g), and infection did not persist much beyond 5 weeks. Cytokine responses (tumor necrosis factor alpha and gamma interferon), pathology, and antral-predominant infection were indistinguishable between IL-12-deficient and C57BL/6 mice. The increased permissiveness of the IL-12-deficient mouse for infection with H. pylori should facilitate whole-genome-based strategies to study genes associated with virulence and immune modulation.


Subject(s)
Bacterial Proteins , Gastric Mucosa/microbiology , Helicobacter Infections/etiology , Helicobacter pylori/physiology , Interleukin-12/physiology , Animals , DNA-Binding Proteins , Female , Heat-Shock Proteins/physiology , Mice , Mice, Inbred C57BL , Mice, Knockout , Models, Animal , Repressor Proteins/physiology
SELECTION OF CITATIONS
SEARCH DETAIL
...