Sources of variation of Helicobacter pylori treatment success in adults worldwide: a meta-analysis

Exposure to antibiotics in a United States-Mexico border birth cohort

OBJECTIVE

The goal was to compare the frequency of children's antibiotic intake, emphasizing antibiotics with anti-Helicobacter pylori effects, in El Paso, Texas, and Juarez, Mexico.

METHODS

Hispanic children were enrolled prenatally at mother-child clinics in El Paso, and Juarez, in 1998-2000, to identify determinants of H pylori infection. During follow-up examinations targeted every 6 months from 6 to 84 months of age, caretakers reported medication use during the preceding interval. Courses of any systemic and H pylori-effective antibiotics were compared for US and Mexican children.

RESULTS

Antibiotic data were available for 602 children, from 2938 follow-up visits. Overall antibiotic intake was higher in Juarez, where 84% of children received > or = 1 course during the follow-up period (52% of visits), compared with El Paso, where 76% of children received > or = 1 course (40% of visits). In contrast, the intake of H pylori-effective antibiotics was higher in El Paso, where 65% of children received > or = 1 course during the follow-up period (27% of visits), compared with Juarez, where 44% of children received > or = 1 course (16% of visits). Of H pylori-effective courses, 94% contained amoxicillin and 2% each clarithromycin, metronidazole, and furazolidone; uses were primarily for throat and ear infections, diarrhea, and cold/flu.

CONCLUSIONS

Pediatric antibiotic use was higher in Mexico than on the US side of the border. Apparent misuse of H pylori-effective antibiotics was more frequent in Juarez but also occurred in El Paso. Such misuse of antibiotics may lead to drug resistance and may impair the control of H pylori infection in this region.

Antibiotics taken for other illnesses and spontaneous clearance of Helicobacter pylori infection in children

PURPOSE

Factors that determine persistence of untreated Helicobacter pylori (H. pylori) infection in childhood are not well understood. We estimated risk differences for the effect of incidental antibiotic exposure on the probability of a detected clearance at the next test after an initial detected H. pylori infection.

METHODS

The Pasitos Cohort Study (1998-2005) investigated predictors of H. pylori infection in children from El Paso, Texas, and Juarez, Mexico. Children were screened for infection at 6-month target intervals from 6 to 84 months of age, using the 13C-urea breath test corrected for body-size-dependent variation in CO2 production. Exposure was defined as courses of any systemic antibiotic (systemic) or those with anti-H. pylori action (HP-effective) reported for the interval between initial detected infection and next test. Binomial regression models included country of residence, mother's education, adequacy of prenatal care, age at infection, and interval between tests.

RESULTS

Of 205 children with a test result and antibiotic data following a detected infection, the number of children who took > or =1 course in the interval between tests was 74 for systemic and 33 for HP-effective. The proportion testing negative at the next test was 66% for 0 courses, 72% for > or =1 systemic course, and 79% for > or =1 HP-effective course. Adjusted risk differences (95%CI) for apparent clearance, comparing > or =1 to 0 courses were 10% (1-20%) for systemic and 11% (0-21%) for HP-effective.

CONCLUSIONS

Incidental antibiotic exposure appears to influence the duration of childhood H. pylori infection but seems to explain only a small portion of spontaneous clearance.

Meta-analysis: four-drug, three-antibiotic, non-bismuth-containing "concomitant therapy" versus triple therapy for Helicobacter pylori eradication

BACKGROUND

Low success rates with triple therapy for Helicobacter pylori infections have prompted search for alternatives. In one, a proton-pump inhibitor (PPI) and amoxicillin was followed by the PPI plus clarithromycin and a nitroimidazole (sequential therapy); in another, these four drugs were given concomitantly (concomitant therapy).

AIM

To compare concomitant therapy with standard triple therapy for H. pylori infection.

METHODS

By searching PubMed, EMBASE, the Cochrane Central Register of Controlled Trials and abstracts of major gastrointestinal meeting, two independent reviewers systemically identified randomized controlled trials (RCT) comparing concomitant quadruple to standard triple therapies as well as studies reporting eradication rates of concomitant quadruple therapy in treatment of H. pylori. Pooled eradication rates and odds ratios (OR) with 95% confidence intervals (CI) were calculated, and univariable metaregression analysis for all extracted variables was conducted.

RESULTS

We identified nine studies (10 treatment arms) including five qualifying RCTs (576 subjects) comparing concomitant (293 subjects, duration 3 to 5 days) and triple therapy (283 subjects, duration 5 to 10 days) and four other studies evaluating concomitant therapy (478 subjects, duration 3 to 7 days). Pooled estimates of the five RCTs showed superiority of concomitant therapy over triple therapy; with intention-to-treat) pooled OR of 2.86 (95% CI: 1.73-4.73) and per-protocol (PP) pooled OR of 3.52 (95% CI: 1.95-6.38). Considering all 10 treatment arms, the ITT eradication rate was 89.7% (95% CI: 86.8-92.1%) and PP was 92.9% (95% CI: 90.2-94.8%).

CONCLUSION

Concomitant therapy appears to be an effective alternative to triple therapy and is less complex than sequential therapy.

Meta-analysis: four-drug, three-antibiotic, non-bismuth-containing "concomitant therapy" versus triple therapy for Helicobacter pylori eradication

BACKGROUND

Low success rates with triple therapy for Helicobacter pylori infections have prompted search for alternatives. In one, a proton-pump inhibitor (PPI) and amoxicillin was followed by the PPI plus clarithromycin and a nitroimidazole (sequential therapy); in another, these four drugs were given concomitantly (concomitant therapy).

AIM

To compare concomitant therapy with standard triple therapy for H. pylori infection.

