Increased primary resistance to recommended antibiotics negatively affects Helicobacter pylori eradication

Molecular Docking of Anti Helicobacter pylori Antibiotics and Proton Pump Inhibitor: A Single Center Survey

Helicobacter pylorus (H. pylori) is a deadly bacterium responsible for significant worldwide Gastric Cancer (GC) related mortality. The present study aimed to screen all the anti-microbial drugs used to eradicate H .pylori infection and to identify the most efficient drug by using computational methods through molecular docking analysis. The 3-D structure of protein chorismate synthase of H. pylori was downloaded from the Protein data bank (PDB) online browser. The x-ray crystallography structures of 13 common drugs used against H.pylori infection were also downloaded from the drug bank. We screened all 13 common drugs through molecular docking to know the most efficient binding interaction between the diverse ligand-protein complexes. The results were further compared with clinical survey data from the patients with diverse gastrointestinal H. pylori infected cases. Among the screened compounds, by in-silico approach we found that fluoroquinolone (FLRQ) and tetracycline (TET) manifested more significant interactions with chorismate synthase (CS) protein along with binding energies of -9.2 and -8.1 kcal/mole respectively. Further, the drugs were also corroborated with the survey data from patients with varied gastrointestinal disorders in our study. With this computational study, we could find FLRQ and TET may be the most efficient drug for H. pylori treatment, which can be tried in case of anti H. Pylori treatment failure due to resistance. Hence, effective inter-analysis between the experimental and computational approaches is crucial to build up a strong inhibitor.

Helicobacter pylori infection and antibiotic resistance - from biology to clinical implications

Helicobacter pylori is a major human pathogen for which increasing antibiotic resistance constitutes a serious threat to human health. Molecular mechanisms underlying this resistance have been intensively studied and are discussed in this Review. Three profiles of resistance - single drug resistance, multidrug resistance and heteroresistance - seem to occur, probably with overlapping fundamental mechanisms and clinical implications. The mechanisms that have been most studied are related to mutational changes encoded chromosomally and disrupt the cellular activity of antibiotics through target-mediated mechanisms. Other biological attributes driving drug resistance in H. pylori have been less explored and this could imply more complex physiological changes (such as impaired regulation of drug uptake and/or efflux, or biofilm and coccoid formation) that remain largely elusive. Resistance-related attributes deployed by the pathogen cause treatment failures, diagnostic difficulties and ambiguity in clinical interpretation of therapeutic outcomes. Subsequent to the increasing antibiotic resistance, a substantial drop in H. pylori treatment efficacy has been noted globally. In the absence of an efficient vaccine, enhanced efforts are needed for setting new treatment strategies and for a better understanding of the emergence and spread of drug-resistant bacteria, as well as for improving diagnostic tools that can help optimize current antimicrobial regimens.

Comparing the Efficacy of Sequential and Standard Quadruple Therapy for Eradication of H. Pylori Infection

BACKGROUND

The aim of this study was comparison the effectiveness of sequential and standard quadruple therapy on eradication of H. pylori infection.

METHODS

This clinical trial study was conducted on 160 patients with dyspepsia or gastroduodenal ulcer. Patients were randomly divided into two groups. Group A (standard regimen) received omeprazole, amoxicillin, clarithromycin and bismuth subcitrate for 2 weeks. Group B (sequential regimen) received omeprazole and amoxicillin in 5 days and omeprazole, tinidazole and levofloxacin in 5 days. After the end of treatment regimens, 20 mg omeprazole was administered twice daily for 3 weeks. H. pylori eradication was assessed 2 months after antibiotic treatment via fecal antigen.

RESULTS

Frequency of H. pylori eradication in group A and B was observed in 55 (68.8%) and 63 patients (78.8%), respectively. No significant difference was seen between two groups, regarding H. pylori eradication (p = 0.15). The most common side effects in group A, B were bitterness of mouth (63.8%) and nausea (16.2%), respectively (p H. pylori infection, higher rate of H. pylori eradication was seen in group B than group A. Thus, sequential regimen was a more appropriate regimen with fewer complications.

Anti-Helicobacter pylori Activity of Isocoumarin Paepalantine: Morphological and Molecular Docking Analysis

The Helicobacterpylori bacterium is one of the main causes of chronic gastritis, peptic ulcers, and even gastric cancer. It affects an average of half of the world population. Its difficult eradication depends upon multi-drug therapy. Since its classification as a group 1 carcinogenic by International Agency for Research on Cancer (IARC), the importance of H. pylori eradication has obtained a novel meaning. There is considerable interest in alternative therapies for the eradication of H. pylori using compounds from a wide range of natural products. In the present study, we investigated the antibacterial property of the isocoumarin paepalantine against H. pylori and it exhibited significant anti-H. pylori activity at a minimum inhibitory concentration (MIC) of 128 μg/mL and at a minimum bactericidal concentration (MBC) of 256 μg/mL. The scanning electron microscopy (SEM) revealed significant morphological changes of the bacterial cell as a response to a sub-MIC of paepalantine, suggesting a penicillin-binding protein (PBP) inhibition. Computational studies were carried out in order to study binding modes for paepalantine in PBP binding sites, exploring the active and allosteric sites. The data from the present study indicates that paepalantine exhibits significant anti-H. pylori activity, most likely by inhibiting membrane protein synthesis.

