Antibiotic resistance problems with Helicobacter pylori

Combinations of antibiotics and vonoprazan for the treatment of Helicobacter pylori infections-Exploratory study

BACKGROUND

Vonoprazan fumarate is a novel potassium-competitive acid blocker more effective in suppressing acid production than proton pump inhibitors (PPIs) and when combined with antibiotics has been used to eradicate Helicobacter pylori (H. pylori) infection. However, it has not yet been examined in an Australian setting. This study aimed to report on the efficacy and safety of vonoprazan-containing antibiotic combination therapies in the eradication of H. pylori.

METHODS

A single-center, exploratory, clinical review of patients 18 years or over, positive for H. pylori on Urea Breath Test (UBT), and/or histopathology who underwent a 10-day treatment of combination antibiotics plus vonoprazan between January 2017 and September 2019 was conducted. Eleven different combinations of antibiotics that included 2-5 different antibiotics predominantly amoxicillin, rifabutin, levofloxacin, furazolidone, nitazoxanide, and tetracycline were included. The eradication success was based on negative UBT results and/or histopathology results after the treatment. Descriptive statistics were summarized.

RESULTS

One hundred and fifty-three patients (Female n = 74, 48%) with a positive for H. pylori were treated with vonoprazan-containing antibiotic combination therapy during the study period. Of the 153 patients, 48 (31%) had previously failed a PPI-based H. pylori treatment. Follow-up was available for 66/153 (43%) patients. In those who completed follow-up, overall eradication was achieved in 97% (64/66) of patients. In the subgroup of patients treated for the first time, eradication was achieved in 100% (44/44). In those who had failed prior, non-vonoprazan-containing treatment, eradication was achieved in 91% (20/22) of patients.

CONCLUSIONS

Vonoprazan-containing antibiotic therapy is an effective H. pylori eradication treatment. It is capable of achieving 100% efficacy in patients treated for the first time and even 91% efficacy in patients with previous eradication failure. Subsequent studies utilizing a factorial design will be needed to optimize each regimen as most regimens contained more than two antibiotics.

Influence of adding vitamin D3 to standard clarithromycin-based triple therapy on the eradication rates of Helicobacter pylori infection

BACKGROUND AND STUDY AIMS

The successful eradication rates with standard clarithromycin-based triple therapy are declining concerning the high antibiotic resistance rate and adverse drug reactions. This study aims to evaluate the effect of adding 1,25-hydroxyvitamin D3 on the eradication rates of the standard clarithromycin-based triple therapy for Helicobacter pylori infection.

PATIENTS AND METHODS

This is a randomized prospective comparative study of 150 patients diagnosed with H. pylori gastritis using magnifying narrow-band imaging endoscopy and supported by a stool antigen test. Patients were divided into two groups: group A (n = 75) treated with amoxicillin, clarithromycin, and esomeprazole for 2 weeks; group B (n = 75) treated with 1,25-hydroxyvitamin D3 for 1 month plus amoxicillin, clarithromycin, and esomeprazole for 2 weeks. The H. pylori eradication rates were assessed using stool antigen test conducted 4 weeks after the end of therapy. Furthermore, the H. pylori eradication rates were assessed with per-protocol (PP) and intention-to-treat (ITT) analyses.

RESULTS

The current results showed that H. pylori eradication was achieved in 46 of 62 (74.19%) and 46 of 75 (61.33%) patients via PP and ITT analyses, respectively, in group A. However, eradication was achieved in 60 of 68 (88.23%) and 60 of 75 (80%) patients via PP and ITT analyses, respectively, in group B. Therefore, the H. pylori eradication rates in the group where vitamin D3 was added to the clarithromycin-based triple therapy were significantly higher than in the other groups (p = 0.012 and p = 0.029 in ITT and PP analyses, respectively).

CONCLUSIONS

Adding vitamin D3 to the standard clarithromycin-based triple therapy could provide an additional advantage to achieve significantly higher eradication rates for H. pylori infection.

Adding Bismuth to Rabeprazole-Based First-Line Triple Therapy Does Not Improve the Eradication of Helicobacter pylori

This randomized controlled study aimed to evaluate whether adding bismuth to the standard first-line triple therapy could improve the eradication rate of Helicobacter pylori. A total of 162 patients with Helicobacter pylori infection were randomly assigned to either the 7-day triple therapy group (RAK regimen: rabeprazole 20 mg, amoxicillin 1 g, and clarithromycin 500 mg bid; n = 81) or the bismuth plus triple therapy group (n = 81). In the RBAK group, bismuth subcitrate 360 mg twice daily was added to the RAK regimen. A follow-up endoscopy or urea breath test was performed at least 4 weeks after eradication to confirm the treatment efficacy. Comparable compliance and Helicobacter pylori eradication rates were observed in both groups in either intention-to-treat [RAK 72.8% (59/81) versus RBAK 77.8% (63/81); p = 0.47] or per protocol analysis [RAK 74.7% (59/79) versus RBAK 81.8% (63/77); p = 0.26]. Adverse effects were commonly reported (50.6% for both groups) although most of these did not cause cessation of treatment. The resistance rate was 27.2% for metronidazole and 12.3% for clarithromycin. Adding bismuth to the standard 7-day triple therapy did not substantially increase the eradication rate. Further study is needed clarifying whether extending the duration of RBAK regimen to 10–14 days can lead to a better result.

Importance of antimicrobial susceptibility testing for the management of eradication in Helicobacter pylori infection

The management of Helicobacter pylori (H. pylori) infection treatment differs from the common treatment protocol for other infectious diseases. Because culture- or molecular-guided approaches face several practical issues, such as the invasive procedures required to obtain gastric biopsy specimens and the lack of availability of routine laboratory testing in some places, H. pylori treatment includes the administration of two or three empirically selected antibiotics combined with a proton pump inhibitor rather than evidence-based eradication treatment. The efficacy of empirical therapy is decreasing, mostly due to increasing multiple resistance. Multiresistance to levofloxacin, clarithromycin, and metronidazole, which are commonly used in empirical treatments, appears to have increased in many countries. Mutations play a primary role in the antimicrobial resistance of H. pylori, but many different mechanisms can be involved in the development of antibiotic resistance. Determining and understanding these possible mechanisms might allow the development of new methods for the detection of H. pylori and the determination of antimicrobial resistance. A treatment based on the detection of antimicrobial resistance is usually more effective than empirical treatment. Nevertheless, such an approach before treatment is still not recommended in the Maastricht guidelines due to the difficulty associated with the routine application of available culture- or molecular-based susceptibility tests, which are usually administered in cases of treatment failure. The management of first and rescue treatments requires further research due to the steadily increase in antimicrobial resistance.

Clinical significance of various diagnostic techniques and emerging antimicrobial resistance pattern of Helicobacter Pylori from Gastric Biopsy Samples

BACKGROUND

There is no single technique that can meet the criteria in identification of Helicobacter pylori. The diagnosis is important asantimicrobial resistance is frequently observed and associated with treatment failure. The present study was conducted to evaluate diagnostic tests for identification of H pylori and to assess their antimicrobial resistance pattern.

