The relationship between consumption of antimicrobial agents and the prevalence of primary Helicobacter pylori resistance

Recent trends in primary antimicrobial resistance of Helicobacter pylori in Finland

The antimicrobial susceptibility of Helicobacter pylori is an important predictor of the success of eradication therapy. To evaluate recent changes in primary antimicrobial resistance of H. pylori isolated from Finnish patients, the clinical records of H. pylori-positive patients referred for endoscopy to Herttoniemi Hospital (Helsinki, Finland) during 2000-2008 were investigated retrospectively. Stored H. pylori strains from 505 patients without previous eradication therapy were tested for clarithromycin, metronidazole, levofloxacin, tetracycline and amoxicillin susceptibility by Etest. Data on local consumption of antimicrobials were collected and correlations between consumption and resistance were calculated. During the 9-year study period, metronidazole resistance was high (range 29-59%, overall 41%). After an initial increase in clarithromycin resistance (0% in 2000 to 16% in 2003), resistance to clarithromycin decreased to 4% in 2008. No significant correlation was detected between consumption of macrolides and resistance of clarithromycin. Resistance to levofloxacin varied between 0% and 12%. Primary metronidazole resistance in H. pylori is at a high level, however levofloxacin and clarithromycin resistances are still at a reasonable level. Thus, primary clarithromycin resistance in H. pylori in Finland has not become such a problem as in many other countries. Primary resistance to the antimicrobials studied varied considerably from year to year.

Efficacy of standard triple therapy in the treatment of Helicobacter pylori infection: experience from Kuwait

INTRODUCTION

Recent studies suggest that the initial treatment success rates for H. pylori infection are falling below 80% in many parts of the world.

AIM

The aim of this study was to evaluate the efficacy of standard triple therapy in the treatment of H. pylori infection in Kuwait.

METHODS

Consecutive H. pylori positive patients were enrolled in the study to receive clarithromycin, amoxicillin and omeprazole for 10 days. H. pylori status was checked with 13C urea breath test 6 weeks after the end of therapy. Endoscopic findings was recorded in all patients.

RESULTS

One hundred forty-one patients (82 male and 59 females; mean age 41.8 years) were enrolled in the study. A total of seven patients were excluded from the per protocol analysis. The eradication rates in intention to treat (ITT) and per protocol (PP) were 72.3% (95% CI 64.2-79.5%) and 76.1% (95% CI 68-83%), respectively. The main endoscopic findings were normal in 47.5% and gastritis in 37.6%.

CONCLUSION

The efficacy of the current standard triple therapy for H. pylori eradication in our community is suboptimal. Confirmation for H. pylori eradication with noninvasive tests is recommended, especially in high-risk patients. New antimicrobial regimens for H. pylori eradication are considered necessary.

Helicobacter pylori resistance to metronidazole and clarithromycin in Ireland

INTRODUCTION

Helicobacter pylori eradication rates have fallen considerably in recent years. Antibiotic resistance is thought to be rising.

OBJECTIVES

To examine the levels of resistance to metronidazole (MTZ) and clarithromycin (CLA) in H. pylori, isolates were taken in a reference centre in Ireland from 2007 to 2008 and were compared to a similar cohort from a study in 1997.

METHOD

Antimicrobial susceptibilities were tested by E-test. Frequencies of spontaneous metronidazole and clarithromycin resistance were measured on an agar plate containing the antibiotics at concentrations of 2x and 4x minimum inhibition concentration values. Clinical data were obtained from charts, laboratory and endoscopy reports.

RESULTS

Two hundred and twenty-two patients were analyzed, 98 were females. Colonies amenable to culture were grown in 219 patients. Thirty-seven had prior attempts at eradication therapy (all with amoxicillin-CLA-proton pump inhibitor. A total of 31.5% of the patients had strains resistant to MTZ and 13.2% of the patients were noted to have strains resistant to CLA. About 8.6% of the patients had strains resistant to both the agents. CLA resistance was 9.3% in those who had no prior eradication therapy compared with 32.4% of those who had. CLA resistance increased from 3.9%, among treatment-naive patients in 1997, to 9.3% in our study. MTZ resistance was 29.1% in the treatment-naive population. In 1997, MTZ resistance in the treatment-naive cohort was 27.1%. MTZ resistance was more likely to occur in females (35.4 vs. 28.5%) than in males.

CONCLUSION

This study shows that resistance to CLA among Irish patients infected with H. pylori has increased since 1997. The future of treatment may well lie in the widespread use of sensitivity testing before the treatment. This would promote an accurate treatment.

High prevalence of clarithromycin-resistant Helicobacter pylori strains and risk factors associated with resistance in Madrid, Spain

Clarithromycin is one of the antibiotics used for the treatment of Helicobacter pylori infections, and clarithromycin resistance is the most important factor when it comes to predicting eradication failure. The present study analyzed H. pylori isolates for the presence of 23S rRNA gene mutations and determined the risk factors associated with resistance among H. pylori isolates collected in Madrid, Spain, in 2008. We studied 118 H. pylori strains isolated from the same number of patients. A total of 76.3% of the patients were born in Spain, 52.7% were children, 20.3% had previously been treated, and 66.1% were female. Clarithromycin resistance was determined by Etest. H. pylori strains were considered resistant if the MIC was ≥1 mg/liter. DNA extraction was carried out by use of the NucliSens easyMAG platform with NucliSens magnetic extraction reagents (bioMérieux). The DNA sequences of the 23S rRNA genes of clarithromycin-resistant and -sensitive strains were determined to identify specific point mutations. The vacA genotype and cagA status were determined by PCR. We found that 42 (35.6%) strains were resistant to clarithromycin by Etest. Etest results were confirmed by detection of the presence of point mutations in 34 (88.1%) of these strains. Eight H. pylori strains were resistant to clarithromycin by Etest but did not have a point mutation in the 23S rRNA gene. Mutation at A2143G was found in 85.3% of the strains, mutation at A2142G in 8.8%, and mutation at T2182C in 5.9%. Dual mutations were found in 8.8% of the strains. H. pylori clarithromycin-resistant strains were strongly associated with pediatric patients, with patients born in Spain, and with patients who had previously been treated (P ≤ 0.02). In addition, H. pylori strains resistant to clarithromycin more frequently presented the vacA s2/m2 genotype and were more likely to be cagA negative than susceptible strains (39.1% and 11.2%, respectively; P value < 0.001). We concluded that, in the present study, H. pylori clarithromycin-resistant strains are more frequently found in children, in patients mostly born in Spain, and in individuals who were previously treated for H. pylori infection and that these individuals are more likely colonized with a less virulent H. pylori strain.