A comparison between standard triple therapy and sequential therapy on eradication of Helicobacter pylori in uremic patients: A randomized clinical trial

Background:

The prevalence of peptic ulcer disease in hemodialysis dependent patients is higher than the general population. These patients are also more prone to upper gastrointestinal bleeding. The aim of this study was to compare the effects of a standard triple therapy with a sequential therapy on Helicobacter pylori eradication in azotemic and hemodialysis patients.

Materials and Methods:

Forty nine hemodialysis and azotemic patients, naïve to H. pylori treatment, were randomized into two groups to receive either standard triple therapy (pantoprazole 40 mg, amoxicillin 500 mg and clarithromycin 250 mg twice a day for 14 days) or a sequential therapy (pantoprazole 40 mg for 10 days, amoxicillin 500 mg twice a day for the first 5 days and clarithromycin 250 mg + tinidazole 500 mg twice a day just during the second 5 days). H. pylori eradication was evaluated by fecal H. pylori antigen assessment 8 weeks after the treatment.

Results:

Of 49 patients, 45 patients (21 in triple therapy group and 24 in the sequential group) completed the study. Based on intention to treat analysis, H. pylori eradication rates were 66.7% (95% confidence interval [CI]: 47.8-85.5%) in standard triple therapy group and 84% (95% CI: 69.6-98.3%) in sequential therapy group (P = 0.34). Per-protocol (PP) eradication rates were (95% CI: 76.2%. 6-89.3%) 54 and 87.5% (95% CI: 68.8-95.5%), respectively (P = 0.32).

Conclusion:

According to Maastricht III consensus report, the results of our study showed that sequential therapy might be a better choice compared with the standard triple therapy in azotemic and hemodialysis patients Iran. We propose to assess the effects of shorter-duration sequential therapy (less than 10 days) for H. pylori eradication.

Pretreatment antimicrobial susceptibility-guided vs. clarithromycin-based triple therapy for Helicobacter pylori eradication in a region with high rates of multiple drug resistance

OBJECTIVES

Helicobacter pylori eradication rates with clarithromycin-based triple therapy are declining, and an alternative strategy is needed urgently. We sought to compare the efficacy of pretreatment antimicrobial susceptibility-guided vs. clarithromycin-based triple therapy for H. pylori eradication in a region with high rates of multiple drug resistance.

METHODS

Consecutive H. pylori-infected patients with gastric epithelial neoplasms were randomized to receive antimicrobial susceptibility-guided therapy or clarithromycin-based triple therapy for 7 days. In patients in whom the infection was not eradicated, antibiotics were given according to an initial antimicrobial susceptibility test as a second-line therapy in both groups. Eradication rates, antibiotics resistance rates, and drug compliance owing to adverse effects were compared between the groups.

RESULTS

In total, 114 patients were enrolled, and 112 completed the protocols. Drug compliance and side effects were similar between the groups. The intention-to-treat eradication rates were 94.7% (95% confidence interval (CI)=88.8-100%, 54/57) in the antimicrobial susceptibility-guided group and 71.9% (95% CI=60.2-83.5%, 41/57) in the clarithromycin-based triple therapy group after the initial treatment (P=0.002), whereas the per-protocol (PP) eradication rates were 96.4% (95% CI=91.5-100%, 54/56) in the antimicrobial susceptibility-guided group and 73.2% (95% CI=61.5-84.8%, 41/56) in the clarithromycin-based triple therapy group (P=0.001). In H. pylori with clarithromycin resistance, the eradication failure rate with first-line treatment was lower in the susceptibility-guided therapy group (0%, 0/12) compared with the clarithromycin-based triple therapy group (80.0%, 95% CI=59.7-100%, 12/15) by PP analysis (P<0.001).

CONCLUSIONS

Pretreatment antimicrobial susceptibility-guided therapy is more effective than clarithromycin-based triple therapy for H. pylori eradication in a region with high rates of multiple drug resistance.

Sequential Therapy vs Quadruple Therapy for Helicobacter pylori Eradication in South West of Iran

Aim

To compare the efficacy of quadruple and sequential therapy in eradication of Helicobocter pylori (H. pylori) in a randomized study.