MATERIALS AND METHODS

Biopsies of gastric tissue from 200 patients with disorders of the upper gastrointestinal tract were studied for detection of H pylori by various methods like culture, H and E staining and urease test. Antimicrobial susceptibility testing was carried out by Kirby Bauer's disc diffusion method.

RESULTS

Out of 200 patients, H pylori was detected by rapid urease test, H and E staining and culture in 26.5%, 14.5% and 2.5% cases respectively. H and E was taken as the gold standard. Sensitivity of urease test was 76.6% and of culture 13.3%. Specificity of urease was 81.7% in comparison with culture which showed 99.4% specificity. Metronidazole (05) showed high level of resistance followed by amoxicillin (03) and norfloxacillin (03). Tetracycline, erythromycin, levofloxacin and cotrimoxazole showed one resistance each to H pylori.

CONCLUSION

H and E is taken as the gold standard according to CDC. Urease test is a better screening procedure than culture. H pylori resistance to metronidazole in our zone was highest. This is due to general and extensive use of metronidazole for other infectious diseases. Our study suggests need for a systematic approach to determine antibiogram of the strains before considering the drug regimens.

Comparison of the efficacy of culture-based tailored therapy for Helicobacter pylori eradication with that of the traditional second-line rescue therapy in Korean patients: a prospective single tertiary center study

OBJECTIVE

The effectiveness of Helicobacter pylori therapies has declined with an increase in antibiotic resistance. To overcome this problem, the efficacy of tailored H. pylori eradication therapy based on antimicrobial susceptibility testing was compared with that of empirical second-line rescue regimens.

MATERIAL AND METHODS

Patients who had persistent H. pylori infection after the first eradication were recommended to undergo culture for determining the minimal inhibitory concentration (MIC) via gastroscopy, which increased the cost by 300%. Fourteen-day esomeprazole, tripotassium dicitrate bismuthate, metronidazole and tetracycline (EBMT) therapy or esomeprazole, moxifloxacin and amoxicillin (MEA) therapy was performed according to the results of antibiotic susceptibility testing. In case of refusal to undergo culture, the participants were treated with either 14-day empirical EBMT or MEA regimen for second eradication after explaining the complexity, side effects and costs associated with each regimen. This trial was registered at ClinicalTrials.Gov (NCT 02349685).

RESULTS

In the 219 patients included, the intention to treat (ITT) and per protocol (PP) eradication rates was 75.3% and 79.8% in the 14-day EBMT group (n = 89), 70.8% and 72.4% in the 14-day MEA group (n = 89) and 87.8% and 100.0% in the 14-day tailored therapy group (n = 41), respectively. Based on the PP analysis, the 14-day tailored therapy group showed a significantly higher eradication rate than the 14-day EBMT or MEA group (both p ≤ 0.001).

CONCLUSIONS

Tailored therapy based on H. pylori culture and MIC test could be an option as a second-line eradication regimen in the presence of high level of antimicrobial resistance.

Antimicrobial resistance and characteristics of eradication therapy of Helicobacter pylori in Japan: a multi-generational comparison

BACKGROUND

Eradication of Helicobacter pylori (H. pylori) at a younger age is considered to be effective in preventing gastric cancer. This study assessed the characteristics of eradication therapy in young patients.

MATERIALS AND METHODS

We enrolled 1073 patients with H. pylori infection between 2000 and 2013. The subjects were divided into three groups according to age into the young (≤30 years), middle-aged (31-50 years), and elder (≥51 years) groups. We also examined 472 cases to investigate clinical eradication characteristics.

RESULTS

The rate of clarithromycin (CAM) resistance was 57.9%, 34.5%, and 35.2% in the young, middle-aged, and elder group, respectively, in 2012-2013 and was significantly higher in the young group than in the elder group (p = .01). Metronidazole (MNZ) resistance was similar among the three groups at each time point. While CAM resistance rose over the study period, MNZ resistance was noted to have decreased of late. The overall initial eradication success rate was 91.9% (95% CI, 89.1-94.1) in our cohort. Eradication efficiency was comparable in the young, middle-aged, and elder group at 94.3% (95% CI, 87.4-97.5), 90.2% (95% CI, 82.9-94.6), and 91.8% (95% CI, 88.1-94.5) respectively. Side effects such as skin rash were observed in 14.8%, 3.9%, and 3.5% of the respective groups. There were significant differences in the incidence of side effects between the young group and other groups (p < .05, respectively).

CONCLUSION

Since CAM resistance and the incidence of side effects are higher in young individuals, it is especially important to select eradication regimens based on testing for antimicrobial susceptibility.

Anti-ulcer activity of essential oil constituents

Essential oils have attracted considerable worldwide attention over the last few decades. These natural products have wide-ranging pharmacological activities and biotechnological applications. Faced with the need to find new anti-ulcer agents and the great effort on the development of drugs for the treatment of ulcers, in this review, the anti-ulcer activities of 21 bioactive compounds found in essential oils are discussed.

Comparison of azithromycin and clarithromycin triple therapy regimens for helicobacter pylori eradication in hemodialysis patients

Background

Helicobacter pylori eradication with clarithromycin is more expensive than with azithromycin.

Objectives

This study aimed to compare the effectiveness of these two antibiotics in eradicating H. pylori in hemodialysis (HD) patients.

Patients and Methods

This is a prospective, randomized, double-blinded clinical trial analysis of HD patients. Patients who had dyspepsia and showed positive results for two of three tests, anti-H. pylori serology, H. pylori stool antigen (HpSAg), or Urease Breath Test (UBT), were included in the study. The subjects consisted of 39 dialysis patients who were randomly divided into two groups that received medication twice daily. Group OAC received 20 mg omeprazol, 500 mg amoxycilin, and 250 mg clarithromycin, and Group OAAz received 20 mg omeprazol, 500 mg amoxicillin, and 250 mg azithromycin. Both regimens were administered for 14 days. Eradication was investigated by performing the UBT and the HpSAg test eight weeks later.

Results

This study began with 39 patients, 37 of which completed the treatment schedule (20 males and 17 females, mean age 59 years). Two patients died due to MI before beginning treatment. In the OAC group, negative results on the UBT and HpSAg tests were found in 82.4% and 88.2% of the participants, respectively. In the OAAz group, these values were 80% and 85%, respectively. The data showed that the difference between the two regimens was not significant (P = 1.0).

Conclusions

According to the data, no differences in eradication rates were apparent between the azitromycin and the claritromycin regimens. However, lower cost and fewer complaints could be considered as an advantage of the triple therapy with azithromycin.