METHODS

By searching PubMed, EMBASE, the Cochrane Central Register of Controlled Trials and abstracts of major gastrointestinal meeting, two independent reviewers systemically identified randomized controlled trials (RCT) comparing concomitant quadruple to standard triple therapies as well as studies reporting eradication rates of concomitant quadruple therapy in treatment of H. pylori. Pooled eradication rates and odds ratios (OR) with 95% confidence intervals (CI) were calculated, and univariable metaregression analysis for all extracted variables was conducted.

RESULTS

We identified nine studies (10 treatment arms) including five qualifying RCTs (576 subjects) comparing concomitant (293 subjects, duration 3 to 5 days) and triple therapy (283 subjects, duration 5 to 10 days) and four other studies evaluating concomitant therapy (478 subjects, duration 3 to 7 days). Pooled estimates of the five RCTs showed superiority of concomitant therapy over triple therapy; with intention-to-treat) pooled OR of 2.86 (95% CI: 1.73-4.73) and per-protocol (PP) pooled OR of 3.52 (95% CI: 1.95-6.38). Considering all 10 treatment arms, the ITT eradication rate was 89.7% (95% CI: 86.8-92.1%) and PP was 92.9% (95% CI: 90.2-94.8%).

CONCLUSION

Concomitant therapy appears to be an effective alternative to triple therapy and is less complex than sequential therapy.

Meta-analysis: four-drug, three-antibiotic, non-bismuth-containing "concomitant therapy" versus triple therapy for Helicobacter pylori eradication

BACKGROUND

Low success rates with triple therapy for Helicobacter pylori infections have prompted search for alternatives. In one, a proton-pump inhibitor (PPI) and amoxicillin was followed by the PPI plus clarithromycin and a nitroimidazole (sequential therapy); in another, these four drugs were given concomitantly (concomitant therapy).

AIM

To compare concomitant therapy with standard triple therapy for H. pylori infection.

METHODS

By searching PubMed, EMBASE, the Cochrane Central Register of Controlled Trials and abstracts of major gastrointestinal meeting, two independent reviewers systemically identified randomized controlled trials (RCT) comparing concomitant quadruple to standard triple therapies as well as studies reporting eradication rates of concomitant quadruple therapy in treatment of H. pylori. Pooled eradication rates and odds ratios (OR) with 95% confidence intervals (CI) were calculated, and univariable metaregression analysis for all extracted variables was conducted.

RESULTS

We identified nine studies (10 treatment arms) including five qualifying RCTs (576 subjects) comparing concomitant (293 subjects, duration 3 to 5 days) and triple therapy (283 subjects, duration 5 to 10 days) and four other studies evaluating concomitant therapy (478 subjects, duration 3 to 7 days). Pooled estimates of the five RCTs showed superiority of concomitant therapy over triple therapy; with intention-to-treat) pooled OR of 2.86 (95% CI: 1.73-4.73) and per-protocol (PP) pooled OR of 3.52 (95% CI: 1.95-6.38). Considering all 10 treatment arms, the ITT eradication rate was 89.7% (95% CI: 86.8-92.1%) and PP was 92.9% (95% CI: 90.2-94.8%).

CONCLUSION

Concomitant therapy appears to be an effective alternative to triple therapy and is less complex than sequential therapy.

A randomized clinical trial to determine the efficacy of regimens containing clarithromycin, metronidazole, and amoxicillin among histologic subgroups for Helicobacter pylori eradication in a developing country

BACKGROUND

Most treatments deemed effective for Helicobacter pylori eradication in developed countries are less effective in developing countries. Regimens containing clarithromycin, metronidazole, and amoxicillin seem efficacious despite antibiotic resistance, and may be a viable option in developing countries.

MATERIALS AND METHODS

We evaluated the efficacy of a 14-day regimen with 500 mg clarithromycin b.i.d., 500 mg metronidazole t.i.d., and 500 mg amoxicillin t.i.d. (with and without a proton pump inhibitor), and a 10-day regimen containing 500 mg clarithromycin b.i.d., 1 g amoxicillin b.i.d., and 20 mg omeprazole b.i.d. in Pasto, Colombia, using a randomized, single-blind design stratified by presence of atrophic gastritis.

RESULTS

H. pylori was eradicated in 86.8% and 85.3% of the participants randomized to a clarithromycin-metronidazole-amoxicillin and clarithromycin-amoxicillin-omeprazole regimens, respectively (p = .79). Per-protocol analyses indicated greater efficacy for the clarithromycin-metronidazole-amoxicillin regimen (97%) versus the clarithromycin-amoxicillin-omeprazole regimen (86%) (p = .04), particularly for participants with atrophic gastritis (clarithromycin-metronidazole-amoxicillin = 100%, clarithromycin-amoxicillin-omeprazole = 81%; p = .02). Adverse events were mild, but adverse event-related non-compliance was reported more often for regimens containing clarithromycin, metronidazole, and amoxicillin.

CONCLUSIONS

Our results suggest that an eradication rate of > 85% can be achieved with 14-day clarithromycin, metronidazole, and amoxicillin and 10-day clarithromycin, amoxicillin, and omeprazole regimens in Pasto, Colombia. The regimens containing clarithromycin, metronidazole, and amoxicillin appear to be superior to the clarithromycin, amoxicillin, and omeprazole regimen for compliant participants and those with atrophic gastritis. Our findings provide treatment options for a population in a developing country with a high prevalence of H. pylori infections and antibiotic resistance.

H pylori eradication: A randomized prospective study of triple therapy with or without ecabet sodium

AIM: To investigate whether adding ecabet sodium to the standard triple therapy for H pylori infection improve eradication rate.