Method

Three hundred H. pylori positive patients were enrolled into the study. These patients were randomly divided into two groups: group I (n = 150) received quadruple therapy (20 mg omeprazole bid, 240 mg bismuth subcitrate bid, 1,000 mg tetracycline bid and 500 mg metronidazole bid) for 14 days, group II (n = 150) received sequential therapy (20 mg omeprazole bid, 1,000 mg amoxicillin bid for 5 days, followed by 20 mg omeprazole bid, 500 mg metronidazole bid, 500 mg clarithromycin for the other 5 days). H. pylori status was assessed by histology and rapid urease test at baseline. Follow-up breath test by 14C urea breath test (UBT) was performed 4 weeks after completion of treatment. Eradication was defined as negative results on UBT.

Results

Successful eradication was achieved in 245 patients. In each group, five patients did not tolerate the regimen and were excluded from analysis. About 29 (20%) patients who received sequential therapy and 21 (14.5%) of the quadruple group tolerated mild side effects (p = 0.21).

Per-protocol analysis demonstrated eradication rates of 86.9% for sequential therapy and 82.7% for quadruple therapy (p = 0.26). Results according to the intention to treat analysis were 84 and 79.5% in the sequential and quadruple group respectively. Eradication rate differences were not significant.

Conclusion

The success rate of sequential therapy is comparable with quadruple therapy. Sequential therapy due to the short duration and lesser drug usage is a good alternative for eradication of H. pylori in the country.

How to cite this article: Masjedizadeh AR, Hajiani E, Hashemi SJ, Alavinejad P, Dalvand H. Sequential Therapy vi Quadruple Therapy for Helicobocter pylori Eradication in South West of Iran. Euroasian J Hepato-Gastroenterol 2014;4(2):63-66.

Sequential therapy versus standard triple-drug therapy for Helicobacter pylori eradication: result of the HPFEZ randomised study

OBJECTIVE

The aim of this study was to assess and compare the efficacy and safety of sequential treatment with standard triple therapies in a located population in Morocco.

METHODS

Consecutive H. pylori-positive patients with endoscopy-proven ulcer or non ulcer dyspepsia were prospectively randomized in the trial into one of three groups: AM and AC group were administered a tri-therapy for 7 days including PPI + amoxicillin + metronidazole (AM group)/clarithromycin (AC group) and SQ group was administered a sequential regimen consisting of PPI + amoxicillin for 5 days followed by PPI + clarithromycin + metronidazole for the remaining 5 days. Eradication was confirmed by 13C-urea breath test 3 months after the end of the treatment.

RESULTS

Groups AM, AC and SQ included respectively 104, 115 and 104 patients. They were comparable in terms of age, sex, clinical and endoscopic presentation. The rate of H. pylori eradication with sequential therapy was found at 94.2% (n=98) in ITT and 96% (n=98) in PP. It was higher than those found in the AM group: 70% (n=73) in ITT and 70.8% (n=73) in PP and the AC group: 78.2% (n=90) in ITT and 79.6% (n=90) in PP (0.001). The prevalence of side effects following the sequential treatment was 9.6% (n=10) versus 22% (n=22) and 27.8% (n=32) in the AM and AC groups, respectively, (P=0.006).

CONCLUSIONS

Sequential treatment was better tolerated and achieved a significantly higher eradication rate of H. pylori compared with standard triple therapies in this population.

Helicobacter pylori antibiotic resistance in Brazil: clarithromycin is still a good option

CONTEXT

The antibiotic susceptibility is the cornerstone for the eradication therapies of Helicobacter pylori.

OBJECTIVES

To evaluate the prevalence of primary resistance of H. pylori was evaluated in an urban Brazilian population.

METHODS

H. pylori isolates were obtained from patients submitted to an upper gastrointestinal endoscopy for the evaluation of dyspeptic symptoms. Biopsies from antrum, corpus and fundus were taken to determine the antibiotic susceptibility of H. pylori isolates. The minimal inhibitory concentration of furazolidone and bismuth were routinely determined by agar dilution method and the minimal inhibitory for amoxicillin, clarithromycin, tetracycline, levofloxacin, and metronidazole were routinely determined with the E-test.

RESULTS

Fifty-four patients were included. In vitro antimicrobial susceptibility of H. pylori strains were obtained from 39 patients. Resistance to metronidazole was detected in 20 patients (51%), to clarithromycin in 3 patients (8%), to levofloxacin in 9 patients (23%) and to bismuth in 2 patients (5%). There was no observed resistance to amoxicillin, tetracycline or furazolidone.

CONCLUSION

Due to the low amoxicillin and clarithromycin resistance observed in this study, therapies using these antimicrobials remain appropriated first-line H. pylori therapy.