In vitro activity of nemonoxacin, tigecycline, and other antimicrobial agents against Helicobacter pylori isolates in Taiwan, 1998-2007

The minimum inhibitory concentrations (MICs) of 330 nonduplicate Helicobacter pylori isolates to nemonoxacin, tigecycline, and eight other antimicrobial agents were determined by using the agar dilution method. Sequencing the quinolone resistance-determining regions (QRDRs) in the gyrA gene of these isolates was also performed. Resistance to clarithromycin showed an increasing trend during the ten-year study period and was highest (38%) in 2005. Tigecycline had potent in vitro activities against all isolates, with an MIC(90) of 0.06 μg/ml. Among the quinolones tested, nemonoxacin (MIC(50) of 0.12 μg/ml and MIC(90) of 0.25 μg/ml) and gemifloxacin had one to two-fold better in vitro activities than ciprofloxacin, levofloxacin, and moxifloxacin. Among the nine isolates (2.7%) with levofloxacin resistance, four (44.4%) were also resistant to metronidazole, three (33.3%) to clarithromycin, and two (22.2%) to amoxicillin. Isolates with levofloxacin resistance exhibited one or two of three amino acid alterations (Ser-70, Asn-87, and Asp-91) involved in QRDRs in the gyrA gene. A double mutation at Ser70Cys and Asn87Ile had a higher level of resistance. The results of this study suggest a potentially useful role of nemonoxacin and tigecycline in the treatment of infections caused by H. pylori. The gyrA mutation at Ser-70 is a novel finding and has an impact on levofloxacin resistance.

Sequential therapy for Helicobacter pylori eradication: a critical review

BACKGROUND

Alternative treatment regimens for standard triple therapy are urgently needed.

AIM

To critically review the evidence on the role of "sequential" regimen for the treatment of Helicobacter pylori infection.

METHODS

Bibliographical searches were performed in MEDLINE and international congresses.

RESULTS

Several pooled-data analyses and meta-analyses have demonstrated that sequential regimen is more effective than standard triple therapy. Sequential therapy is not affected by bacterial (CagA status, infection density) and host factors (underlying disease, smoking). Clarithromycin resistance seems to be the only factor reducing their efficacy. However, even in these patients, an acceptable >75% eradication rate can be achieved. Unfortunately, almost all the studies have been performed in Italy. Whether it is necessary to provide the drugs sequentially or if the 4 components of sequential therapy can be given concurrently is unclear. Nonbismuth quadruple therapy seems to be an effective and safe alternative to triple therapy and is less complex than sequential therapy.

CONCLUSIONS

Sequential therapy is a novel promising treatment approach that deserves consideration as a treatment strategy for H. pylori infection. However, further robust assessment across a much broader range of patients is required before sequential therapy could supplant existing treatment regimens and be generally recommended in clinical practice.

Clinical trial: irsogladine maleate, a mucosal protective drug, accelerates gastric ulcer healing after treatment for eradication of Helicobacter pylori infection--the results of a multicentre, double-blind, randomized clinical trial (IMPACT study)

BACKGROUND

Helicobacter pylori eradication therapy alone is not sufficient to heal all gastric ulcers.

AIM

To verify the efficacy of treatment with irsogladine maleate between the termination and assessment of treatment for eradicating H. pylori in a double-blind study.

METHODS

Three hundred and twenty-two patients with a single H. pylori-positive gastric ulcer were given eradication treatment, then assigned randomly to a treatment group [given 4 mg/day irsogladine maleate (n = 150)] or a control group [given a placebo (n = 161)]. The gastric ulcer healing rates were compared after 7 weeks of treatment.

RESULTS

The healing rate was significantly higher in the irsogladine maleate group (83.0%) than in the placebo group (72.2%; chi2 test, P = 0.0276). In the subgroup analysis of cases of eradication failure, the gastric ulcer healing rate was significantly higher in the irsogladine maleate group (57.9%) than in the placebo group (26.1%; chi2 test, P = 0.0366).

CONCLUSIONS

Irsogladine maleate was effective for treating gastric ulcer after H. pylori eradication. The high healing rates observed in patients with or without successful eradication demonstrate the usefulness of irsogladine maleate treatment regardless of the outcome of eradication.

Annual change of primary resistance to clarithromycin among Helicobacter pylori isolates from 1996 through 2008 in Japan

BACKGROUND

Recent studies have shown that the combination of proton pump inhibitor, amoxicillin and clarithromycin is one of the best choices for Helicobacter pylori eradication therapy. However, increasing number of cases of H. pylori infection showing resistance to clarithromycin therapy has been reported and this is currently the main cause of eradication failure. We investigated the annual changes of the antimicrobial susceptibility to clarithromycin, amoxicillin and minocycline during a period of 12 years in Japan.

METHODS

This study comprised 3521 patients (mean age (SD), 55.4 (13.7) years-old, 2467 males and 1054 females) positive for H. pylori as assessed by microaerobic bacterial culture from 1996 through 2008. All patients were previously untreated for H. pylori and were enrolled in the study to assess primary resistance to the three antibiotics.

RESULTS

The overall primary resistance to clarithromycin, amoxicillin and minocycline were 16.4%, (577/3521), 0.03% (1/3521) and 0.06% (2/3521), respectively. From 1996 through 2004, the resistance rate to clarithromycin increased gradually to approximately 30% and then it remained without marked fluctuation since 2004. Analysis by gender showed a significant increase (p < .0001) in resistance rate to clarithromycin among females (217/1057, 20.6%) compared to males (360/2467, 14.6%). Analysis by age, disclosed significantly (p < .0001) higher resistance rate to clarithromycin in patients of more than 65-years-old compared to the younger population.

CONCLUSIONS

The resistance rate of H. pylori infection to clarithromycin in Japan has increased gradually to approximately 30% from 1996 through 2004, and remained unchanged since 2004. Elderly and females were at high risk of having resistance to clarithromycin. Our results suggested that the level of clarithromycin resistance in Japan has now risen to the point where it should no longer be used as empiric therapy.

Prevalence of antimicrobial resistance in Helicobacter pylori isolates in Taiwan in relation to consumption of antimicrobial agents

During 1998-2004, a total of 218 Helicobacter pylori isolates were obtained from patients who were randomised to receive one of the following regimens in a medical centre in Taiwan: lansoprazole, amoxicillin and clarithromycin (LAC) therapy; or lansoprazole, metronidazole and clarithromycin (LMC) therapy. In the LMC group, resistance rates for metronidazole and clarithromycin reduced from 48.6% (1998-2000) to 20.4% (2001-2004) (P<0.05) and from 13.5% to 6.3% (P<0.05), respectively. Analysis of annual antimicrobial consumption found that metronidazole use was slowly decreased both in the total population and in gastrointestinal disease patients. The per-protocol analysis revealed a higher eradication rate for patients using LMC therapy in 2001-2004 (82.6% vs. 75.0%), whilst there was similar efficacy for LAC therapy (84.8% vs. 84.2%). This observation suggests an effective programme to control H. pylori antibiotic resistance and hence elevate its cure rate.