METHODS: Two hundred and fifty-seven H pylori-infected patients were randomly assigned to standard triple therapy (group A, n = 129) or triple therapy plus ecabet sodium (group B, n = 128). Successful eradication was defined as a negative ¹³C-urea breath test 6-8 wk after completion of treatment.

RESULTS: After completion of therapy, 194/257 patients showed negative ¹³C-urea breath test results. According to intention-to-treat analysis, the infection was eradicated in 93/129 (72.1%) patients in group A and 101/128 (78.9%) in group B (P = 0.204). Per-protocol analysis showed successful eradication in 93/118 (78.8%) patients from group A and 101/114 (88.6%) from group B (P = 0.044). There were no significant differences in the side effects experienced by the patients in the two treatment groups.

CONCLUSION: Our results suggest that the addition of ecabet sodium improves the efficacy of the standard triple therapy for H pylori.

Helicobacter pylori strikes again: gastric mucosa-associated lymphoid tissue (MALT) lymphoma

Infection with Helicobacter pylori is common. Over 50% of the world's population is estimated to be colonized with the bacteria. The association between Helicobacter pylori and gastric mucosa-associated lymphoid tissue (MALT) lymphoma is well documented. Anti-Helicobacter pylori treatment and the successful eradication of the bacteria can potentially cure patients who test positive for the bacteria and who are diagnosed with low-grade gastric MALT lymphoma. The purpose of this article is to review the evidence implicating Helicobacter pylori as a causal pathogen for the development of gastric MALT lymphoma and to determine that anti-Helicobacter pylori therapy is an effective first-line treatment. The clinical presentation, endoscopic findings, diagnosis, staging, treatment, and follow-up of patients with gastric MALT lymphoma who are treated with anti-Helicobacter pylori therapy are also discussed.

External validation of a measurement tool to assess systematic reviews (AMSTAR)

BACKGROUND

Thousands of systematic reviews have been conducted in all areas of health care. However, the methodological quality of these reviews is variable and should routinely be appraised. AMSTAR is a measurement tool to assess systematic reviews.

METHODOLOGY

AMSTAR was used to appraise 42 reviews focusing on therapies to treat gastro-esophageal reflux disease, peptic ulcer disease, and other acid-related diseases. Two assessors applied the AMSTAR to each review. Two other assessors, plus a clinician and/or methodologist applied a global assessment to each review independently.

CONCLUSIONS

The sample of 42 reviews covered a wide range of methodological quality. The overall scores on AMSTAR ranged from 0 to 10 (out of a maximum of 11) with a mean of 4.6 (95% CI: 3.7 to 5.6) and median 4.0 (range 2.0 to 6.0). The inter-observer agreement of the individual items ranged from moderate to almost perfect agreement. Nine items scored a kappa of >0.75 (95% CI: 0.55 to 0.96). The reliability of the total AMSTAR score was excellent: kappa 0.84 (95% CI: 0.67 to 1.00) and Pearson's R 0.96 (95% CI: 0.92 to 0.98). The overall scores for the global assessment ranged from 2 to 7 (out of a maximum score of 7) with a mean of 4.43 (95% CI: 3.6 to 5.3) and median 4.0 (range 2.25 to 5.75). The agreement was lower with a kappa of 0.63 (95% CI: 0.40 to 0.88). Construct validity was shown by AMSTAR convergence with the results of the global assessment: Pearson's R 0.72 (95% CI: 0.53 to 0.84). For the AMSTAR total score, the limits of agreement were -0.19+/-1.38. This translates to a minimum detectable difference between reviews of 0.64 'AMSTAR points'. Further validation of AMSTAR is needed to assess its validity, reliability and perceived utility by appraisers and end users of reviews across a broader range of systematic reviews.

Evolution of Helicobacter pylori therapy from a meta-analytical perspective

Even before the discovery of Helicobacter pylori as their cause, chronic gastritis and peptic ulcer disease were empirically treated with anti-infectious agents. However, it was not until that finding that an antibiotic approach began to be used systematically. The main aim of this article is to review the evolution of H. pylori therapy from a meta-analytical perspective. Initially, antibiotic monotherapy had a minor efficacy on H. pylori. Dual therapy including either bismuth compounds or proton-pump inhibitors (PPI) and one antibiotic also resulted in insufficient cure rates. Bismuth-based triple therapy (the first used) and PPI-based triple therapies (combined with two antibiotics, including amoxicillin, nitroimidazole, or clarithromycin) have been the most widely recommended. PPI-based regimens are superior to H2-antagonist-based ones. The influence of the type of PPI, the dose and the duration of the treatment will be discussed. Among the factors influencing the efficacy of therapy, resistance to clarithromycin and metronidazole are the most important risk factors for eradication failure. Several rescue therapies can be used. Bismuth-based quadruple therapy is effective, but the complexity of the regimen and the associated adverse effects limit the compliance. PPI-based triple therapy with amoxicillin and levofloxacin is at least equally effective and better tolerated.