The status of antimicrobial resistance of Helicobacter pylori in Eastern Azerbaijan, Iran: comparative study according to demographics

Helicobacter pylori-associated infections are extremely common in Iran, but few data about antibiotic sensitivity of H. pylori are available for this region. The purpose of this study was to investigate the prevalence of resistance in isolates against commonly used antibiotics in Eastern Azerbaijan, Iran, and the dependence of prevalence on the sex and age of patients. H. pylori isolates were collected by culture from gastric biopsies. Antibiotic susceptibility of isolates was determined by use of the disk agar diffusion test, and the minimum inhibitory concentration of clarithromycin was established by use of the Etest. A total 395 of biopsy specimens were studied; 112 samples of H. pylori were isolated (28.3 %), 55 (49 %) from males and 57 (51 %) from females. The prevalence of resistance to clarithromycin, metronidazole, erythromycin, amoxicillin, ciprofloxacin, rifampin, nitrofurantoin, and tetracycline were 16 (14.3 %), 86 (76.8 %), 29 (26.0 %), 32 (28.6 %), 37 (33.0 %), 32 (28.6 %), 13 (11.6 %), and 21 (18.7 %), respectively. Antimicrobial resistance was not statistically significantly associated with sex or age. Furthermore, the prevalence of resistance to metronidazole was high and that to clarithromycin was reasonable, consistent with reported low success in H. pylori treatment in this area. Therefore, continuous surveillance of antibiotic resistance of H. pylori is essential.

Alkyl hydroperoxide reductase: a candidate Helicobacter pylori vaccine

Helicobacter pylori (H. pylori) is the most important etiological agent of chronic active gastritis, peptic ulcer disease and gastric cancer. The aim of this study was to evaluate the efficacy of alkyl hydroperoxide reductase (AhpC) and mannosylated AhpC (mAhpC) as candidate vaccines in the C57BL/6J mouse model of H. pylori infection. Recombinant AhpC was cloned, over-expressed and purified in an unmodified form and was also engineered to incorporate N and C-terminal mannose residues when expressed in the yeast Pichia pastoris. Mice were immunized systemically and mucosally with AhpC and systemically with mAhpC prior to challenge with H. pylori. Serum IgG responses to AhpC were determined and quantitative culture was used to determine the efficacy of vaccination strategies. Systemic prophylactic immunization with AhpC/alum and mAhpC/alum conferred protection against infection in 55% and 77.3% of mice, respectively. Mucosal immunization with AhpC/cholera toxin did not protect against infection and elicited low levels of serum IgG in comparison with systemic immunization. These data support the use of AhpC as a potential vaccine candidate against H. pylori infection.

Lansoprazole-based sequential and concomitant therapy for the first-line Helicobacter pylori eradication

OBJECTIVE

The aim of this prospective study was to compare the efficacy of the first-line lansoprazole-based sequential therapy and concomitant therapy (lansoprazole, amoxicillin, clarithromycin and metronidazole) for Helicobacter pylori (H. pylori) eradication.

METHODS

A total of 169 patients with H. pylori infection were randomly assigned to either the sequential therapy group (n = 85) or the concomitant therapy group (n = 84). A follow-up endoscopy or urea breath test was examined at least 12 weeks after eradication.

RESULTS

Comparable H. pylori eradication rate was observed in both the sequential therapy and concomitant therapy groups by either intention-to-treat analysis [sequential 80.0% (68/85) vs concomitant 88.1% (74/84); P = 0.27] or per protocol analysis [sequential, 85.3% (64/75) vs concomitant, 94.6% (70/74); P = 0.60]. Adverse effects were reported and good compliance was observed in both groups (P = 0.72). Although dual antibiotics resistance affected the therapeutic efficacy of sequential therapy (P = 0.03), not concomitant therapy (P = 0.74), it was not an independent factor for predicting the treatment outcome.

CONCLUSION

First-line lansoprazole-based sequential and concomitant therapy were well-tolerated and comparable in terms of their H. pylori eradication rate.

Characterisation of the genes encoding resistance to metronidazole (rdxA and frxA) and clarithromycin (the 23S-rRNA genes) in South African isolates of Helicobacter pylori

Helicobacter pylori has been incriminated in human diseases, such as peptic ulcer, gastritis and gastric malignancy. Although modern triple-drug regimens are usually highly effective in the treatment of H. pylori infection, the emergence of resistance to two of the most used antibiotics, metronidazole (Mtz) and clarithromycin (Cla), is a serious and increasing problem. Truncations in the rdxA and frxA genes of H. pylori are thought to be associated with Mtz resistance whereas mutations in the pathogen's 23S-ribosomal-RNA (23S-rRNA) genes are associated with Cla resistance. In a recent study, PCR and sequence analysis of the rdxA, frxA and 23S-rRNA genes were used to explore the genetic basis of resistance to Mtz and Cla in H. pylori. When 200 isolates of H. pylori from the Eastern Cape province of South Africa were tested for antibiotic susceptibility, almost all (95·5%) were found resistant to Mtz and 20·0% were found resistant to Cla. Only the Mtz-resistant isolates showed rdxA and frxA truncation. Two point mutations were detected in the 23S-rRNA genes of the Cla-resistant isolates. Many significant changes (resulting in 13 amino-acid substitutions in nine loci and truncated proteins in 14 loci) were observed in the rdxA genes of the Mtz-resistant isolates, and it appears that, compared with the rarer changes detected in frxA, such mutations may contribute more significantly to the high prevalence of Mtz resistance. To guide empiric treatment, the genotypes and antibiotic susceptibility of H. pylori in the Eastern Cape province of South Africa need to be monitored regularly.

Correlation between creatinine clearance and Helicobacter pylori infection eradication with sequential and triple therapeutic regimens: A randomised clinical trial

BACKGROUND AND STUDY AIMS

Uraemic patients show susceptibility to gastrointestinal mucosal lesions and colonisation by Helicobacter pylori (HP). Antibiotic resistance constitutes a problem in treatment and bismuth preparations are toxic in uraemic patients. This study aimed to assess the correlation between creatinine clearance (CrCl) and eradication of HP infection with new sequential and standard triple therapeutic regimens.

PATIENTS AND METHODS

A total of 120 HP-positive patients with renal function impairment and 60 control patients with HP infection were enrolled in this study. Patients were divided into four groups on the basis of CrCl and were randomly assigned to one of the two different regimens: A 14-day standard triple therapy with 20mg omeprazole bid, 1000mg amoxicillin bid and 500mg clarithromycin bid and a new sequential regimen with 20mg omeprazole bid and 1000mg amoxicillin bid both for 14 days, 500mg ciprofloxacin bid for the first 7 days and 200mg furazolidone bid for the last 7 days. Doses of amoxicillin, clarithromycin and ciprofloxacin were reduced to 50% in the cases of CrCl <30mgdl(-1).

RESULTS

One hundred and sixty two out of 180 HP-positive patients (54.3% male, 51.6±12.1 years) completed treatment in the four groups and were studied. According to renal function they were classified into group A (n=39), haemodialysis (HD) patients; group B (n=37), CrCl <30mgdl(-1) without HD; group C (n=36), CrCl between 30 and 60mgdl(-1); and group D (n=50), control subjects with CrCl >90mgdl(-1). HP was successfully eradicated in 77.7% of patients with standard triple therapy and in 81.4% of patients with the sequential therapy. There was no significant difference among the study groups in the rate of HP-infection eradication with both regimens.