Eradication of helicobacter pylori to prevent gastroduodenal diseases: hitting more than one bird with the same stone

Helicobacter pylori (H. pylori) are gram-negative bacteria that selectively colonizes the gastric mucosa. The prevalence of H. pylori infection varies from 20 to 50% in industrialized countries to over 80% in developing countries. The infection may persist lifelong without specific treatment. Prolonged infection and inflammation due to bacterial virulence and host genetic factors will lead to chronic gastritis. A certain portion of infected patients then develop more severe pathologies such as peptic ulcer (10-15%), gastric cancer (1%), and mucosa-associated lymphoid tissue lymphoma (50.01%). Although the majority of infected patients remain asymptomatic, much of the evidence has shown that eradication of H. pylori infection can reduce the recurrence of peptic ulcer and benefit a substantial portion of patients with nonulcer dyspepsia. Though controversial in population-based clinical trials, several cost-effectiveness analyses also reveal that H. pylori eradication is cost effective in the primary prevention of gastric cancer. Therefore, the discovery of H. pylori offers the chance to prevent several gastroduodenal diseases by means of their eradication. In other words, gastroenterologists could hit more than one bird with one stone. However, there are concerns regarding application of a 'test and treat' strategy in the general population. In this review, we will focus on current evidence of H. pylori eradication in the primary and secondary prophylaxis of gastric cancer and peptic ulcer disease.

Antibiotic resistance of Helicobacter pylori

Helicobacter pylori are spiral-shaped, Gram-negative bacteria that colonize the stomachs of more than half the world's population. H. pylori colonization is the most common cause of chronic active gastritis and peptic ulcer disease, which directly related to gastric carcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. However, the efficacies of eradication therapies are not satisfying mainly because of bacterial resistance to antibiotics. This article makes a brief summary on the recent research related to the antibiotic resistance of H. pylori.

Gastric Cancer Consensus conference recommends Helicobacter pylori screening and treatment in asymptomatic persons from high-risk populations to prevent gastric cancer

Gastric adenocarcinoma remains a common cause of death worldwide, and there is convincing evidence that this cancer is causally linked to Helicobacter pylori. The first Asian-Pacific Gastric Cancer Consensus brought together leading authorities in the field including the authors, and systematically reviewed all of the available evidence for the role of H. pylori, diet and other risk factors in this malignancy. The consensus conference boldly recommended population-based screening and treatment for H. pylori in particularly high-risk population settings. The evidence for these recommendations is summarized in this report, and the global and U.S. implications are considered.

Asia-Pacific consensus guidelines on gastric cancer prevention

BACKGROUND AND AIM

Gastric cancer is a major health burden in the Asia-Pacific region but consensus on prevention strategies has been lacking. We aimed to critically evaluate strategies for preventing gastric cancer.

METHODS

A multidisciplinary group developed consensus statements using a Delphi approach. Relevant data were presented, and the quality of evidence, strength of recommendation, and level of consensus were graded.

RESULTS

Helicobacter pylori infection is a necessary but not sufficient causal factor for non-cardia gastric adenocarcinoma. A high intake of salt is strongly associated with gastric cancer. Fresh fruits and vegetables are protective but the use of vitamins and other dietary supplements does not prevent gastric cancer. Host-bacterial interaction in H. pylori infection results in different patterns of gastritis and differences in gastric acid secretion which determine disease outcome. A positive family history of gastric cancer is an important risk factor. Low serum pepsinogens reflect gastric atrophy and may be useful as a marker to identify populations at high risk for gastric cancer. H. pylori screening and treatment is a recommended gastric cancer risk reduction strategy in high-risk populations. H. pylori screening and treatment is most effective before atrophic gastritis has developed. It does not exclude the existing practice of gastric cancer surveillance in high-risk populations. In populations at low risk for gastric cancer, H. pylori screening is not recommended. First-line treatment of H. pylori infection should be in accordance with national treatment guidelines.

CONCLUSION

A strategy of H. pylori screening and eradication in high-risk populations will probably reduce gastric cancer incidence, and based on current evidence is recommended by consensus.

Changing antimicrobial susceptibility epidemiology of Helicobacter pylori strains in Japan between 2002 and 2005

Surveillance of Helicobacter pylori antimicrobial susceptibility reflecting the general population in Japan is limited. The antimicrobial susceptibilities of 3,707 H. pylori strains isolated from gastric mucosa samples of previously untreated patients diagnosed with gastroduodenal diseases at 36 medical facilities located throughout Japan between October 2002 and September 2005 were evaluated. Using an agar dilution method for antimicrobial susceptibility testing of H. pylori, the MIC distributions and trends during the study period for clarithromycin, amoxicillin, and metronidazole were studied. While the MIC(50) and MIC(90) for clarithromycin did not change during the 3-year period, the MIC(80) showed a 128-fold increase. Furthermore, the rate of resistance increased yearly from 18.9% (2002 to 2003) to 21.1% (2003 to 2004) and 27.7% (2004 to 2005). With a resistance rate of 19.2% among males compared to 27.0% among females, a significant gender difference was observed (P < 0.0001). Our study shows that in Japan, there is an evolving trend towards increased resistance to clarithromycin with geographical and gender differences as well as between clinical disease conditions. No significant changes in resistance were observed for amoxicillin and metronidazole during the period. While the benefit of H. pylori antimicrobial susceptibility testing has been debated in Japan, current empirical regimens are not based on susceptibility data representative of the general population. The development of an effective H. pylori eradication regimen in Japan will require continued resistance surveillance as well as a better understanding of the epidemiology of resistance.

Review article: Helicobacter pylori eradication for the prevention of gastric cancer

BACKGROUND

Gastric cancer is the fourth most common cancer and second leading cause of cancer-related death worldwide. A clear association between Helicobacter pylori infection and gastric cancer was established years ago. H. pylori eradication may be an effective approach to decrease morbidity and mortality of gastric cancer.

AIM

To discuss current evidence of H. pylori eradication for prevention of gastric cancer.