Nitrofuran-based regimens for the eradication of Helicobacter pylori infection

Several aspects of Helicobacter pylori eradication have been meta-analyzed; however, nitrofuran-based therapies constitute an exception. The aim of this study was the systematic review and meta-analysis of the effect of furazolidone- and nitrofurantoin-based regimens in the eradication of infection. Studies evaluating the effects of nitrofurans on H. pylori were identified from Medline, EMBASE, the Cochrane Controlled Trials Register and congress abstracts. The studies were classified into groups based on first-, second- and third-line regimens. The pooled eradication rates and combined odd ratios of the individual studies were calculated and compared with the published meta-analysis. The factors influencing the efficiency of the regimens were also analyzed. Side-effects of nitrofuran-based regimens were also analyzed. The pooled eradication rate of primary proton pump inhibitor-based regimens containing furazolidone was 76.3% (CI 67.8-84.2). The odds ratio for furazolidone-based regimens versus standard triple therapies was 2.34 (CI 0.76-3.92). Ranitidine bismuth citrate + furazolidone-based triple regimens were equally efficient (83.5%, CI 74.0-93.0, P = 0.06 versus triple therapies). Schedules including a H(2) antagonist + furazolidone + one other antibiotic achieved pooled eradication rates of 79.9% (CI 67.8-89.9, P = 0.04). Bismuth-based triple therapies achieved 84.5% (CI 72.6-93.0, P = 0.002). Primary quadruple regimens containing furazolidone were superior to triple therapies (83.4%, CI 69.7-92.3, P = 0.01). Second-line schedules containing furazolidone obtained eradication rates of 76.1% (CI 66.4-85.0, P = 0.28 versus primary regimens). Third-line 'rescue' therapies were efficient in 65.5% of the cases (CI 56.3-75.5, P = 0.0001). Side-effects of the regimens containing furazolidone were more frequent than in standard therapies (P = 0.02). The combined odds ratio of side-effects for furazolidone-based versus standard therapies was 0.74 (CI 0.32-1.98). The duration of treatment, but not the furazolidone dose, influenced the treatment outcome. Primary triple regimens containing furazolidone are slightly less efficient than the standard primary combinations; primary quadruple regimens were more efficient than triple therapies. Furazolidone is also efficient as a component of second-line or rescue therapies.

One-week versus two-week furazolidone-based quadruple therapy as the first-line treatment for Helicobacter pylori infection in Iran

BACKGROUND AND AIM

Furazolidone-based regimens for the eradication of Helicobacter pylori are low cost and effective although less tolerable. Our aim was to compare the efficacy and compliance of 1-week furazolidone-based quadruple therapy (furazolidone, amoxicillin, bismuth subcitrate, omeprazole; FABO) with 2-week quadruple therapy using the same drugs.

METHODS

One hundred and fifty-six consecutive patients with H. pylori related diseases were enrolled in our study. The patients were randomized into two groups of FABO1 and FABO2 groups receiving, 1 or 2 weeks' quadruple H. pylori eradication therapies, respectively, as follows: furazolidone (200 mg twice daily), amoxicillin (1 g twice daily), bismuth (240 mg twice daily) and omeprazole (20 mg twice daily). The chi(2) test was used to compare the efficacy of the therapies.

RESULTS

The per-protocol eradication rate in FABO1 and FABO2 groups were 56/66 (84.8%) and 57/69 (82.6%), respectively. The intention-to-treat eradication rate was 56/78 (71.8%) in FABO1 group and 57/78 (73.1%) in FABO2 group. There was not any significant statistical difference between two groups. A significant decrease in compliance in FABO2 group was seen.

CONCLUSION

This is an encouraging report showing a therapy with possible success in decreasing the duration of H. pylori infection as well as reaching the eradication rate of 80%.

A meta-analysis of the success rate of Helicobacter pylori therapy in Canada

BACKGROUND AND AIM

Helicobacter pylori treatment success rates have varied. A systematic review of the success rate of anti- H pylori therapy in Canada was performed.

METHODS

All clinical trials containing Canadian data on the success rate of H pylori treatment were identified using MEDLINE searches, through review of references of retrieved studies and by contacting key investigators. Both randomized and open-label trials were included. Treatment effect size was calculated using a variation of Cochran's Q method.

RESULTS

Seventeen papers met the inclusion criteria. Both triple therapies consisting of a proton pump inhibitor (PPI), clarithromycin and either amoxicillin or metronidazole performed well, achieving a success rate of 84% and 82%, respectively. The cure rate of PPI-amoxicillin + metronidazole was 76%. Quadruple therapy consisting of a PPI, bismuth, metronidazole and tetracycline, given for seven to 10 days, achieved a success rate of 87%.

CONCLUSION

Both PPI-based triple therapy and quadruple therapy perform well in Canada for the treatment of H pylori infection.

Meta-analysis: the effect of antibiotic resistance status on the efficacy of triple and quadruple first-line therapies for Helicobacter pylori

BACKGROUND

Information regarding the effects of drug resistance on therapies for Helicobacter pylori is limited.

AIMS

To determine the effect of drug resistance on the efficacy of first-line treatment regimens for H. pylori and identify the most efficacious treatments in the presence of drug resistance.

METHODS

We searched for studies using the keywords: 'Helicobacter pylori','resistance' and 'treatment' or 'therapy'. Multilevel meta-regression models were used to determine the effect of drug resistance on treatment efficacy.

RESULTS

We analysed data from 93 studies with 10,178 participants. For triple therapies, clarithromycin resistance had a greater effect on treatment efficacy than nitroimidazole resistance. Metronidazole resistance reduced efficacy by 26% in triple therapies containing a nitroimidazole, tetracycline and bismuth, while efficacy was reduced by only 14% when a gastric acid inhibitor was added to the regimen. Quadruple therapies containing both clarithromycin and metronidazole were the most efficacious; >80% of H. pylori infections were consistently eradicated with these regimens.

CONCLUSIONS

Drug resistance was a strong predictor of efficacy across triple therapies for the eradication of H. pylori in adults. Resistance to either clarithromycin or metronidazole, but not both simultaneously, may be overcome by using quadruple therapies, especially those containing both clarithromycin and metronidazole.

Meta-analysis: Helicobacter pylori eradication treatment efficacy in children

BACKGROUND

Several meta-analyses assessing the efficacy of anti-Helicobacter pylori treatment in adults have been published but a comparable meta-analysis in children is lacking.