CONCLUSION

HP eradication rates did not differ with both sequential and standard therapeutic regimens in uraemic and non-uraemic patients. We, therefore, prefer the standard triple therapy due to its simplicity and reported.

Antibiotic susceptibility profile of Helicobacter pylori isolated from the dyspepsia patients in Tehran, Iran

BACKGROUND/AIM

Helicobacter pylori is an important pathogen for gastroduodenal diseases. Infection with H. pylori can be limited by regimens of multiple antimicrobial agents. However, antibiotic resistance is a leading cause of treatment failure. The aim of this study has been to determine the resistance patterns of H. pylori strains isolated from gastric biopsies of patients with dyspepsia by agar dilution method, in Tehran, Iran.

PATIENTS AND METHODS

H. pylori isolates from patients with gastrointestinal diseases were evaluated for susceptibility testing by agar dilution method. Susceptibility testing was performed to commonly used antibiotics including clarithromycin, tetracycline, amoxicillin, metronidazole and ciprofloxacin.

RESULTS

Among 92 patients with dyspepsia, H. pylori strains were isolated from 42 patients. Seventeen (40.5%) of the isolates were resistant to metronidazole (MICs ≥ 8 μg/l), whereas one isolate (2.4%) was resistant to amoxicillin (MICs ≤ 0. 5 μg/ml) and ciprofloxacin (MICs ≤ 1μg/ml). The resistance rates to other antibiotics in H. pylori isolates are recorded as follows: clarithromycin 6 (14.3 %), tetracycline 2 (4.8%). In 5 of 42 resistant cases, combined resistance was found.

CONCLUSIONS

These data suggest that metronidazole should be used among Iranian patients in first-line therapy with caution, and ciprofloxacin in association with amoxicillin and a proton pump inhibitor is more recommended.

High frequency of A2143G mutation in clarithromycin-resistant Helicobacter pylori isolates recovered from dyspeptic patients in Iran

BACKGROUND/AIM

Resistance to clarithromycin in H. pylori isolates is accepted as a main cause of treatment failure in developing countries. We aimed to determine the prevalence of clarithromycin-resistant strains isolated from dyspeptic patients in northern Iran, furthermore we aimed to assess the relationship between clinical outcomes of infection with point mutations.

MATERIALS AND METHODS

A total of 147 consecutive patients infected with H. pylori were included for determining the status of resistant H. pylori strains. With upper gastroscopy, three antral biopsies were taken from each patient, first section for rapid urea test, second for pathology and third section was used for bacterial culture in microbiologic lab. The antimicrobial susceptibility tests in this examination were agar dilution, in accordance with clinical and laboratory standards institue guidelines. Restriction fragment length polymorphism-PCR (RFLP-PCR) method was applied to determine the frequency of point mutations in 23s rRNA gene. Statistical analysis was performed using SPSS software (15.0) (SPSS, Inc., Chicago, Ill). Chi-square and Fisher's exact tests were applied to our analysis. A P value less than 5% was considered as statistically significant.

RESULTS

Our results showed that there was no point mutation in clarithromycin-susceptible strains of H. pylori.

CONCLUSION

The important findings in our study indicate that A2143G is the most prevalent point mutation (30/32: 93.7%) attributed in clarithromycin resistance among the H. pylori strains. The current study concluded that clarithromycin could still be involved in the empirical treatment of H. pylori infection, although a high frequency of A2143G mutation may increase the concerns regarding treatment failure.

The bifidogenic growth stimulator inhibits the growth and respiration of Helicobacter pylori

BACKGROUND

Triple therapy with amoxicillin, clarithromycin, and a proton-pump inhibitor is a common therapeutic strategy for the eradication of Helicobacter pylori (H. pylori). However, frequent appearance of clarithromycin-resistant strains is a therapeutic challenge. While various quinones are known to specifically inhibit the growth of H. pylori, the quinone 1,4-dihydroxy-2-naphthoic acid (DHNA) produced by Propionibacterium has strong stimulating effect on Bifidobacterium. We were interested to see whether DHNA could inhibit the growth of H. pylori in in vitro or in vivo experimental setting.

MATERIALS AND METHODS

The minimum inhibitory concentration (MIC) of DHNA was determined by the agar dilution method. The inhibitory action of DHNA on the respiratory activity was measured by using an oxygen electrode. Germ-free mice infected with H. pylori were given DHNA in free drinking water containing 100 μg/mL for 7 days.

RESULTS

DHNA inhibited H. pylori growth at low MIC values, 1.6-3.2 μg/mL. Likewise, DHNA inhibited clinical isolates of H. pylori, resistant to clarithromycin. However, DHNA did not inhibit other Gram negative or anaerobic bacteria in the normal flora of the human intestine. Both H. pylori cellular respiration and adenosine 5'-triphosphate (ATP) generation were dose-dependently inhibited by DHNA. Similarly, the culture filtrates of propionibacterial strains inhibited the growth of H. pylori, and oral administration of DHNA could eradicate H. pylori in the infected germ-free mice.

CONCLUSIONS

The bifidogenic growth stimulator DHNA specifically inhibited the growth of H. pylori including clarithromycin-resistant strains in vitro and its colonization activity in vivo. The bactericidal activity of DHNA was via inhibition of cellular respiration. These actions of DHNA may have clinical relevance in the eradication of H. pylori.

An African perspective on Helicobacter pylori: prevalence of human infection, drug resistance, and alternative approaches to treatment

Helicobacter pylori is a Gram-negative, micro-aerophilic, motile, curved rod that inhabits the gastric mucosa of the human stomach. It chronically infects thousands of millions of people world-wide, and is one of the most genetically diverse of bacterial species. Infection with the bacterium leads to chronic gastritis, peptic ulceration, gastric cancers and gastric mucosa-associated lymphoid-tissue (MALT) lymphoma. The prevalence of infection appears to be partly determined by geographical and socio-demographic factors, being higher in Africa than elsewhere. Current treatment, based on potent combinations that each consist of a proton-pump inhibitor and two antibiotics, is successful in 80%-90% of patients. Some undesirable side-effects, poor patient compliance and drug resistance are, however, associated with significant levels of treatment failure and with contra-indications for some patients. Antibiotic resistance in H. pylori is a growing global concern that merits the urgent attention of public-health authorities. Numerous pieces of clinical evidence have revealed that eradication of the organism from a patient results in improvement of gastritis and drastically decreases the frequency of relapse of gastric and duodenal ulcers. Natural products, including medicinal plants and honey, may offer useful alternatives in the treatment of H. pylori-related infections.