RESULTS

Recent studies have shown that the association between H. pylori and gastric cancer has probably been underestimated. This may have resulted from negative H. pylori status in subjects after loss of colonisation in the presence of atrophic gastritis and intestinal metaplasia, prior to development of gastric cancer. The recognition of the central role of H. pylori in carcinogenesis has increased expectations of gastric cancer prevention by H. pylori eradication. A primary preventive effect of eradication in subjects with H. pylori-induced gastritis has been demonstrated. However, a secondary preventive effect in patients with pre-malignant gastric lesions is still controversial, especially in patients with intestinal metaplasia and dysplasia.

CONCLUSIONS

At this moment, H. pylori eradication seems indicated at the earliest stage of gastric carcinogenesis. This treatment policy requires confirmation; results of ongoing randomised controlled trials are therefore eagerly awaited.

The efficacy of bismuth containing quadruple therapy as a first-line treatment option for Helicobacter pylori

BACKGROUND

Helicobacter pylori eradication rates have tended to decrease recently, mostly due to increasing antibiotic-resistance. The present study aimed to compare the efficacy of bismuth-based quadruple regimen with proton pump inhibitor-based triple regimen for eradication of H. pylori.

METHODS

Consecutive H. pylori-positive patients with non-ulcer dyspepsia were randomized into one of two regimens: (i) bismuth subsalicylate 300 mg q.i.d., lansoprazole 30 mg b.i.d., tetracycline 500 mg q.i.d. and metronidazole 500 mg t.i.d. (BLTM group) for 14 days; (ii) lansoprazole 30 mg b.i.d., amoxicillin 1 g b.i.d and clarithromycin 500 mg b.i.d. (LAC) for 14 days. Gastroscopy and (14)C-Urea breath test (UBT) were performed before enrollment, and UBT only was repeated for 6 weeks after treatment.

RESULTS

A total of 240 patients were randomized into groups and 212 of them completed the protocols. The 'intention-to-treat' (ITT) and 'per protocol' (PP) H. pylori eradication rates were 70% (95%CI 61-78) and 82.3% (95%CI 74-89) in the BLTM group, and 57.5% (95%CI 48-66) and 62.7% (95%CI 53-71) in the LAC group. The BLTM treatment achieved a significantly better eradication rate compared with LAC treatment in PP analysis (82.3% vs. 62.7%, P = 0.002). Mild to severe side-effects, which were more frequent in the BLTM group, were reported in 18.2% of the patients.

CONCLUSION

The bismuth-based quadruple regimen achieved a better eradication rate compared with proton pump inhibitor-based triple regimens as a first-line eradication option for H. pylori in our population.

High Helicobacter pylori resistance rate to clarithromycin in Turkey

GOALS

To assess the resistance of Helicobacter pylori to clarithromycin in Turkey.

BACKGROUND

Recent studies have emphasized the remarkable reduction in H. pylori eradication rates. Resistance to clarithromycin is the most important factor affecting the success of H. pylori eradication therapies.

STUDY

The study involved 110 consecutive adult dyspeptic patients infected with H. pylori. Resistance to clarithromycin was studied by real-time polymerase chain reaction method on gastric biopsy specimens.

RESULTS

Of the 110 patients, 56 (50.9%) were male and mean age (+/-SD) was 45.1+/-13.1 years. Overall, 53 (48.2%) patients were found to be resistant to clarithromycin. Resistance to clarithromycin was not statistically associated with age, sex, previous macrolide use, residence (urban/rural), education status, and presence of peptic ulcer.

CONCLUSIONS

The rate of resistance to clarithromycin was found to be markedly high. This result may explain the recently reported low success rates of H. pylori eradication therapies with clarithromycin.

Helicobacter pylori detection and antimicrobial susceptibility testing

The discovery of Helicobacter pylori in 1982 was the starting point of a revolution concerning the concepts and management of gastroduodenal diseases. It is now well accepted that the most common stomach disease, peptic ulcer disease, is an infectious disease, and all consensus conferences agree that the causative agent, H. pylori, must be treated with antibiotics. Furthermore, the concept emerged that this bacterium could be the trigger of various malignant diseases of the stomach, and it is now a model for chronic bacterial infections causing cancer. Most of the many different techniques involved in diagnosis of H. pylori infection are performed in clinical microbiology laboratories. The aim of this article is to review the current status of these methods and their application, highlighting the important progress which has been made in the past decade. Both invasive and noninvasive techniques will be reviewed.

Characteristics of antibiotic resistance of Helicobacter pylori strain isolated from patients

AIM: To analyze the resistance of clinical isolated H. pylori strain to common antibiotics.

METHODS: H. pylori strains were obtained by inoculating the specimens of 61 patients in the selective media for 96 h at 37°C under microaerophilic conditions. Kirby-Bauer test was performed to detect the drug sensitivity of the 61 isolated H. pylori strains to metronidazole, clarithromycin, amoxicillin and furazolidone.

RESULTS: The antibiotic resistant rates of H. pylori strains to metronidazole, clarithromycin, amoxicillin and furazolidone were 54.1%, 37.7%, 41.0% and 45.9%, respectively, and there were no significant difference among them (P > 0.05). The resistance H. pylori strains to metronidazole was related to the sex of patients (P = 0.037), and the resistance of H. pylori strains to metronidazole, clarithromycin and amoxicillin was closely related to the history of antibiotic usage (P = 0.028; P = 0.034; P = 0.005). No significant relationship existed between the antibiotic resistance of H. pylori in the type of disease and the age of patients (P > 0.05).

CONCLUSION: H. pylori has high resistance to metronidazole, clarithromycin, amoxicillin, and furazolidone, which is associated with the history of antibiotic application, but not with the disease category and age of patients.

Eradication of Helicobacter pylori with triple therapy: an epidemiologic analysis of trends in Turkey over 10 years

BACKGROUND

There is increasing concern about the efficacy of current regimens for the eradication of Helicobacter pylori.

OBJECTIVES

This study examined rates of H. pylori eradication with a commonly used triple-therapy regimen consisting of a proton pump inhibitor (PPI), clarithromycin, and amoxicillin in trials performed in Turkey from 1996 to 2005. It also investigated the relationship between eradication rates and the duration of treatment (7, 10, or 14 days), choice of PPI, and indication for treatment (dyspepsia or peptic ulcer).

METHODS

This was a retrospective epidemiologic analysis. Articles concerning H. pylori eradication in Turkey that were published in peer-reviewed national and international journals were identified through searches of MEDLINE using the terms Helicobacter, eradication, and Turkey, and of the Turkish Medical Index using the terms Helicobacter and eradication. Abstracts from the Turkish Gastroenterology Congress from 1996 through 2005 were searched manually. Open-label trials, controlled trials, treatment arms, and case series that included a triple-therapy regimen consisting of standard doses of any PPI (omeprazole 20 mg BID, lansoprazole 30 mg BID, pantoprazole 40 mg BID, or esomeprazole 40 mg BID) with clarithromycin 500 mg BID and amoxicillin 1 g BID for 7 to 14 days were selected for analysis. Trials including patients who had undergone a previous attempt at eradication of H. pylori were excluded.