Modified Sequential Therapy Regimen versus Conventional Triple Therapy for Helicobacter Pylori Eradication in Duodenal Ulcer Patients in China: A Multicenter Clinical Comparative Study. Gastroenterol Res Pract. 2012;2012:405425. [PMID: 22550478 PMCID: PMC3329148 DOI: 10.1155/2012/405425]

Objective. Antimicrobial resistance has decreased eradication rates for Helicobacter pylori infection worldwide. To observe the effect of eradicating Helicobacter pylori (H. pylori) and the treatment of duodenal ulcer by 2 kinds of modified sequential therapy through comparing with that of 10-day standard triple therapy. Methods. A total of 210 patients who were confirmed in duodenal ulcer active or heal period by gastroscopy and H. pylori positive confirmed by rapid urease test, serum anti-H. pylori antibody (ELASE), or histological examination enrolled in the study. All the patients were randomly divided into three groups: group A (70 cases) and group B (70 cases) were provided 10-day modified sequential therapy; group C (70 cases) was provided 10-day standard triple therapy. Patients of group A received 20 mg of Esomeprazole, 500 mg of Clarithromycin for the first 5 days, followed by 20 mg of Esomeprazole, 500 mg of Clarithromycin, and 1000 mg of Amoxicillin for the remaining 5 days. Group B received 20 mg of Esomeprazole, 1000 mg of Amoxicillin for the first 5 days, followed by 20 mg of Esomeprazole, 500 mg of Clarithromycin, and 1000 mg of Amoxicillin for the remaining 5 days. Group C received 20 mg of Esomeprazole, 500 mg of Clarithromycin, and 1000 mg of Amoxicillin for standard 10-day therapy. All drugs were given twice daily. H. pylori eradication rate was checked four to eight weeks after taking the medicine by using a ¹³C urea breath test. In the first, second, third, seventh, twenty-first, thirty-fifth days respectively, the symptoms of patients such as epigastric gnawing, burning pain, and acidity were evaluated simultaneously. Results. Overall, 210 patients accomplished all therapy schemes, 9 case patients were excluded. The examination result indicated that the H. pylori eradication rate of each group was as follows: group A 92.5% (62/67), group B 86.8% (59/68), and group C 78.8% (52/66). The H. pylori eradication rate of group A was slightly higher than group B (P < 0.05) and both of them were obviously higher than group C (P < 0.05). Modified sequential therapy was significantly more effective in patients with clarithromycin-resistant strains (80%/67% versus 31%; P = 0.02). Symptoms improvement: all the three groups could improve the symptoms such as epigastric gnawing, burning pain, and acidity since the first day. There was no significant difference in total score descending of symptoms between each group (P > 0.05). Conclusions. All the three therapy schemes could alleviate symptoms of duodenal ulcer patients in China efficiently. But as far as eradicating H. pylori is concerned, the modified sequential therapy was better than standard triple therapy, especially the therapy scheme used in group A.

Change in antibiotic resistance of Helicobacter pylori strains and the effect of A2143G point mutation of 23S rRNA on the eradication of H. pylori in a single center of Korea

BACKGROUND

The current prevalence of primary antibiotic resistance of H. pylori is not known in Korea. This study was done to evaluate the prevalence of primary antibiotic resistance of H. pylori, and to evaluate the effect of point mutations of 23S rRNA on the rate of eradication of H. pylori.

METHODS

H. pylori were isolated from gastric mucosal biopsy specimens obtained from 222 Koreans. The susceptibilities of the H. pylori isolates to amoxicillin, clarithromycin, metronidazole, tetracycline, ciprofloxacin, and levofloxacin were examined using the agar dilution method. DNA sequencing was carried out to detect H. pylori 23S rRNA mutations.

RESULTS

The resistance to clarithromycin, tetracycline, ciprofloxacin, and levofloxacin increased during the period of 2007 to 2009 compared with 2003 to 2005 (P<0.05). However, amoxicillin and metronidazole resistance slightly decreased. The rates of eradication were 95.5% for the clarithromycin-sensitive strains, which was higher than the 67.9% for the clarithromycin-resistant strains (P=0.001). By contrast, the eradication rate was 100% in patients with amoxicillin-resistant H. pylori. Among 26 clarithromyin-resistant strains, 6 (23%) had A2143G mutations, and all of the cases in which these mutations were present were not eradicated by proton pump inhibitor-based triple therapy (P=0.0004). By contrast, none of the 26 clarithromyin-sensitive strains had A2143G mutations. The T2183C and A2223G mutations were frequently found in the sensitive strains and in the resistant strains.

CONCLUSIONS

Clarithromycin resistance of H. pylori, which determined the efficacy of H. pylori eradication of proton pump inhibitor triple regimen, was found to be increased in a single center study. A2143G was an important 23S rRNA mutation associated with clarithromycin resistance and affected the H. pylori eradication efficacy.

Anti-secretory, anti-inflammatory and anti-Helicobacter pylori activities of several fractions isolated from Piper carpunya Ruiz & Pav

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Piper carpunya Ruiz & Pav. (syn Piper lenticellosum C.D.C.) (Piperaceae), are widely used in folk medicine in tropical and subtropical countries of South America as an anti-inflammatory, anti-ulcer, anti-diarrheal and anti-parasitical remedy as well as an ailment for skin irritations.