Sequential and concomitant therapy with four drugs is equally effective for eradication of H pylori infection

BACKGROUND & AIMS

Sequential therapy with a proton pump inhibitor (PPI) and amoxicillin followed by a PPI, clarithromycin, and an imidazole agent reportedly have a better rate of curing Helicobacter pylori infection than PPI, amoxicillin, and clarithromycin triple therapy. The concomitant administration of these 4 drugs (concomitant therapy) is also an effective treatment strategy. We compared the efficacies of sequential and concomitant therapy and analyzed the effects of antibiotic resistance in patients with H pylori infection.

METHODS

In a randomized trial of 232 H pylori-infected patients from 3 hospitals in Kaohsiung, Taiwan, patients were given 10 days of sequential (n = 115) or concomitant (n = 117) therapy. H pylori status was confirmed by endoscopy or urea breath test.

RESULTS

Intention-to-treat analysis demonstrated similar eradication rates for sequential (92.3%; 95% confidence interval [CI], 87.5%-97.1%) and concomitant therapy (93.0%; 95% CI, 88.3%-97.7%)(P = .83). Per-protocol eradication results were similar for sequential (93.1%; 95% CI, 90.7%-95.5%) and concomitant therapy (93.0%; 95% CI, 88.3%-97.7%) (P = .99). Univariate analysis showed that compliance and resistance to clarithromycin were independent determinants of eradication. Dual resistance did not influence the level of eradication in the concomitant group, but significantly affected that of the sequential therapy group. Clarithromycin resistance was less frequent than expected.

CONCLUSIONS

Sequential or concomitant therapy with a PPI, amoxicillin, clarithromycin, and an imidazole agent are equally effective and safe for eradication of H pylori infection. Resistance to clarithromycin, compliance, and adverse events reduced the level of eradication. Concomitant therapy may be more suitable for patients with dual resistance to antibiotics.

In vitro anti-Helicobacter pylori activity of usnic acid

Eradication of Helicobacter pylori is an important objective in overcoming gastric diseases. Many regimens are currently available but none of them could achieve 100% success in eradication. Medicinal lichen is used in the treatment of gastric ulcer in local folk medicine in Anatolia (Turkey). The present study was performed to assess the in vitro effects of usnic acid from Usnea dasypoga against clinical isolates and standard H. pylori strains and their minimum inhibitory concentrations (MICs). A total of 38 strains was assayed for anti-H. pylori activity. The agar dilution method was used for the determination of usnic acid and clarithromycin resistance.Six (16.2%) clinical isolates were resistant to usnic acid and five (13.5%) were resistant to clarithromycin. Dual susceptibility to usnic acid and clarithromycin rate was detected as very high (97.3%). Usnic acid has a strong and dose-dependent activity against H. pylori strains. The synergism between usnic acid and clarithromycin may be effective in the treatment of H. pylori infection.

A redox basis for metronidazole resistance in Helicobacter pylori

Metronidazole resistance in Helicobacter pylori has been attributed to mutations in rdxA or frxA. Insufficient data correlating RdxA and/or FrxA with the resistant phenotype, and the emergence of resistant strains with no mutations in either rdxA or frxA, indicated that the molecular basis of H. pylori resistance to metronidazole required further characterization. The rdxA and frxA genes of four matched pairs of metronidazole-susceptible and -resistant strains were sequenced. The resistant strains had mutations in either rdxA, frxA, neither gene, or both genes. The reduction rates of five substrates suggested that metabolic differences between susceptible and resistant strains cannot be explained only by mutations in rdxA and/or frxA. A more global approach to understanding the resistance phenotype was taken by employing two-dimensional gel electrophoresis combined with tandem mass spectrometry analyses to identify proteins differentially expressed by the matched pair of strains with no mutations in rdxA or frxA. Proteins involved in the oxireduction of ferredoxin were downregulated in the resistant strain. Other redox enzymes, such as thioredoxin reductase, alkyl hydroperoxide reductase, and superoxide dismutase, showed a pI change in the resistant strain. The data suggested that metronidazole resistance involved more complex metabolic changes than specific gene mutations, and they provided evidence of a role for the intracellular redox potential in the development of resistance.

Antimicrobial activity of curcumin against Helicobacter pylori isolates from India and during infections in mice

Treatment failure is a major cause of concern for the Helicobacter pylori-related gastroduodenal diseases like gastritis, peptic ulcer, and gastric cancer. Curcumin, diferuloylmethane from turmeric, has recently been shown to arrest H. pylori growth. The antibacterial activity of curcumin against 65 clinical isolates of H. pylori in vitro and during protection against H. pylori infection in vivo was examined. The MIC of curcumin ranges from 5 microg/ml to 50 microg/ml, showing its effectiveness in inhibiting H. pylori growth in vitro irrespective of the genetic makeup of the strains. The nucleotide sequences of the aroE genes, encoding shikimate dehydrogenase, against which curcumin seems to act as a noncompetitive inhibitor, from H. pylori strains presenting differential curcumin MICs showed that curcumin-mediated growth inhibition of Indian H. pylori strains may not be always dependent on the shikimate pathway. The antimicrobial effect of curcumin in H. pylori-infected C57BL/6 mice and its efficacy in reducing the gastric damage due to infection were examined histologically. Curcumin showed immense therapeutic potential against H. pylori infection as it was highly effective in eradication of H. pylori from infected mice as well as in restoration of H. pylori-induced gastric damage. This study provides novel insights into the therapeutic effect of curcumin against H. pylori infection, suggesting its potential as an alternative therapy, and opens the way for further studies on identification of novel antimicrobial targets of curcumin.

In vitro susceptibility of Helicobacter pylori to extracts of Eucalyptus camaldulensis and Eucalyptus torelliana

The in vitro susceptibility of Helicobacter pylori to extracts of Eucalyptus camaldulensis Dehnh. and Eucalyptus torelliana F. Muell. (Myrtaceae), Nigerian medicinal plants, was investigated in six strains of H. pylori, namely, ATCC 4504, ATCC 47619, A2, TI8984, 019A, and A6. The susceptibility of these strains was determined using a standardized agar dilution method (National Committee for Clinical Laboratory Standards guidelines) with Mueller-Hinton agar, supplemented with defibrinated horse blood. The minimum inhibitory concentrations of the crude extracts against all the tested strains ranged from 12.5 to 400 mug/mL. Phytochemical screening of the plant extracts revealed the presence of tannins, saponins, and cardenolides. The anti-H. pylori activities demonstrated by these plants may be attributed to their chemical constituents, and explain their reported traditional uses, as well as their gastroprotective properties as demonstrated previously in experimental animals. The results of this work suggest that, in accordance with their traditional medical use in Nigeria, E. camaldalensis and E. torelliana have some therapeutic potential against H. pylori, and thus are of interest for the treatment of H. pylori infections.

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.

Systematic review and meta-analysis from Chinese literature: the association between Helicobacter pylori eradication and improvement of functional dyspepsia

OBJECTIVES

To evaluate the effect of eradicating Helicobacter pylori on dyspeptic symptoms in patients with functional dyspepsia in China.