RESULTS

Of 138 trials or treatment arms identified, 94 met the criteria for inclusion (3637 subjects). The pooled eradication rate was 68.8% (95% CI, 67.3-70.3). A marked decrease in eradication was noted after 2000. Pooled eradication rates each year from 1996 through 2005 were 79.4%, 83.7%, 81.8%, 81.8%, 75.1%, 61.3%, 65.6%, 65.1%, 55.3%, and 61.1%, respectively. Eradication rates were not affected by the duration of treatment, choice of PPI, or indication for treatment.

CONCLUSIONS

Rates of H. pylori eradication with the triple-therapy regimen decreased in Turkey over the 10-year period studied. In an era of increasing clarithromycin use, the effectiveness of this regimen for H. pylori eradication appears to require reassessment.

Effective regimens for the treatment of Helicobacter pylori infection

Successful Helicobacter pylori eradication therapy remains a challenge in medical practice. Currently, a proton pump inhibitor-based triple therapy containing clarithromycin, amoxicillin or nitroimidazole for 7 days is the recommended first-line treatment approach with an expected eradication success rate of approximately 80%. As a second-line treatment option in the case of failure, a ranitidine bismuth citrate-based quadruple therapy is currently recommended curing another 80% of patients, leaving a subset of patients with persistent H. pylori infection. For these patients, promising rescue options have been evaluated including regimens that contain rifabutin, quinolones, furazolidone or high-dose amoxicillin. The role of susceptibility testing is still under discussion. It is not generally recommended prior to first-line treatment but guidelines propose a role for culture and antibiotic sensitivity testing after failure of the second attempt. Meanwhile, data on the geographic distribution of resistance pattern are available and may guide therapeutic decisions with regard to the combination of antibiotics chosen for the individual patients aiming at 100% cure rate in each individual patient.

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.

Furazolidone-based triple therapy for H pylori gastritis in children

AIM: To evaluate the furazolidone-based triple therapy in children with symptomatic H pylori gastritis.

METHODS: A prospective and consecutive open trial was carried out. The study included 38 patients with upper digestive symptoms sufficiently severe to warrant endoscopic investigation. H pylori status was defined based both on histology and on positive ¹³C-urea breath test. Drug regimen was a seven-day course of omeprazole, clarithromycin and furazolidone (100 mg, 200 mg if over 30 kg) twice daily. Eradication of H pylori was assessed two months after treatment by histology and ¹³C-urea breath test. Further clinical evaluation was performed 7 d, 2 and 6 mo after the treatment.

RESULTS: Thirty-eight patients (24 females, 14 males) were included. Their age ranged from 4 to 17.8 (mean 10.9 ± 3.7) years. On intent-to-treat analysis (n = 38), the eradication rate of H pylori was 73.7% (95% CI, 65.2%-82%) whereas in per-protocol analysis (n = 33) it was 84.8% (95% CI, 78.5%-91%). All the patients with duodenal ulcer (n = 7) were successfully treated (100% vs 56.2% with antral nodularity). Side effects were reported in 26 patients (68.4%), mainly vomiting (14/26) and abdominal pain (n = 13). Successfully treated dyspeptic patients showed improvement in 78.9% of H pylori-negative patients after six months and in 50% of H pylori-positive patients after six months of treatment.

CONCLUSION: Triple therapy with furazolidone achieves moderate efficacy in H pylori treatment. The eradication rate seems to be higher in patients with duodenal ulcer.

Helicobacter pylori treatment: a practical approach

The treatment of Helicobacter pylori infection has become complicated by the lack of new treatment regimens and the emergence of drug resistant strains of H. pylori. Metronidazole and clarithromycin resistance are common in developed countries. Eradication rates have been falling in trials and in clinical practice around the world. A practical approach to the treatment of patients with H. pylori infection and those who fail initial eradication therapy is discussed.

Efficacy and safety of rifabutin-containing 'rescue therapy' for resistant Helicobacter pylori infection

BACKGROUND

Current 'rescue' therapies provide inadequate Helicobacter pylori eradication rates because of antibiotic resistance.

AIM

To test the efficacy of a modified triple regimen combining rifabutin, pantoprazole and amoxicillin as rescue therapy for patients in whom eradication of H. pylori had failed standard clarithromycin-based triple therapy.

METHODS

One hundred and thirty patients (mean age 51.7 +/- 14.8 years) who had failed one or more eradication attempts with omeprazole, clarithromycin and amoxicillin were treated for 12 days with rifabutin 150 mg daily, amoxicillin 1 g or 1.5 g t.d.s, and pantoprazole 80 mg t.d.s.

RESULTS

The intention-to-treat and per-protocol eradication rates were 90.8/90.8%. Metronidazole or/and clarithromycin resistance had no significant impact on H. pylori eradication rates. A higher overall eradication rate of 96.6% (95% CI: 92.1-101%) was obtained in patients treated with a regimen containing 1.5 g amoxicillin t.d.s compared with 90.7% (95% CI: 82-98.6%) using a regimen with 1 g amoxicillin t.d.s but the difference was not significant. Side-effects reported in 40% of patients were mild.

CONCLUSION

A 12-day course of low dose of rifabutin with an increased dose of amoxicillin and pantoprazole is well-tolerated and highly effective against dual-resistant H. pylori infection after failure of triple therapy.

Helicobacter pylori eradication has the potential to prevent gastric cancer: a state-of-the-art critique

Helicobacter pylori infection continues to play a key role in gastric diseases. Colonization of the gastric mucosa with the bacterium invariably results in the development of chronic gastritis and subsets of patients have a progression of the chronic gastritis to either ulcer or cancer. Epidemiological evidence indicates that the proportion of all gastric cancers attributable to H. pylori infection, and hence potentially preventable upon elimination of this risk factor, is somewhere in the range of 60% to 90%. This portends significant benefit in terms of morbidity and mortality, not least in populations with high prevalence of H. pylori infection coupled with high incidence of gastric cancer. The effect of prophylactic H. pylori eradication on gastric cancer incidence in humans remains unknown, however. Results from randomized trials are eagerly awaited, but availability of strong conclusive results may take many years. A growing number of studies show considerable variation in risk for gastric cancer development, depending on H. pylori strain type and the genetic predisposition of the host. There is also a remote possibility that elimination of the infection may have adverse health implications (e.g., antibiotic resistance), and therefore "simple" risk stratification and targeted chemoprevention is required. Based on "in depth" evidence presented at this workshop, the majority of the scientific task force favored a search-and-treat strategy in first-degree relatives of gastric cancer patients and an overwhelming majority felt that a more general screen-and-treat strategy should be focused in the first instance on a population with a high incidence of H. pylori-associated diseases.