AIMS

To summarize the efficacy of treatments aimed at eradicating H. pylori in children and to identify sources of variation in treatment efficacy across studies.

METHODS

We searched Medline, reference lists from published study reports, and conference proceedings for anti-H. pylori treatment trials in children. Weighted meta-regression models were used to find sources of variation in efficacy.

RESULTS

Eighty studies (127 treatment arms) with 4436 children were included. Overall, methodological quality of these studies was poor with small sample sizes and few randomized-controlled trials. The efficacy of therapies varied across treatment arms, treatment duration, method of post-treatment assessment and geographic location. Among the regimens tested, 2-6 weeks of nitroimidazole and amoxicillin, 1-2 weeks of clarithromycin, amoxicillin and a proton pump inhibitor, and 2 weeks of a macrolide, a nitroimidazole and a proton pump inhibitor or bismuth, amoxicillin and metronidazole were the most efficacious in developed countries.

CONCLUSIONS

Before worldwide treatment recommendations are given for eradication of H. pylori, additional well-designed randomized placebo-controlled paediatric trials are needed, especially in developing countries where both drug resistance and disease burden is high.

Helicobacter pylori and antimicrobial resistance: molecular mechanisms and clinical implications

Helicobacter pylori is an important human pathogen that colonises the stomach of about half of the world's population. The bacterium has now been accepted as the causative agent of several gastroduodenal disorders, ranging from chronic active gastritis and peptic ulcer disease to gastric cancer. The recognition of H pylori as a gastric pathogen has had a substantial effect on gastroenterological practice, since many untreatable gastroduodenal disorders with uncertain cause became curable infectious diseases. Treatment of H pylori infection results in ulcer healing and can reduce the risk of gastric cancer development. Although H pylori is susceptible to many antibiotics in vitro, only a few antibiotics can be used in vivo to cure the infection. The frequent indication for anti-H pylori therapy, together with the limited choice of antibiotics, has resulted in the development of antibiotic resistance in H pylori, which substantially impairs the treatment of H pylori-associated disorders. Antimicrobial resistance in H pylori is widespread, and although the prevalence of antimicrobial resistance shows regional variation per antibiotic, it can be as high as 95%. We focus on the treatment of H pylori infection and on the clinical relevance, mechanisms, and diagnosis of antimicrobial resistance.

Generalizability in two clinical trials of Lyme disease

Objective

To examine the generalizability of two National Institutes of Health (NIH)-funded double-blind randomized placebo-controlled clinical trials in patients with chronic Lyme disease and to determine whether selection factors resulted in the unfavorable outcomes.

Design

Epidemiologic review of the generalizability of two trials conducted by Klempner et al. This paper considers whether the study group was representative of the general chronic Lyme disease population.

Results

In their article in The New England Journal of Medicine, Klempner et al. failed to discuss the limitations of their clinical trials. This epidemiologic review argues that their results are not generalizable to the overall Lyme disease population. The treatment failure reported by the authors may be the result of enrolling patients who remained ill after an average of 4.7 years and an average of 3 previous courses of treatment. The poor outcome cited in these trials may be explained by having selected patients who had undergone delayed treatment or multiple treatments unsuccessfully. These selection factors were not addressed by the studies' authors, nor have they been discussed by reviewers. The trials have been over-interpreted by the NIH and widely publicized in a press release. The results have been extrapolated to other groups of Lyme disease patients by commentators, by a case discussant in an influential medical journal, and by health insurance companies to deny antibiotic treatment.

Conclusion

The Klempner et al. trials are assumed to be internally valid based on a Randomized Control Trial (RCT) design. However, this review argues that the trials have limited generalizability beyond the select group of patients with characteristics like those in the trial. Applying the findings to target populations with characteristics that differ from those included in these trials is inappropriate and may limit options for chronic Lyme disease patients who might benefit from antibiotic treatment.

Prevalence and mechanisms of resistance to fluoroquinolones in Helicobacter pylori strains from patients living in Belgium

BACKGROUND

Because of the increasing resistance of Helicobacter pylori against metronidazole and clarithromycin, alternative regimens including newer fluoroquinolones have been developed. We aimed to assess the prevalence as well as the mechanisms of this resistance in clinical isolates originating from patients living in Belgium.

METHODS

Minimal inhibitory concentration (MIC) values of ciprofloxacin, levofloxacin, and moxifloxacin were determined by Etest method on 488 H. pylori isolates originating from patients who underwent upper gastrointestinal endoscopy at 10 different centers. Resistant strains (MIC values > 1 microg/ml) were evaluated for the presence of point mutations in the quinolone resistance-determining region (QRDR) of the gyrA by amplification and nucleotide sequence.

RESULTS

Eighty-two (16.8%) of the strains were found resistant to all fluoroquinolones and 70 of these were further analyzed. Homogeneous and heterogeneous resistance were observed in 55 (78.6%) and in 15 (21.4%) of the strains, respectively. QRDR sequencing revealed various mutations of the codons corresponding to Asn-87 and Asp-91 in all isolates with homogeneous resistance. However, in 12 of 15 strains displaying heterogenous resistance, mutations were only detected after subcultures of isolated colonies growing within the ellipse inhibition zone of the E-test. Amino acid substitutions in the QRDR of GyrA could not be directly related with the MIC values of the isolates. Fluoroquinolone-resistant mutants were easily selected in vitro at frequencies ranging between 10(-6) and 10(-7). Such selected mutants stably persisted after several serial passage in antibiotic-free agar.

CONCLUSIONS

These results suggest that H. pylori resistance to fluoroquinolones is occurring at a high frequency in the Belgian population and that it is essentially mediated through a variety of point mutations occurring in a few loci of GyrA. As a consequence, we strongly suggest to determine the susceptibility of the infecting isolates to fluoroquinolones before administration of an anti-H. pylori regimen including these agents.