DATA SOURCES

Randomized controlled trials conducted in China and those published between 1989 and April 2007.

REVIEW METHODS

The articles were retrieved from Chinese biomedicine Web database and Chinese scientific Journals database using proper MESH headings and assessed by two independent investigators according to established inclusion criteria. The characteristics of chosen articles were displayed for further analysis, and summary odds ratio were calculated to determine the overall effect of H. pylori eradication. All the data were entered and analyzed using REVIEW MANAGER 4.1, and p < .05 was defined as statistically significant in all analysis.

RESULTS

Seven qualified trials were enrolled, and the summary odds ratio for improvement in dyspeptic symptoms in patients with functional dyspepsia in whom H. pylori was eradicated was 3.61 (95%CI: 2.62, 4.98, p < .00001). The difference in the follow-up period did not influence the final outcomes.

CONCLUSIONS

An improvement in dyspeptic symptoms occurred among Chinese patients with functional dyspepsia in whom H. pylori was eradicated.

Identification of disulfide reductases in Campylobacterales: a bioinformatics investigation

Disulfide reductases of host-colonising bacteria are involved in the expression of virulence factors, resistance to drugs, and elimination of toxic compounds. Large-scale genome analyses of 281 prokaryotes identified CXXC and CXXC-derived motifs in each microorganism. The total number of these motifs showed correlations with genome size and oxygen tolerance of the prokaryotes. Specific bioinformatic analyses served to identify putative disulfide reductases in the Campylobacterales Campylobacter jejuni, Helicobacter pylori, Wolinella succinogenes and Arcobacter butzleri which colonise the gastrointestinal tract of higher animals. Three filters applied to the genomes of these species yielded 35, 25, 28 and 34 genes, respectively, encoding proteins with the characteristics of disulfide reductases. Ten proteins were common to the four species, including four belonging to the thioredoxin system. The presence of thioredoxin reductase activities was detected in the four bacterial species by observing dithiobis-2-nitrobenzoic acid reduction with beta-nicotinamide adenine dinucleotide phosphate as cofactor. Phylogenetic analyses of the thioredoxin reductases TrxB(1) and TrxB(2) of the four Campylobacterales were performed. Their TrxB(1) proteins were more closely related to those of Firmicutes than to the corresponding proteins of other Proteobacteria. The Campylobacterales TrxB(2) proteins were closer to glutathione reductases of other organisms than to their respective TrxB(1) proteins. The phylogenetic features of the Campylobacterales thioredoxin reductases suggested a special role for these enzymes in the physiology of these bacteria.

Alaska sentinel surveillance for antimicrobial resistance in Helicobacter pylori isolates from Alaska native persons, 1999-2003

BACKGROUND

Previous studies in Alaska have demonstrated elevated proportions of antimicrobial resistance among Helicobacter pylori isolates.

MATERIALS AND METHODS

We analyzed H. pylori data from the Centers for Disease Control and Prevention (CDC)'s sentinel surveillance in Alaska from July 1999 to June 2003 to determine the proportion of culture-positive biopsies from Alaska Native persons undergoing routine upper-endoscopy, and the susceptibility of H. pylori isolates to metronidazole [minimum inhibitory concentration (MIC) of > 8 g metronidazole/mL), clarithromycin (MIC > or = 1), tetracycline (MIC > or = 2) and amoxicillin (MIC > or = 1)] using agar dilution.

RESULTS

Nine-hundred sixty-four biopsy specimens were obtained from 687 participants; 352 (51%) patients tested culture positive. Mean age of both culture-positive and culture-negative patients was 51 years. Metronidazole resistance was demonstrated in isolates from 155 (44%) persons, clarithromycin resistance from 108 (31%) persons, amoxicillin resistance from 8 (2%) persons, and 0 for tetracycline resistance. Metronidazole and clarithromycin resistance varied by geographic region. Female patients were more likely than male subjects to show metronidazole resistance (p < .01) and clarithromycin resistance (p = .05).

CONCLUSIONS

Resistance to metronidazole and clarithromycin is more common among H. pylori isolates from Alaska Native persons when compared with those from elsewhere in the USA.

High prevalence and level of resistance to metronidazole, but lack of resistance to other antimicrobials in Helicobacter pylori, isolated from a multiracial population in Kuwait

BACKGROUND

The primary treatment regimen for Helicobacter pylori infection for Kuwaitis does not contain metronidazole, but that for expatriates does. There is also increasing failure of antimicrobial therapy.

AIM

To determine the susceptibility of H. pylori from upper gastrointestinal biopsies of Kuwaitis and non-Kuwaitis to find out if differences existed in the susceptibilities of the isolates from the two different populations.

METHODS

The susceptibilities of 96 H. pylori isolates were tested against metronidazole, amoxicillin, clarithromycin and tetracycline by the E test. The rdxA gene was analysed from selected metronidazole-susceptible and metronidazole-resistant strains to find out polymorphism and the basis of metronidazole resistance.

RESULTS

Approximately, 70% of isolates from both populations were metronidazole resistant with 65% isolates showing high minimum inhibitory concentration values of >256 mug/mL. No resistance to the other three antimicrobials was found. There were novel nonsense and missense mutations with no deletion in the rdxA gene by insertion of mini-IS605.

CONCLUSIONS

The prevalence and level of metronidazole resistance in H. pylori in the two populations was high with no difference, in spite of different treatment regimens. Metronidazole resistance in this transitional country appeared to be independent of prior metronidazole use for treatment of H. pylori infection.

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.

Azithromycin in one week quadruple therapy for H pylori eradication in Iran

AIM: To investigate eradication rates, patient compliance and tolerability of a 1-wk Azithromycin-based quadruple therapy versus the 2-wk conventional therapy.

METHODS: A total of 129 H pylori-positive patients were randomized to either omeprazole 20 mg, bismuth subcitrate 240 mg, azithromycin 250 mg, and metronidazole 500 mg, all twice daily for 1-wk (B-OAzM) or omeprazole 20 mg, bismuth subcitrate 240 mg, amoxicillin 1g, and metronidazole 500 mg all twice daily for 2-wk (B-OAM). H pylori infection was defined at entry by histology and rapid urease test and cure of infection was determined by negative urea breath test.

RESULTS: H pylori eradication rates produced by B-OAzM and B-OAM were 74.1% and 70.4% respectively based on an intention to treat analysis, and 78.1% versus 75.7% respectively based on a per-protocol analysis. The incidence of poor compliance was lower, although not significantly so, in patients randomized to B-OAzM than for B-OAM (3.5% versus 4.3%) but intolerability was similar in the two groups ( 35% versus 33.3%).

CONCLUSION: 1-wk azithromycin based quadruple regimen achieves an H pylori eradication rate comparable to that of standard 2-wk quadruple therapy, and is associated with comparable patient compliance and complications.