AIMS OF THE STUDY

To study the anti-inflammatory, anti-secretory and anti-Helicobacter pylori activities of different fractions isolated from an ethanolic extract of the leaves of Piper carpunya, in order to provide evidence for the use of this plant as an anti-ulcer remedy. Moreover, to isolate the main compounds of the extract and relate their biological activity to the experimental results obtained with the fractions.

MATERIALS AND METHODS

Sixteen fractions were obtained from the ethanolic extract (F I-XVI) and 16 pure compounds were isolated and identified from these fractions. We studied the effects of the fractions (0.1-400microg/mL) on the release of myeloperoxidase (MPO) enzyme from rat peritoneal leukocytes, on rabbit gastric microsomal H(+), K(+)-ATPase activity and anti-Helicobacter pylori anti-microbial activity using the microdilution method (MM). The main compounds contained in the fractions were isolated and identified by (1)H- and (13)C NMR spectra analysis and comparison with the literature data.

RESULTS

Eight fractions showed inhibition of MPO enzyme (F I-IV, X, XII, XIV and XV). The highest inhibition was observed with F XIV (50microg/mL, 60.9%, p<0.001). F X and XII were the most active ones, inhibiting the gastric H(+), K(+)-ATPase activity with IC(50) values equal to 22.3microg/mL and 28.1microg/mL, respectively. All fractions, except F XV, presented detectable anti-Helicobacter pylori activity, with a diameter of inhibition zones ranging from 11mm up to 50mm. The best anti-Helicobacter pylori activity was obtained with F III and V. Both fractions killed Helicobacter pylori with lowest concentration values, about 6.25mug/mL. Sixteen pure compounds were isolated, five of them are flavonoids that possess strong anti-oxidant and free radical scavenging activity, e.g. vitexin, isovitexin, and rhamnopyranosylvitexin. Terpenoids like sitosterol, stigmasterol and phytol, which have shown gastroprotective activity, and dihydrochalcones, like asebogenin, with anti-bacterial activity, were also isolated. Furthermore, the rare neolignan 1, that is a DNA polymerase beta lyase inhibitor, and (6S, 9S)-roseoside, that shows strong anti-bacterial activity, were isolated, for the first time, from the genus Piper.

CONCLUSIONS

We suggest that the flavonoids isolated from F I and II (vitexin, isovitexin, rhamnopyranosylvitexin and isoembigenin) contribute to the anti-MPO activity, as well as to their anti-Helicobacter pylori activity. These flavonoids may also be responsible for the important inhibition of H(+), K(+)-ATPase activity. Also the phytosterols and phytol obtained from F XIV and XV could be involved in these gastroprotective activities. These results encourage us to continue phytochemical studies on these fractions in order to obtain full scientific validation for this species.

Is antimicrobial susceptibility testing necessary before first-line treatment for Helicobacter pylori infection? Meta-analysis of randomized controlled trials

BACKGROUND

With the wide use of antibiotics, antibiotic-resistant Helicobacter pylori strains are becoming increasingly prevalent. It has been hypothesized that culture-guided therapy might help to increase treatment success. But the effects and the costs still remain controversial.

AIMS

To systematically review the efficacy and the cost of culture-guided triple therapy, compared to standard triple regimen for first-line treatment of Helicobacter pylori infection.

METHODS

A search of the Cochrane Library, PubMed, EMBASE, Science Citation Index Expanded and CBM was performed. Randomized controlled trials comparing culture-guided triple therapy to standard triple therapy in the first-line treatment of Helicobacter pylori infection were selected for meta-analysis. Relative risk was used as a measure of the effect of two regimens mentioned above with a fixed-effects model using the methods of DerSimonian and Laird.

RESULTS

Five randomized controlled trials totaling 701 patients were included. The meta-analysis showed that culture-guided triple therapy was superior referring to a higher eradication rate from intention-to-treat analyses (RR, 0.84; 95% CI,0.77, 0.90; p<0.00001) and a lower overall cost.

CONCLUSION

Culture-guided triple therapy was more effective than standard triple therapy for first-line treatment of Helicobacter pylori infection. Based on the only paper focused on the overall cost, the culture-guided triple therapy was also more cost saving. Antimicrobial susceptibility testing is necessary before first-line treatment for Helicobacter pylori infection.

Amoxicillin resistance with beta-lactamase production in Helicobacter pylori

BACKGROUND

Amoxicillin-resistant Helicobacter pylori with minimal inhibitory concentration (MIC) >or= 256 mg L(-1) was isolated from a gastritis patient. The aims were to investigate the mechanism of high-level amoxicillin resistance in H. pylori.