Susceptibilities to clarithromycin, amoxycillin and metronidazole of Helicobacter pylori isolates from the antrum and corpus in Tokyo, Japan, 1995-2001

The aim of this study was to determine the susceptibilities to clarithromycin, amoxycillin and metronidazole of Helicobacter pylori isolates from the antrum and corpus of Japanese patients examined during the period 1995-2001. There was an increase, from 6.2% in 1995 to 22.1% in 2000-2001, in the proportion of patients infected with clarithromycin-resistant H. pylori. Of patients infected with clarithromycin-resistant H. pylori, 39.1% were infected with both clarithromycin-susceptible and -resistant H. pylori. Furthermore, the MIC90 of clarithromycin for H. pylori rose from < 1 mg/L in 1995-1998 to 8 mg/L in 1999. In contrast, the MIC90s of amoxycillin and metronidazole were < or = 0.125 and 4 mg/L, respectively, throughout the study period. The results showed that, while most H. pylori isolates were susceptible to amoxycillin and metronidazole, resistance to clarithromycin among H. pylori isolates increased markedly in Japan during 1995-2001. The results also indicated a need to test the susceptibility of H. pylori isolates from more than two samples obtained from two different sites in the stomach of a single patient in order to diagnose the presence of clarithromycin-resistant H. pylori correctly.

Polymerase chain reaction--restriction fragment length polymorphism analysis of clarithromycin-resistant Helicobacter pylori infection in children using stool sample

BACKGROUND

To analyze clarithromycin-resistant Helicobacter pylori infection in children, we developed a method of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis using stool samples.

MATERIALS AND METHODS

Twenty-three children without significant upper abdominal symptoms were included (mean age 7.0 years). Of these, 18 and five were diagnosed as H. pylori-positive and -negative, respectively, by the H. pylori stool antigen test (HpSA). The DNA from the stool samples was purified using the QIAamp DNA Stool Minikit (QIAGEN). The PCR was performed on the purified DNA using oligonucleotide primers designed to amplify the 23S rRNA gene of H. pylori. The PCR products were reacted with restriction enzymes MboII, BceAI, and BsaI to detect mutations A2142G, A2142C, and A2143G, respectively.

RESULTS

Sixteen of the 18 HpSA-positive samples were PCR-positive, and all five HpSA-negative samples were PCR-negative. Thus, the PCR had 89% sensitivity and 100% specificity, with 91% accuracy in reference to HpSA. Of the 16 PCR-positive samples, one and four were digested with MboII and BsaI, respectively, indicating 31% prevalence of CAM-resistance.

CONCLUSIONS

We conclude that the PCR-RFLP using stool samples is a rapid and reliable method to noninvasively detect clarithromycin-resistant H. pylori infection in children. It may be useful before choosing regimens of H. pylori eradication.

Changing trends in peptic ulcer prevalence in a tertiary care setting in the Philippines: a seven-year study

BACKGROUND AND AIMS

The declining global prevalence of peptic ulcer disease (PUD) might be because of the decreasing prevalence of Helicobacter pylori (Hp) infection. The aims of the present study were to determine the prevalence of PUD during a 7-year period and to investigate its relationship with the prevalence of Hp infection during the same period.

METHODS

All upper gastrointestinal endoscopies carried out at Santo Tomas Hospital in Manila from January 1996 to December 2002 were evaluated. Endoscopies reporting gastric ulcers (GU) and duodenal ulcers (DU) with Hp status were analyzed.

RESULTS

A total of 15 341 endoscopies were evaluated. Overall, 2600 (16.95%) GU and 1575 (10.27%) DU were identified. There was a decreasing trend in the prevalence of GU (P < 0.0001) and DU (P < 0.0001) during the study period. Overall PUD prevalence declined from 35.87% in 1996 to 18.80% in 2002. This decline was seen for both GU and DU (20.05 vs 14.34%, and 15.83 vs 7.02%, respectively). The prevalence of Hp infection decreased significantly from 1996 to 2002 for both GU and DU (68.13 vs 33.48%, P < 0.0001; and 76.67 vs 36.50%, P < 0.0001, respectively). The decrease in Hp prevalence was significantly related to the decrease in ulcer prevalence (r = 0.97, P = 0.0004 for GU; r = 0.89, P = 0.0079 for DU; and r = 0.92, P = 0.0035 for all PUD). The prevalence of bleeding secondary to PUD remained stable during the 7-year period (P = 0.87).

CONCLUSIONS

During the 7-year period, there was a significant decline in the prevalence of PUD. This decline in PUD prevalence was associated with a corresponding decrease in Hp prevalence.

Growth competition of macrolide-resistant and -susceptible Helicobacter pylori strains

We examined population dynamics in a mixed culture of clonally related macrolide-resistant and -susceptible Helicobacter pylori strains isolated from a single patient. The resistant strain had a macrolide resistance-conferring A2143G mutation in the 23S rRNA gene. The growth rate of these two strains did not apparently differ when cultured separately. On the other hand, by conducting sequential passage of a mixed culture of the resistant and the susceptible strains, the ratio of the resistant strain to the susceptible strain in the culture typically decreased per passage, indicating that the resistance imposed a significant disadvantage on bacterial fitness in the population.

In vitro induction of resistance to metronidazole, and analysis of mutations in rdxA and frxA genes from Helicobacter pylori isolates

In clinical Helicobacter pylori isolates, metronidazole resistance has been associated with mutations in the rdxA and frxA genes. The aim of this study was to examine the role of the rdxA and frxA genes after the in vitro induction of metronidazole resistance. A total of five suscep-tible H. pylori isolates were initially exposed to different subinhibitory metronidazole concentrations to induce in vitro resistance to metronidazole. Susceptible and resistant strains after the in vitro induction of resistance were examined to evaluate mutations of the rdxA and frxA genes by sequence analysis. After the in vitro induction of resistance, analysis revealed that two and four susceptible strains developed resistance when cultured with 0.3 microg/ml and 0.6 microg/ml of metronidazole, respectively. Before and after the induction of resistance, none of the susceptible strains that developed low and moderate levels of resistance presented any mutation in either of the evaluated genes, whereas strains with high-level metronidazole resistance contained a simple mutation of the frxA gene, but no specific changes in the rdxA gene. Strains with moderate-level resistance contained both single and multiple mutations of rdxA and frxA, respectively, and the low-level-metronidazole-resistant strain contained a single mutation in the frxA gene, without any significant change in the rdxA gene. In this study, the strains that developed resistance were mainly associated with mutations of the frxA gene, suggesting the possibility that inactivation of this gene could originate metronidazole resistance. The results after the in vitro induction of resistance to metronidazole suggested the presence of additional metronidazole resistance mechanisms, other than mutations of the rdxA and/or frxA genes.