Maintenance therapy with H2-receptor antagonist until assessment of Helicobacter pylori eradication can reduce recurrence of peptic ulcer after successful eradication of the organism: prospective randomized controlled trial

PURPOSE

This study examined the possible relationship between peptic ulcer recurrence and the presence or absence of maintenance therapy with an H(2)-receptor antagonist performed until evaluation of Helicobacter pylori eradication.

METHODS

The subjects were 483 patients with peptic ulcer (281 gastric ulcer and 202 duodenal ulcer) who were diagnosed as H. pylori positive. After receiving eradication therapy for H. pylori, patients were allocated at random to one of three different maintenance therapies: control group (no maintenance therapy), H(2)-receptor antagonist half-dose group, and H(2)-receptor antagonist full-dose group. The maintenance therapy was performed for 4 weeks until evaluation of H. pylori eradication.

RESULTS

Among the 25 patients with a recurrent ulcer, 18 patients (72%) had a recurrence at the time of or before evaluation of H. pylori eradication. In the control group, the rate of ulcer recurrence occurring before evaluation of H. pylori eradication was 10.5% (14/133). This rate was significantly higher than those in the H(2)-receptor antagonist half-dose group (2.9%, 4/136) and the full-dose group (0%, 0/135).

CONCLUSION

The results of this study suggest that maintenance therapy with an H(2)-receptor antagonist performed after eradication therapy until evaluation of H. pylori eradication is likely to greatly reduce the ulcer recurrence rate without affecting evaluation of H. pylori eradication.

Effectiveness of minocycline-based triple therapy for eradication of Helicobacter pylori infection

BACKGROUND

Widespread use of eradication therapy for Helicobacter pylori has increased the prevalence of clarithromycin-resistant strains. The purpose of the present paper was to measure the in vitro antibacterial activity of minocycline against H. pylori, and study the effectiveness of minocycline-based first- and second-line eradication therapies.

METHODS

For first-line therapy, 79 patients were randomly assigned to the treatment with rabeprazole, amoxicillin, and clarithromycin or with rabeprazole, amoxicillin, and minocycline. For second-line therapy, 88 patients were tested for sensitivity to metronidazole: 67 patients with metronidazole-sensitive strains received a 7-day course of rabeprazole, minocycline, and metronidazole; the remaining 21 patients were given a 7-day course of rabeprazole, minocycline, and faropenem.

RESULTS

There was virtually no resistance to minocycline among the strains tested. The eradication rate of H. pylori infection in first-line therapy was significantly lower for minocycline-containing regimen (38.5%, 15/39) than for clarithromycin-containing regimen (82.5%, 33/40; P < 0.01). For second-line therapy, a high eradication rate against metronidazole-sensitive strains was obtained with rabeprazole, minocycline and metronidazole (85%, 57/67).

CONCLUSIONS

A combination of rabeprazole, minocycline, and metronidazole is safe and effective for second-line therapy of H. pylori infection. Because this regimen can be administered to patients with penicillin allergy and patients who suffer adverse reactions to amoxicillin, such as diarrhea and other digestive symptoms, it should be considered useful for second- and third-line eradication therapy.

Antimicrobial activities of Eugenol and Cinnamaldehyde against the human gastric pathogen Helicobacter pylori

BACKGROUND

Eradication of Helicobacter pylori is an important objective in overcoming gastric diseases. Many regimens are currently available but none of them could achieve 100% success in eradication. Eugenol and cinnamaldehyde that are commonly used in various food preparations are known to possess antimicrobial activity against a wide spectrum of bacteria.

AIM

The present study was performed to assess the in vitro effects of eugenol and cinnamaldehyde against indigenous and standard H. pylori strains, their minimum inhibitory concentrations (MICs) and time course lethal effects at various pH.

METHODS

A total of 31 strains (29 indigenous and one standard strain of H. pylori ATCC 26695, one strain of E. coli NCIM 2089) were screened. Agar dilution method was used for the determination of drug sensitivity patterns of isolates to the commonly used antibiotics and broth dilution method for the test compounds.

RESULTS

Eugenol and cinnamaldehyde inhibited the growth of all the 30 H. pylori strains tested, at a concentration of 2 mug/ml, in the 9th and 12th hours of incubation respectively. At acidic pH, increased activity was observed for both the compounds. Furthermore, the organism did not develop any resistance towards these compounds even after 10 passages grown at sub-inhibitory concentrations.

CONCLUSION

These results indicate that the two bioactive compounds we tested may prevent H. pylori growth in vitro, without acquiring any resistance.

Anti-Helicobacter pylori compounds from Santalum album

Six new sesquiterpenes, (Z)-2beta-hydroxy-14-hydro-beta-santalol (1), (Z)-2alpha-hydroxy-albumol (2), 2R-(Z)-campherene-2,13-diol (3), (Z)-campherene-2beta,13-diol (4), (Z)-7-hydroxynuciferol (5), and (Z)-1beta-hydroxy-2-hydrolanceol (6), together with five known compounds, (Z)-alpha-santalol (7), (Z)-beta-santalol (8), (Z)-lanceol (9), alpha-santaldiol (10), and beta-santaldiol (11), were isolated from Santalum album, by using bioassay-guided fractionation for Helicobacter pylori. The structures were determined by extensive NMR studies. The absolute configuration of compound 3 was determined by a modified Mosher method. The crude extracts as well as the isolated compounds showed antibacterial activity against H. pylori. Especially, compounds 7 and 8 have strong anti-H. pylori activities against a clarithromycin-resistant strain (TS281) as well as other strains.

Mutational analysis of metronidazole resistance in Helicobacter pylori

Metronidazole is one of a few antibiotics effective in eliminating Helicobacter pylori infection of the human stomach. Several chromosomal loci have been implicated in resistance to this drug. Saturation transposon mutagenesis of the H. pylori genome revealed inactivation of the rdxA gene as uniquely able to confer metronidazole resistance.

Helicobacter pyloridisulphide reductases: role in metronidazole reduction

Disulphide reductases play an important role in maintaining intracellular redox potential. Three disulphide reductase activities were identified in Helicobacter pylori, which used dithiobis-2-nitrobenzoic acid, glutathione or l-cystine and ferredoxin as substrates. The kinetic parameters of these activities were determined and it was demonstrated that the reductase activities were inhibited by the presence of metronidazole. Substrate competition experiments served to show inhibition of metronidazole reduction by dithiobis-2-nitrobenzoic acid, glutathione and ferredoxin in lysates from metronidazole susceptible and resistant matched pairs of strains. The study demonstrated that the activities of three disulphide reductases were modulated by the presence of metronidazole, and that metronidazole reduction was inhibited by the presence of disulphide reductase substrates.

One-year follow-up study of Helicobacter pylori eradication rate with 13C-urea breath test after 3-d and 7-d rabeprazole-based triple therapy

AIM: To investigate the long-term role of a 3-d rabeprazole-based triple therapy in patients with Helicobacter pylori(H pylori)-infected active peptic ulcers.