MATERIALS AND METHODS

The beta-lactamase production was determined by means of nitrocefin sticks and the presence of gene encoding the beta-lactam antibiotic resistance enzyme TEM beta-lactamase was analysed by polymerase chain reaction (PCR), sequencing and dot-blot hybridization. Sequencing analysis of pbp1A gene was performed and amoxicillin-susceptible isolate was transformed with pbp1A PCR products from the resistant isolate. The expression of hefC efflux system was analysed using real-time quantitative PCR.

RESULTS

Activity of beta-lactamase was detected. Sequence analysis showed that the PCR product derived from H. pylori 3778 was identical to the bla(TEM-1) (GenBank accession EU726527). Dot-blot hybridization confirmed the presence of beta-lactamase gene bla(TEM-1.) By transformation of PCR product of mutated pbp1A gene from H. pylori 3778 into amoxicillin-susceptible strain showed that substitutions in Thr(556)-->Ser, Lys(648)-->Gln, Arg(649)-->Lys and Arg(656)-->Pro contribute to low-level amoxicillin resistance. The MIC of amoxicillin for the transformants was 0.75 mg L(-1). Over-expression of hefC was not found.

CONCLUSIONS

High-level amoxicillin resistance is associated with beta-lactamase production in H. pylori. Low-level amoxicillin resistance is linked to a point mutation on pbp1A. Because H. pylori can exchange DNA through natural transformation, spreading of bla(TEM-1) amoxicillin resistance gene among H. pylori is a potential threat when treating H. pylori infection.

Short-term triple therapy with azithromycin for Helicobacter pylori eradication: low cost, high compliance, but low efficacy

BACKGROUND

The Brazilian consensus recommends a short-term treatment course with clarithromycin, amoxicillin and proton-pump inhibitor for the eradication of Helicobacter pylori (H. pylori). This treatment course has good efficacy, but cannot be afforded by a large part of the population. Azithromycin, amoxicillin and omeprazole are subsidized, for several aims, by the Brazilian federal government. Therefore, a short-term treatment course that uses these drugs is a low-cost one, but its efficacy regarding the bacterium eradication is yet to be demonstrated. The study's purpose was to verify the efficacy of H. pylori eradication in infected patients who presented peptic ulcer disease, using the association of azithromycin, amoxicillin and omeprazole.

METHODS

Sixty patients with peptic ulcer diagnosed by upper digestive endoscopy and H. pylori infection documented by rapid urease test, histological analysis and urea breath test were treated for six days with a combination of azithromycin 500 mg and omeprazole 20 mg, in a single daily dose, associated with amoxicillin 500 mg 3 times a day. The eradication control was carried out 12 weeks after the treatment by means of the same diagnostic tests. The eradication rates were calculated with 95% confidence interval.

RESULTS

The eradication rate was 38% per intention to treat and 41% per protocol. Few adverse effects were observed and treatment compliance was high.

CONCLUSION

Despite its low cost and high compliance, the low eradication rate does not allow the recommendation of the triple therapy with azithromycin as an adequate treatment for H. pylori infection.

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

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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.

In vitro antimicrobial susceptibility testing of Helicobacter felis, H. bizzozeronii, and H. salomonis

The susceptibilities of Helicobacter felis (15 strains), H. bizzozeronii (7 strains), and H. salomonis (3 strains) to 10 antimicrobial agents were investigated by determination of the MIC using the agar dilution method. No consistent differences were noticed between the different Helicobacter species, which were all highly susceptible to ampicillin, clarithromycin, tetracycline, tylosin, enrofloxacin, gentamicin, and neomycin, as demonstrated by low MICs. Higher MICs were obtained for lincomycin (up to 8 microg/ml) and spectinomycin (up to 4 microg/ml). Two H. felis strains showed a MIC of 16 microg/ml for metronidazole, suggesting acquired resistance to this antimicrobial agent.

One-week dual therapy with ranitidine bismuth citrate and clarithromycin for the treatment of Helicobacter pylori infection in Brazilian patients with peptic ulcer

AIM: To assess the efficacy and safety of ranitidine bismuth citrate plus clarithromycin given for 1 wk in Brazilian patients with peptic ulcer.

METHODS: One hundred and twenty patients with peptic ulcer were randomized in two treatment groups: (1) 1-wk regimen consisting of ranitidine bismuth citrate 400 mg b.i.d. with clarithromycin 500 mg b.i.d. or (2) 2-wk regimen of the same treatment. Eradication of the infection was considered when both the histologic examination and the urease test were negative for the infection 3 mo after treatment.

RESULTS: By intention to treat analysis, Helicobacter pylori (H pylori) was eradicated in 73% and 76% of patients, respectively treated for 1 or 2 wk (P>0.05). By per protocol analysis, the eradication rates were 80% and 83%, respectively, in patients treated for 1 or 2 wk (P>0.05). Nine patients (8.2%) reported minor side effects.