Institutional difference of antibiotic resistance of Helicobacter pylori strains in Korea

GOALS

This study was performed to evaluate whether the prevalence rates of primary antibiotic resistance in Helicobacter pylori isolates could be different between 2 institutions, which are located in the different areas in Korea, and to evaluate the effect of antibiotic resistance on the eradication rate of H. pylori.

STUDY

H. pylori were isolated from gastric mucosal biopsy specimens obtained from 113 Koreans, who did not have any eradication history. The susceptibilities of the H. pylori isolates to amoxicillin, clarithromycin, metronidazole, tetracycline, levofloxacin, and moxifloxacin were examined according to the agar dilution method by 1 technician.

RESULTS

All of these patients were treated with the same regimen, proton pump inhibitor-amoxicillin-clarithromycin triple therapy. There was a statistical difference in resistance to metronidazole, levofloxacin, and moxifloxacin among 6 antibiotics between 2 institutions located in Seoul and Gyeonggi province. The rates of eradication were 94.2% for the clarithromycin and amoxicillin-susceptible strains, and 42.8% for the amoxicillin-susceptible and clarithromycin-resistant strains. In contrast, eradication rate was 100% for the amoxicillin-resistant strains.

CONCLUSIONS

These results show that there is institutional difference of antibiotic resistance of H. pylori, explaining the institutional difference of eradication rate of H. pylori. The resistance to clarithromycin seems to be an important determinant for the eradication by proton pump inhibitor triple therapy but resistance to amoxicillin does not have any effect.

Helicobacter pylori diagnosis and management

H pylori is a global human pathogen and is the major cause of gastritis and the gastritis-associated diseases: gastric ulcer, duodenal ulcer, gastric cancer, and primary gastric B-cell lymphoma (MALToma). Although several reliable diagnostic tests are widely available, the ideal regimen for treating the infection re-mains to be established. The current first-line or legacy triple therapy regimens fail in 20% to 40% of patients. Causes of treatment failure include antibiotic resistance, poor compliance, short (7-10 days) duration of therapy, and drug-related side effects. Fourteen-day triple therapy has an approximately 12% better cure rate than does 7-day therapy; therefore, shorter durations can no longer be recommended. Recent studies confirmed older observations that the success rate of legacy triple regimens (PPI plus two antibiotics) can be improved if the duration is extended to 14 days or if a third antibiotic is given. Sequential therapy (PPI plus amoxicillin followed by a PPI plus clarithromycin plus metronidazole) requires further evaluation although the concept appears very promising and therapy should probably replace the legacy triple therapies. More studies are needed to examine doses, durations, and the need for sequential administration of the drugs, which extends the duration to 14 days. Nonetheless, sequential quadruple therapy probably should replace the legacy triple therapies. Classic quadruple therapy contains bismuth, a PPI, 1500 mg of metronidazole, and 1500 mg of tetracycline. It provides the highest average eradication rates and in many regions should be considered as the initial approach. Confirmation of eradication using noninvasive diagnostic tests, such as a urea breath test or stool antigen assay, is now the standard of care. The diagnosis of latent or symptomatic H pylori like the diagnosis of latent or symptomatic syphilis, always should prompt treatment. Because of decreasing cure rates, new and improved therapies are needed.

Review in depth and meta-analysis of controlled trials on colorectal cancer screening by faecal occult blood test

BACKGROUND

Several randomized studies have shown that colorectal cancer (CRC) screening by faecal occult blood test (FOBT) reduces CRC mortality. These trials have different designs, especially concerning FOBT frequency and duration, as well as the length of follow-up after stopping FOBT campaigns.

AIMS

To review the effectiveness of screening for CRC with FOBT, to consider the reduction in mortality during or after screening or to identify factors associated with a significant mortality reduction.

METHODS

A systematic review of trials of FOBT screening with a meta-analysis of four controlled trials selected for their biennial and population-based design. The main outcome measurements were mortality relative risk (RR) and 95% confidence interval (CI) of biennial FOBT during short (10 years, i.e. five or six rounds) or long-term (six or more rounds) screening periods, as well as after stopping screening and follow-up during 5-7 years. The meta-analysis used the Mantel-Haenszel method with fixed effects when the heterogeneity test was not significant, and used 'intent to screen' results.

RESULTS

Although the quality of the four trials was high, only three were randomized, and one used rehydrated biennial FOBT associated with a high colonoscopy rate (28%). A meta-analysis of mortality results showed that subjects allocated to screening had a reduction of CRC mortality during a 10-year period (RR 0.86; CI 0.79-0.94) although CRC mortality was not decreased during the 5-7 years after the 10-year (six rounds) screening period, nor in the last phase (8-16 years after the onset of screening) of a long-term (16 years or nine rounds) biennial screening. Whatever the design of the period of ongoing FOBT, CRC incidence neither decreased nor increased, although it was reduced for 5-7 years after the 10-year screening period. Neither the design nor the clinical or demographic parameters of these trials were independently associated with CRC mortality reduction.

CONCLUSION

Biennial FOBT decreased CRC mortality by 14% when performed over 10 years, without evidence-based benefit on CRC mortality when performed over a longer period. No independent predictors of CRC mortality reduction have been identified in order to allow a CRC screening programme in any subgroups of subjects at risk.

Rabeprazole containing triple therapy to eradicate Helicobacter pylori infection on the Texas-Mexican border

BACKGROUND

Antibiotic resistance and duration of therapy influence the success of proton-pump inhibitor-containing Helicobacter pylori eradication therapy. Clarithromycin resistance is associated with treatment failure.