METHODS: We prospectively studied 115 consecutive patients with H pylori-infected active peptic ulcers. H pylori infection was confirmed if any two of H pylori DNA, histology, and rapid urease test were positive. Patients were assigned to either an open-labeled 3-d course of oral amoxicillin 1000 mg b.i.d., clarithromycin 500 mg b.i.d., and rabeprazole 20 mg b.i.d., or 7-d course of oral amoxicillin 1000 mg b.i.d., clarithromycin 500 mg b.i.d., and rabeprazole 20 mg b.i.d. Subsequently, all patients received oral rabeprazole 20 mg once daily until the 8^th wk. Three months after therapy, all patients were followed-up endoscopically for the peptic ulcer, H pylori DNA, histology, and rapid urease test. One year after therapy, H pylori infection was tested using the ¹³C-urea breath test.

RESULTS: The ulcer healing rates 3 mo after therapy were 81.0% vs 75.4% for the 3-d and 7-d groups [intention-to-treat (ITT) analysis, P = 0.47] respectively, and 90.4% vs 89.6% for the 3-d and 7-d groups [per-protocol (PP) analysis, P = 0.89] respectively. The eradication rates 3 mo after therapy were 75.9% vs 73.7% for the 3-d and 7-d groups (ITT, P = 0.79) respectively, and 84.6% vs 87.5% for the 3-d and 7-d groups (PP, P = 0.68) respectively. One year after therapy, seventy-five patients returned to receive the ¹³C-urea breath test, and the eradication rates were 78.4% vs 81.6% in 3-d and 7-d groups (PP, P = 0.73) respectively.

CONCLUSION: Our study showed the eradication rates against H pylori infection 3 and 12 mo after triple therapy were not different between the 3-d and 7-d rabeprazole-based groups. Therefore, the 3-d rabeprazole-based triple therapy may be an alternative treatment for peptic ulcers with H pylori infection.

Helicobacter pylori infection in hemodialysis patients: Susceptibility to amoxicillin and clarithromycin

AIM: To evaluate susceptibility of Helicobacter pylori to amoxicillin and clarithromycin in end-stage renal disease (ESRD) patients and non-uremic controls.

METHODS: The subjects with dyspeptic complaints were 33 ESRD patients and 46 age- and sex-matched non-uremic controls who exhibited H pylori on antral biopsy specimens. The two groups were age and sex matched. The H pylori strains’ pattern of susceptibility to amoxicillin and clarithromycin was investigated with the agar dilution technique.

RESULTS: None of the H pylori strains from either group showed resistance to amoxicillin with the agar dilution method. Twelve (36.4%) of the ESRD group strains and 7 (15.2%) of the control group strains showed resistance to clarithromycin, and this difference was statistically significant (P<0.05).

CONCLUSION: Resistance to amoxicillin does not appear to be an important problem in H pylori-infected ESRD and non-uremic patients in our region. In contrast, the rates of resistance to clarithromycin are high, particularly in the ESRD population.

Amoxicillin resistance in Helicobacter pylori: studies from Tokyo, Japan from 1985 to 2003

BACKGROUND

Previous reports revealed no resistant strains of amoxicillin (AMPC), which is usually used in eradication therapy for H. pylori infection. However, the frequency and evolution of natural AMPC-resistant strains in the Japanese population remains unknown.

AIM

To assess the prevalence of H. pylori resistance against AMPC in the Tokyo area, a collection of 648 H. pylori strains isolated from patients with GI diseases from 1985 to 2003 was tested for their sensitivity to AMPC.

METHODS

The susceptibility of the strains was assessed by determination of the minimal inhibitory concentration (MIC) using the E-test and/or the Dry-plate method. The susceptibility breakpoints of AMPC for H. pylori were: sensitive (AMPC-S); MIC < 0.04 microg/ml, intermittent resistance (AMPC-I); 0.04-1, resistant (AMPC-R); > 1.

RESULTS

No AMPC-R strains were detected in the strains isolated between 1985 and 1996, while the rate of resistance was determined to be 1.1%, 2.1%, 5.4%, 5.6%, 0%, 8.8%, and 1.5% every year, respectively, from 1997 to 2003. The percentage of AMPC-I strains increased from 2000 to 2003. The total eradication rate of H. pylori in the patients who received triple therapy containing AMPC was 81.4% (214/263). Classified as above, the rates of AMPC-S, AMPC-I, and AMPC-R were 84.6%, 77.8%, 25%, respectively.

CONCLUSION

H. pylori resistance to AMPC is still rare in Japan, although the percentage of AMPC-I strains has increased over the last 4 years. The frequency of isolation of strains showing true resistance to AMPC may increase in the future, along with an increase in the frequency of isolation of AMPC-I strains.

Inhibitory action of a new proton pump inhibitor, trifluoromethyl ketone derivative, against the motility of clarithromycin-susceptible and-resistant Helicobacter pylori

We previously reported that a trifluoromethyl ketone derivative, 1-(2-benzoxazolyl)-3,3,3-trifluoro-2-propanone (TF18), exhibited the potent antibacterial activity against Helicobacter pylori, but had no urease activity. In order to clarify the mechanism of anti-H. pylori action of TF18, we evaluated the growth and motility of TF18 on clarithromycin-susceptible H. pylori (CSHP) and -resistant H. pylori (CRHP). An effective proton pump inhibitor (TF18) had remarkable dose-dependent antibacterial activity and was able to inhibit the flagellar motor of both CSHP and CRHP isolates. The antimotility effect of TF18 was more pronounced at subinhibitory concentration in CRHP than in CSHP. The swimming (the forward motion) was more sensitive to the inhibition than the tumbling. Based on the results, it is supposed that TF18 works as an uncoupler similar to the 'clutch' in a biological motor, in which counterclockwise rotation is more sensitive to the effect of TF18 than the clockwise rotation.

The action of bismuth against Helicobacter pylori mimics but is not caused by intracellular iron deprivation

Helicobacter pylori is highly susceptible to bismuth, a heavy metal with antimicrobial activity linked to its effect on bacterial iron uptake. Three strains of H. pylori were analyzed for indicators of iron limitation following exposure to the MIC of colloidal bismuth subcitrate (MIC(CBS)). Similar morphologic and outer membrane changes were observed following growth in iron-limiting medium and at the MIC(CBS) that inhibited the growth of all three strains. These changes, which were also observed for iron-limited bacteria, were alleviated by the addition of iron to the cultures. H. pylori ATP levels, reduced in iron-limiting medium, were below the limits of detection in two of the three strains following exposure to bismuth. The addition of iron partially restored bacterial ATP levels in these two strains, although not to normal concentrations. In contrast, exposure of the same strains to the MIC(CBS) failed to deplete intracellular levels of iron, which were significantly reduced by culturing in iron-limiting medium. Thus, the antimicrobial effect of bismuth and of iron limitation on H. pylori may be similar. However, the respective mechanisms of intracellular action would appear to be mediated by different pathways within the cell.