[Helicobacter pylori resistance to metronidazole and clarythromicin: descriptive analysis 1997-2000]

BACKGROUND AND OBJECTIVE

We aimed to assess the resistance of H. pylori to clarithromycin and metronidazole, in patients with and without previous eradication treatment, in a geographic area from the north of Spain. We also analyzed the evolution of resistance rates and its relationships with annual antibiotic consumption.

PATIENTS AND METHOD

Retrospective study including all patients with H. pylori infection and positive culture from January 1997 to December 2000. Minimal inhibitory concentrations (MIC) determined by the E test were used to report the clarithromycin (MIC > 2 mg/l) and metronidazole (MIC > 32 mg/l) resistance.

RESULTS

A total of 537 clinical H. pylori isolates from patients without (n = 389) and with previous eradication treatment (n = 148) were studied. H. pylori resistance to clarithromycin and metronidazole was found in 8.7% (95% CI, 6.1-12) and 13.8% (95% CI, 10.4-17.3) patients without previous eradication treatment and in 39.2% (95% CI, 31.3-47.1) and 37.8% (95% CI, 30-45.7) patients with previous eradication treatment (p < 0.001), respectively. Clarithromycin resistance remained stable (1997: 9.7%; 1998: 5.7%; 1999: 11.8%; 2000: 6.2%) whereas metronidazole resistance decreased over the 4 years study period (1997: 38.7%; 1998: 15.1%; 1999: 9%; 2000: 6.9%). We did not observe any clear relationship between resistance's evolution and antibiotic annual consumption.

CONCLUSIONS

In our geographic area, primary resistance rates for clarithromycin remained stable whereas resistance for metronidazole decreased over the 4 years period.

New tumor necrosis factor-alpha-inducing protein released from Helicobacter pylori for gastric cancer progression

PURPOSE

To investigate the association between Helicobacter pylori infection and its inflammatory reaction in gastritis, gastric ulcer, and gastric cancer, a new tumor necrosis factor-alpha (TNF-alpha)-inducing protein of H. pylori was studied.

METHODS

The HP0596 gene of H. pylori was identified as the TNF-alpha-inducing protein (Tipalpha) gene from genome sequence of H. pylori strain 26695. Using recombinant Tipalpha (rTipalpha) and deleted Tipalpha (rdel-Tipalpha) proteins, the latter of which lacks six amino acids containing two cysteines in the N-terminal domain, we examined their activities in TNF-alpha gene expression and NF-kappaB activation in both Bhas 42 (v-H-ras transfected BALB/3T3) cells and mouse gastric epithelial cell line MGT-40, and in vitro transformation of Bhas 42 cells.

RESULTS

Tipalpha protein as a homodimer form (38 kDa) was found in both extracts and culture medium of various H. pylori strains. rTipalpha significantly induced TNF-alpha gene expression and NF-kappaB activation in both Bhas 42 cells and MGT-40, and induced in vitro transformation of Bhas 42 cells. However, rdel-Tipalpha did not. Treatment with MG-132, a proteasome inhibitor, inhibited translocation of NF-kappaB p65, and abrogated TNF-alpha induction induced by Tipalpha protein.

CONCLUSION

Tipalpha is a new carcinogenic factor released from H. pylori mediated through NF-kappaB activation.

New tumor necrosis factor-alpha-inducing protein released from Helicobacter pylori for gastric cancer progression

PURPOSE

To investigate the association between Helicobacter pylori infection and its inflammatory reaction in gastritis, gastric ulcer, and gastric cancer, a new tumor necrosis factor-alpha (TNF-alpha)-inducing protein of H. pylori was studied.

METHODS

The HP0596 gene of H. pylori was identified as the TNF-alpha-inducing protein (Tipalpha) gene from genome sequence of H. pylori strain 26695. Using recombinant Tipalpha (rTipalpha) and deleted Tipalpha (rdel-Tipalpha) proteins, the latter of which lacks six amino acids containing two cysteines in the N-terminal domain, we examined their activities in TNF-alpha gene expression and NF-kappaB activation in both Bhas 42 (v-H-ras transfected BALB/3T3) cells and mouse gastric epithelial cell line MGT-40, and in vitro transformation of Bhas 42 cells.

RESULTS

Tipalpha protein as a homodimer form (38 kDa) was found in both extracts and culture medium of various H. pylori strains. rTipalpha significantly induced TNF-alpha gene expression and NF-kappaB activation in both Bhas 42 cells and MGT-40, and induced in vitro transformation of Bhas 42 cells. However, rdel-Tipalpha did not. Treatment with MG-132, a proteasome inhibitor, inhibited translocation of NF-kappaB p65, and abrogated TNF-alpha induction induced by Tipalpha protein.

CONCLUSION

Tipalpha is a new carcinogenic factor released from H. pylori mediated through NF-kappaB activation.

Antibacterial activity of hydrolyzable tannins derived from medicinal plants against Helicobacter pylori

Helicobacter pylori is a major etiological agent in gastroduodenal disorders. In this study, we isolated 36 polyphenols and 4 terpenoids from medicinal plants, and investigated their antibacterial activity against H. pylori in vitro. All hydrolyzable tannins tested demonstrated promising antibacterial activity against H. pylori. Monomeric hydrolyzable tannins revealed especially strong activity. Other compounds demonstrated minimal antibacterial activity with a few exceptions. A monomeric hydrolyzable tannin, Tellimagrandin I demonstrated time- and dose-dependent bactericidal activity against H. pylori in vitro. On the other hand, hydrolyzable tannins did not affect the viability of MKN-28 cells derived from human gastric epithelium. Hydrolyzable tannins, therefore, have potential as new and safe therapeutic regimens against H. pylori infection. Furthermore, we investigated effects of hydrolyzable tannins on lipid bilayer membranes. All the hydrolyzable tannins tested demonstrated dose-dependent membrane-damaging activity. However, it remains to be elucidated whether their membrane-damaging activity directly contributes to their antibacterial action.