AIM

To examine the success of a 7-day rabeprazole-clarithromycin-amoxicillin therapy in the study population.

METHODS

Adults from Ciudad Juarez with H. pylori infections identified by culture or histology received rabeprazole 20 mg, clarithromycin 0.5 g and amoxicillin 1 g, each b.d. for 7 days. Outcome was assessed by 13C-urea breath test carried out 4+ weeks after treatment.

RESULTS

A total of 111 patients were enrolled and evaluated by urea breath test; 102 completed the full 7 days therapy. Two deviated from protocol, and five stopped because of adverse events. The cure rate (intention-to-treat) was 85% (95% CI: 78-91%); the per-protocol cure rate was 85% (95% CI: 78-91%). Side-effects were not serious and only 6.6% of those with adverse events stopped medication. Only three isolates were clarithromycin-resistant and none was cured. Compliance explained most of the successes.

CONCLUSIONS

In the study population a 7-day rabeprazole triple eradication therapy was both effective and well-tolerated. Clarithromycin resistance was uncommon. We observed a slightly better outcome but consistent with results from recent large studies in US populations.

Helicobacter pylori eradication in childhood after failure of initial treatment: advantage of quadruple therapy with nifuratel to furazolidone

BACKGROUND

Failures of Helicobacter pylori eradication in children are common.

AIM

To evaluate the efficacy of amoxicillin, bismuth subcitrate and omeprazole and nifuratel or furazolidone for H. pylori eradication in children who failed initial treatment with a standard triple therapy.

METHODS

Seventy-six consecutive H. pylori-positive paediatric out-patients (aged 12-16 years; mean age 13.7 +/- 1.4) with chronic abdominal complaints who had failed one attempt of eradication of H. pylori using metronidazole-containing triple therapy were enrolled. It was an open prospective study. Patients were randomized to receive a 2-week course of bismuth subcitrate (8 mg/kg/day, q.d.s.), amoxicillin (50 mg/kg/day, q.d.s.), with either nifuratel (15 mg/kg/day, q.d.s.) or furazolidone (10 mg/kg/day, q.d.s.), plus omeprazole (0.5 mg/kg, once daily).

RESULTS

There were 37 patients in the nifuratel group and 39 in the furazolidone group. Helicobacter pylori was eradicated in 33 of 37 (89%; 95% CI: 74.5-96.9; intention-to-treat) in nifuratel group and in 34 of 39 (87%; 95% CI: 72.5-95.7) in furazolidone group, respectively. Frequency of severe side-effects was greater with furazolidone (21%) than with nifuratel (3%; P = 0.0289).

CONCLUSIONS

Nitrofuran-containing therapies consisting of a proton-pump inhibitor, amoxicillin and bismuth citrate plus either nifuratel or furazolidone produced good cure rates even among those who had failed prior therapy. Nifuratel is preferred because of the lower frequency of side-effects.

Meta-analysis: the efficacy, adverse events, and adherence related to first-line anti-Helicobacter pylori quadruple therapies

BACKGROUND

Owing to rising drug-resistant Helicobacter pylori infections, currently recommended proton-pump inhibitor-based triple therapies are losing their efficacy, and regimens efficacious in the presence of drug resistance are needed.

AIMS

To summarize the efficacy, safety and adherence of first-line quadruple H. pylori therapies in adults.

METHODS

Meta-regression models identified factors explaining variation in the efficacy of first-line quadruple therapies from 145 treatment arms. Estimates of average efficacy were calculated within homogeneous groups.

RESULTS

Quadruple therapy containing a gastric acid inhibitor, bismuth, metronidazole and tetracycline was enhanced when omeprazole was included, treatment duration lasted 10-14 days, and when therapy took place in the Netherlands, Hong Kong and Australia. Treatment efficacy decreased as the prevalence of metronidazole resistance increased. Even in areas with a high prevalence of metronidazole resistance, this quadruple regimen eradicated more than 85% of H. pylori infections when it contained omeprazole and was given for 10-14 days. Furthermore, in the presence of clarithromycin resistance, this quadruple regimen eradicated 90-100% of H. pylori infections, while the currently recommended triple therapy containing clarithromycin, amoxicillin and a proton-pump inhibitor eradicated only 25-61% (P < 0.001). Adherence and adverse events for quadruple therapy were similar to currently recommended triple therapies.

CONCLUSIONS

Guidelines should include quadruple therapy with a proton-pump inhibitor, a bismuth compound, metronidazole and tetracycline among recommended first-line anti-H. pylori therapies.

Helicobacter pylori infection in pregnant women from a U.S.-Mexico border population

Helicobacter pylori infection causes chronic digestive diseases that disproportionately affect Hispanics and other immigrant groups in the United States. Information on the epidemiology of H. pylori infection in pregnant women who reside along the U.S.-Mexico border is critical to understanding the dynamics of current H. pylori transmission patterns within families along the border. We describe the epidemiology of H. pylori infection in pregnant women recruited from Women, Infants, and Children (WIC) clinics in El Paso, Texas, and Mexican Social Security Institute maternal-child clinics in Ciudad Juarez, Mexico, from April 1998 to October 2000. We interviewed participants regarding environmental factors and tested their serum for IgG antibodies. We used logistic regression to estimate associations between environmental exposures and the odds of H. pylori prevalence. Definitive serological tests were available from 751 women. Seroprevalence was 74% in Juarez women and 56% in El Paso women. Prevalence increased with age, crowding, poor sanitation, and residence in Mexico, decreased with education, and was not associated with the woman's number of living children. In the U.S.-Mexico border region, women of reproductive age have a high prevalence of H. pylori infection, apparently related to poor socioeconomic conditions.