CONCLUSION: One-week therapy with ranitidine bismuth citrate and clarithromycin is safe, well tolerated and effective for treatment of H pylori infection, and appears to be comparable to the 2-wk regimen in terms of efficacy.

New once-daily, highly effective rescue triple therapy after multiple Helicobacter pylori treatment failures: a pilot study

BACKGROUND

Helicobacter pylori treatment failure is a growing problem in daily practice.

AIM

To determine the efficacy of the combination of rabeprazole, levofloxacin and furazolidone as a rescue therapy.

METHODS

Duodenal ulcer patients previously submitted, without success, to at least two H. pylori treatment regimens were included. Gastroscopy (urease test, histological examination and culture) and (13)C-urea breath test were performed. All patients received a combination of rabeprazole 20 mg, levofloxacin 500 mg and furazolidone 200 mg (two tablets) administered in a single dose in the morning for 10 days. Clinical examination and a new (13)C-urea breath test were performed 90 days after therapy.

RESULTS

Twelve patients (eight females and four males), mean age 43 (30-58) years were included. Two patients failed to complete the treatment because of nausea and vomiting. Ten patients completed the study and took all the medications as advised. Culture was obtained in six patients: 100 and 83% of the samples were sensitive to furazolidone and levofloxacin, respectively. Per-protocol and intention-to-treat eradication rates were 100 and 83% (P = 0.019).

CONCLUSIONS

the combination of rabeprazole, levofloxacin and furazolidone in a single daily dose for 10 days constitutes a highly-effective and low-cost alternative as a third-line therapy in patients infected with H. pylori.

Role of antibiotic sensitivity testing before first-line Helicobacter pylori eradication treatments

BACKGROUND

The resistance of Helicobacter pylori to antibiotics has been advocated as a major cause of treatment failure, and antimicrobial sensitivity testing has been proposed to improve efficacy; however, its role before first-line therapy has not been investigated in detail.

AIM

To assess whether antimicrobial sensitivity testing improves the eradication rate of first-line anti-Helicobacter treatments and to compare the effectiveness of ranitidine bismuth citrate and omeprazole in the presence of H. pylori resistance to antibiotics.

METHODS

Two hundred and forty-two patients were assigned to either empirical or antimicrobial sensitivity testing-based treatment; within each group, subjects were further randomized to receive ranitidine bismuth citrate, 400 mg b.d., tinidazole, 500 mg b.d., and clarithromycin, 500 mg b.d., or omeprazole, 20 mg b.d., clarithromycin, 500 mg b.d., and amoxicillin, 1 g b.d., for 1 week, with substitution of the resistant antibiotic in the antimicrobial sensitivity testing-based treatment group.

RESULTS

Eradication rates were 67% [confidence interval (CI), 55-79%] in the empirical treatment group and 76% (CI, 65-87%) in the antimicrobial sensitivity testing-based group (P=N.S.). The overall success rate was 60% (CI, 51-69%) with omeprazole and 82% (CI, 73-91%) with ranitidine bismuth citrate (P<0.03); the latter overcame antibiotic resistance in 12 of 15 strains vs. zero of eight strains by omeprazole.

CONCLUSIONS

Antimicrobial sensitivity testing before first-line treatment does not improve the eradication rate, which is greater when ranitidine bismuth citrate is included in the treatment.

Randomized study of different 'second-line' therapies for Helicobacter pylori infection after failure of the standard 'Maastricht triple therapy'

BACKGROUND

Triple therapy with proton pump inhibitor, clarithromycin and amoxicillin and, in the event of eradication failure, quadruple therapy with proton pump inhibitor, bismuth, tetracycline and metronidazole have been proposed in Maastricht as the optimal sequential treatment of Helicobacter pylori infection.

AIM

To compare two second-line regimens with quadruple therapy.

METHODS

One hundred and eighty patients with a previous failed course of standard therapy were randomly given one of the following 7-day treatments: ranitidine bismuth citrate 400 mg b.d. plus amoxicillin 1 g b.d. and tinidazole 500 mg b.d. (RBCAT), pantoprazole 40 mg b.d. plus amoxicillin 1 g b.d. and levofloxacin 500 mg/day (PAL) and pantoprazole 40 mg b.d., bismuth citrate 240 mg b.d., tetracycline 500 mg q.d.s. and metronidazole 500 mg b.d. (PBTM). The eradication rate was assessed by 13C-urea breath test. Side-effects and compliance were evaluated by a standardized questionnaire and by counting returned medication.

RESULTS

The RBCAT, PAL and PBTM groups achieved mean intention-to-treat eradication rates of 85%, 63% and 83%, respectively (P<0.05 for PAL vs. either RBCAT or PBTM). Compliance was optimal in all patients, although side-effects were more commonly observed in the PBTM group than in the other two patient groups (P<0.0001).