Review article: impact of Helicobacter pylori on society-role for a strategy of 'search and eradicate'

Helicobacter pylori infection is causally related to gastric cancer, a malignancy associated with high morbidity and poor prognosis, and to peptic ulcer disease, a disease with high morbidity and modest mortality. Theoretically, H. pylori eradication is the most practical means of preventing gastric cancer and peptic ulcer disease. From a public policy perspective, the current evidence is insufficient to assess accurately the magnitude of the benefits of a universal 'search and treat' approach. Nonetheless, it is possible to identify high-risk patients for whom testing for the presence of H. pylori infection, with the intention-to-treat infected individuals is currently indicated. This list includes patients with ulcers or dyspepsia, first-degree relatives of patients with peptic ulcer or gastric cancer, gastric cancer patients after potentially curative resection of their gastric cancer, patients in whom long-term acid antisecretory therapy or long-term nonsteroidal anti-inflammatory drug therapy (including low-dose aspirin) is planned, and finally those who desire testing. Population screening among asymptomatic individuals with a high risk of gastric cancer, such as Korean- and Japanese-Americans, appears logical, but from a public health perspective should be done as a component of controlled intervention studies. There are no known H. pylori infections without risk of a symptomatic outcome, therefore screening represents a rational strategy for cancer prevention. Adoption of such a policy will require carefully balancing the costs of the programme with its benefits.

Infection à Helicobacter pylori et résistance aux antibiotiques

PURPOSE

Seven days triple therapies combining a proton pump inhibitor (PPI) and 2 antimicrobial agents (clarithromycin [C], amoxicillin [A], metronidazole [M]), are recommended for the treatment of Helicobacter pylori infection. The eradication failures have increased these last years, particularly in France (about 30%). They are essentially related to the development of antimicrobial agents resistance, mainly concerning macrolides and nitro-imidazoles.

CURRENT KNOWLEDGE AND KEY POINTS

Primary resistance to clarithromycin is variable, but reaching now about 10% throughout the world and about 20% in France. It reduces the eradication success rate at 25%. The secondary resistance is very high, contra-indicating the use of clarithromycin in second line regimens. Primary resistance to amoxicillin has recently appeared, but remains very low until now, less than 2%, as the tetracyclin (T) resistance. Primary resistance to metronidazole is 3 times higher than macrolides resistance, but its determination is less accurate. Metronidazole resistance reduces eradication rate of about 25%, leading to the use of metronidazole in second line therapy, in increasing the triple therapy duration at 14 days (PPI-A-M), or in combination with quadruple therapy (Bismuth-PPI-T-M). Other rescue-treatments are efficacious, based on ranitidine bismuth citrate combined regimens or on rifabutine (R) based regimens (PPI-A-R).

FUTURE PROSPECTS AND PROJECTS

The recent knowledge of the mutations mainly responsible for H. pylori resistance to antimicrobial agents now allows the development of detection methods based on the study of bacterial DNA. These methods have been validated for clarithromycin and should favour in the near future the determination of resistance by the use of biopsy culture or directly on the gastric biopsy.

Helicobacter pylori infection in pediatrics

A high prevalence and early colonization of Helicobacter pylori infection in childhood was described again this year in developing countries in contrast to developed ones. Upper gastrointestinal endoscopy including gastric biopsies remains the diagnostic gold standard method for this infection. Also noninvasive tests have been studied in children, including serology, 13C-urea breath test and stool antigen test, showing good results in the different age groups as compared to the gold standard. However, the infection often remains asymptomatic in children and the role of this bacterium in gastric manifestations is the subject of conflicting reports. Extra-digestive manifestations are also reported in the course of this infection. The treatment of H. pylori infection is influenced by resistance of the bacteria to the antibiotics used. We suggest that eradication of H. pylori should take place only after susceptibility testing. The association of a proton pump inhibitor and two antibiotics for 1 or 2 weeks gives the best eradication rates. The crucial question to elucidate is whether asymptomatic children should be treated to prevent cancer in the future.

Helicobacter pylori: a microbiologist's view

Helicobacter pylori infection is known to cause a number of gastrointestinal diseases. From the standpoint of a microbiologist there are several important facets to this organism, which include the nature of the organism, it's diagnosis and the effectiveness of eradication therapy.

Helicobacter in the developing world

Helicobacter pylori in the developing world is associated with many unique challenges not encountered in an industrialized setting. The 20% prevalence of infection with H. pylori among adolescents in the United States pales in comparison to infection rates exceeding 90% by 5 years of age in parts of the developing world. While H. pylori within the developed world is associated with gastritis, which may lead to peptic ulcer and gastric carcinoma, the infection in the developing world appears to also be linked with chronic diarrhea, malnutrition and growth faltering as well as predisposition to other enteric infections, including typhoid fever and cholera. Once identified, treatment of H. pylori within the developing world presents increased difficulties due to the frequency of antibiotic resistance as well as the frequency of recurrence after successful treatment. Control, and possibly eradication, of H. pylori could likely be achieved through increased standards of living and improved public health, as it has in the industrialized world. However, these measures are distant objectives for most developing countries, making long-term control of the organism dependent on the development and administration of an effective vaccine.

Is antimicrobial susceptibility testing necessary before second-line treatment for Helicobacter pylori infection?

BACKGROUND

An antimicrobial susceptibility test for Helicobacter pylori before second-line treatment is often performed, although whether the test is truly necessary remains unknown.

PATIENTS AND METHODS

Eighty-two patients with H. pylori infection for whom first-line treatment with a 1-week proton pump inhibitor/amoxicillin-clarithromycin (AC) regimen had failed were randomly assigned to two groups: those having or not having the susceptibility test before re-treatment. The cure rates for these two groups were compared.

RESULTS

Five of the 82 patients were excluded from the analysis. For 38 patients in the susceptibility-test group, we used what we considered the best regimen based on susceptibility testing: 10 patients [no resistance to clarithromycin (CAM)] received the lansoprazole-amoxicillin-clarithromycin regimen, 22 patients [19 CAM resistant, metronidazole (MNZ) susceptible; three failure of culture] were given the lansoprazole-amoxicillin-metronidazole (LAM) regimen, and six patients (both MNZ and CAM resistant) received dual therapy with omeprazole (OPZ) and amoxicillin (AMOX) in which the OPZ dose was determined by the CYP2C19 gene polymorphism. For 39 patients in the group with no susceptibility testing, LAM regimens were prescribed. The intention-to-treat (ITT)-based cure rates in the groups with and without susceptibility testing were 81.6% (95% confidence interval; 66-92%) and 92.4% (79-98%), respectively, and there was no significant difference between these two groups.

CONCLUSION

Susceptibility testing is not necessarily required before second-line therapy if the first-line treatment has been performed using proton pump inhibitor/AC regimens.