One-week triple therapy with esomeprazole, clarithromycin and metronidazole provides effective eradication of Helicobacter pylori infection

AIM

To compare the eradication rates of treatment with esomeprazole, metronidazole and clarithromycin (EMC) vs. omeprazole, metronidazole and clarithromycin (OMC), given for 7 days. OMC treatment was followed by 3 weeks of treatment with 20 mg omeprazole alone; the EMC group received placebo.

METHODS

A randomized, double-blind, controlled study was conducted in 36 Canadian centres. Patients had a minimum 3-month history of dyspepsia, with or without a previous history of peptic ulcer disease, and were Helicobacter pylori positive by urea breath test. The eradication of H. pylori was determined by two negative breath tests performed at least 4 and 8 weeks following the completion of treatment.

RESULTS

The intention-to-treat and per protocol populations consisted of 379 and 339 patients, respectively. The success rates of EMC/placebo were 76% (144/190) by intention-to-treat and 80% (138/172) by per protocol analysis; for OMC/omeprazole, the rates were 72% (137/189) and 75% (125/167), respectively. The difference between the two treatment groups was not significant. Treatment was well tolerated.

CONCLUSIONS

A 7-day regimen of esomeprazole, metronidazole and clarithromycin is effective and well tolerated for the eradication of H. pylori infection.

Fluorescence in situ hybridization vs. epsilometer test for detection of clarithromycin-susceptible and clarithromycin-resistant Helicobacter pylori strains in gastric biopsies from children

AIM

To compare the results of culture and epsilometer test with fluorescence in situ hybridization for the detection of Helicobacter pylori and the presence of clarithromycin-susceptible and clarithromycin-resistant strains in antral biopsies from children.

METHODS

Antral biopsies from 149 unselected children were investigated prospectively; 15 had previously received anti-H. pylori therapy. H. pylori status was defined by histology, rapid urease test and 13C-urea breath test. Fluorescence in situ hybridization was applied on fresh tissue with probes specific for the clarithromycin-susceptible wild type and three clarithromycin-resistant mutants. Susceptibility to clarithromycin was tested by epsilometer test in two laboratories.

RESULTS

Culture and fluorescence in situ hybridization gave negative results in all 66 H. pylori-negative children (specificity, 100%). Of 83 infected children, cultures were successful in 75 (90%), epsilometer test in 71 (86%) and fluorescence in situ hybridization in 77 (93%). Eleven children (13%) showed discrepant results between the applied methods, indicating mixed infection. Clarithromycin-resistant isolates were identified in 16 of 73 previously untreated children.

CONCLUSIONS

Primary resistance to clarithromycin is common (22%) in H. pylori isolates from children living in Germany. Fluorescence in situ hybridization is an excellent, fast method for the detection of H. pylori and clarithromycin-resistant mutants in gastric biopsies. Multiple biopsies identify mixed infections, indicating that clarithromycin-resistant and clarithromycin- susceptible strains are not evenly distributed within the stomach.

Emergence of tetracycline resistance in Helicobacter pylori: multiple mutational changes in 16S ribosomal DNA and other genetic loci

Tetracycline is useful in combination therapies against the gastric pathogen Helicobacter pylori. We found 6 tetracycline-resistant (Tet(r)) strains among 159 clinical isolates (from El Salvador, Lithuania, and India) and obtained the following four results: (i) 5 of 6 Tet(r) isolates contained one or two nucleotide substitutions in one part of the primary tetracycline binding site in 16S rRNA (AGA(965-967) [Escherichia coli coordinates] changed to gGA, AGc, guA, or gGc [lowercase letters are used to represent the base changes]), whereas the sixth (isolate Ind75) retained AGA(965-967); (ii) PCR products containing mutant 16S ribosomal DNA (rDNA) alleles transformed recipient strains to Tet(r) phenotypes, but transformants containing alleles with single substitutions (gGA and AGc) were less resistant than their Tet(r) parents; (iii) each of 10 Tet(r) mutants of reference strain 26695 (in which mutations were induced with metronidazole, a mutagenic anti-H. pylori agent) contained the normal AGA(965-967) sequence; and (iv) transformant derivatives of Ind75 and of one of the Tet(r) 26695 mutants that had acquired mutant rDNA alleles were resistant to tetracycline at levels higher than those to which either parent strain was resistant. Thus, tetracycline resistance in H. pylori results from an accumulation of changes that may affect tetracycline-ribosome affinity and/or other functions (perhaps porins or efflux pumps). We suggest that the rarity of tetracycline resistance among clinical isolates reflects this need for multiple mutations and perhaps also the deleterious effects of such mutations on fitness. Formally equivalent mutations with small but additive effects are postulated to contribute importantly to traits such as host specificity and virulence and to H. pylori's great genetic diversity.

Helicobacter pylori-Associated Diseases

Since the initial report 20 years ago by Marshall and Warren of an unidentified curved bacillus located on the gastric epithelium of patients with chronic active gastritis, the discovery of Helicobacter pylori and its association with a number of gastrointestinal diseases has revolutionized the field of gastroenterology. Although the association of H. pylori infection with peptic ulcer disease, chronic gastritis, mucosa-associated lymphoid tissue lymphoma, and gastric adenocarcinoma has been well documented over the past two decades, other areas remain less clear, including the role of H. pylori in gastropathy associated with nonsteroidal anti-inflammatory drugs, gastroesophageal reflux disease, and both uninvestigated and nonulcer dyspepsia. Although these areas still remain somewhat controversial, recent reports further clarify the role of H. pylori in these conditions. A review of the recent literature regarding H. pylori-associated diseases is presented along with recommendations for diagnosis and treatment of H. pylori infection.