CONCLUSIONS

Both RBCAT and PBTM can be used as second-line therapies. Conversely, PAL did not achieve satisfactory eradication rates.

Analysis of antimicrobial susceptibility and virulence factors in Helicobacter pylori clinical isolates

BACKGROUND

In this study, we evaluated the prevalence of primary resistance of Brazilian H. pylori isolates to metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone. In addition, the vacA, iceA, cagA and cagE genotypes of strains isolated from Brazilian patients were determined and associated with clinical data in an effort to correlate these four virulence markers and antibiotic resistance.

METHODS

H. pylori was cultured in 155 H. pylori-positive patients and MICs for metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone were determined by the agar dilution method. Genomic DNA was extracted, and allelic variants of vacA, iceA, cagA and cagE were identified by the polymerase chain reaction.

RESULTS

There was a strong association between the vacA s1/cagA -positive genotype and peptic ulcer disease (OR = 5.42, 95% CI 2.6-11.3, p = 0.0006). Additionally, infection by more virulent strains may protect against GERD, since logistic regression showed a negative association between the more virulent strain, vacA s1/cagA-positive genotype and GERD (OR = 0.26, 95% CI 0.08-0.8, p = 0.03). Resistance to metronidazole was detected in 75 patients (55%), to amoxicillin in 54 individuals (38%), to clarithromycin in 23 patients (16%), to tetracycline in 13 patients (9%), and to furazolidone in 19 individuals (13%). No significant correlation between pathogenicity and resistance or susceptibility was detected when MIC values for each antibiotic were compared with different vacA, iceA, cagA and cagE genotypes.

CONCLUSION

The analysis of virulence genes revealed a specific association between H. pylori strains and clinical outcome, furthermore, no significant association was detected among pathogenicity and resistance or susceptibility.

High eradication rates of Helicobacter pylori with a new sequential treatment

BACKGROUND

Eradication rates of Helicobacter pylori with standard triple therapy are disappointing, and studies from several countries confirm this poor performance.

AIM

To assess the eradication rate of a new sequential treatment regimen compared with conventional triple therapy for the eradication of H. pylori infection.

METHODS

One thousand and forty-nine dyspeptic patients were studied prospectively. H. pylori-infected patients were randomized to receive 10-day sequential therapy [rabeprazole (40 mg daily) plus amoxicillin (1 g twice daily) for the first 5 days, followed by rabeprazole (20 mg), clarithromycin (500 mg) and tinidazole (500 mg) twice daily for the remaining 5 days] or standard 7-day therapy [corrected] [rabeprazole (20 mg), clarithromycin (500 mg) and amoxicillin (1 g) twice daily]. H. pylori status was assessed by histology, rapid urease test and 13C-urea breath test at baseline and 6 weeks or more after completion of treatment.

RESULTS

Higher eradication rates were found with the sequential regimen compared to the standard regimen (intention-to-treat: 92% vs. 74%, P < 0.0001; per protocol: 95% vs. 77%, P < 0.0001). Higher eradication rates were also seen in patients with peptic ulcer disease and non-ulcer dyspepsia. In both treatments, compliance was similar (> 90%), as was the rate of side-effects, which were mild.

CONCLUSIONS

This 10-day sequential treatment regimen achieves high eradication rates in peptic ulcer disease and non-ulcer dyspepsia.

Amoxicillin and ampicillin are not transferred to gastric juice irrespective of Helicobacter pylori status or acid blockade by omeprazole

BACKGROUND

The effects of proton pump inhibitors and Helicobacter pylori infection on the distribution of drugs used for the eradication of the bacteria are poorly understood.

AIM

The aim of this study was to investigate the effects of a 7-day administration of 20 mg of omeprazole on the pharmacokinetics of amoxicillin and ampicillin in the plasma, saliva and gastric juice of individuals with and without H. pylori infection.

METHODS

Fifty-four healthy volunteers without endoscopic lesions were enrolled. Twenty-six volunteers were included in the amoxicillin study and 28 individuals in the ampicillin study. Each study had an open randomized two-period crossover design and a 21-day washout period between phases. Plasma, saliva and gastric juice concentrations of amoxicillin and ampicillin in subjects with and without omeprazole pre-treatment were measured by reversed-phase HPLC using UV detection.

RESULTS

Neither pre-treatment with omeprazole nor H. pylori infection interfered with the plasma bioavailability of amoxicillin or ampicillin, as assessed by the AUC0-2 h. Neither ampicillin nor amoxicillin were detected in saliva or gastric juice in any study phase.

CONCLUSION

Short-term treatment with omeprazole does not interfere with the pharmacokinetics of amoxicillin or ampicillin. Our results also exclude the presence of a transfer mechanism for amoxicillin or ampicillin from the plasma to the gastric lumen.