Prevalence of Helicobacter pylori resistance to metronidazole, clarithromycin, amoxicillin, tetracycline, and furazolidone in Brazil

A Comprehensive Study to Identify Major Metabolites of an Amoxicillin–Sulbactam Hybrid Molecule in Rats and Its Metabolic Pathway Using UPLC-Q-TOF-MS/MS

Amoxicillin and sulbactam are widely used compound drugs in animal food. The amoxicillin–sulbactam hybrid molecule can achieve better curative effects through the combination of the two drugs. However, its pharmacokinetic behavior needs to be explored. In this study, a randomized crossover experiment was performed to investigate the metabolism of the novel amoxicillin–sulbactam hybrid molecule in rats after gastric administration. Ultrahigh performance liquid chromatography–quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) was used to isolate and to identify the metabolites in rats. Amoxicillin, amoxicilloic acid, amoxicillin diketopiperazine, and sulbactam were eventually detected in the plasma, liver, urine, and kidneys; no hybrid molecules and their metabolites were detected in feces. The in vivo metabolism results showed that the hybrid molecule was absorbed into the body in the intestine, producing amoxicillin and sulbactam, then amoxicillin was partially metabolized to amoxicilloic acid and amoxicillin diketopiperazine, which are eventually excreted in the urine by the kidneys. In this study, four major metabolites of the amoxicillin–sulbactam hybrid molecule were identified and their metabolic pathways were speculated, which provided scientific data for understanding the metabolism of the hybrid molecule and for its clinical rational use.

Clarithromycin-Susceptible But Virulent Helicobacter pylori Strains Infecting Iranian Patients' Stomachs

Introduction

Helicobacter pylori was discovered first in the stomachs of patients with gastritis and ulcers by Marshall and Warren in 1982. This discovery majorly affected many research areas of gastroenterology. Since then, the main aim has been to eradicate this microaerophilic bacterium from the stomachs of infected subjects.

Methods

We studied symptomatic cases by endoscopic surgery and examined the prevalence of cagA-vacA genotypes among the H. pylori isolates. H. pylori isolated from antral biopsies of patients with gastritis and duodenal ulcer were subjected to antimicrobial susceptibility testing and PCR genotyping by using routine bacterial cultures. Clarithromycin-susceptibility profiling was done by the E-test. DNA was extracted using standard manufacturer protocols with minor modifications and cagA and vacA genotyping was done PCR.

Results

In our study, all strains identified as H. pylori in culture (61/81) were confirmed by PCR by amplifying a fragment of the glmM gene. Totally, 61 patients were confirmed to be positive for H. pylori and they were included in the genotyping and antibiotic-susceptibility testing. Thirteen H. pylori strains were determined to be resistant to clarithromycin.

Discussion

Current accumulating data indicate that both clarithromycin-resistant and susceptible isolates of H. pylori need to be screened and tracked in populations.

Broad spectrum resistance in Helicobacter pylori isolated from gastric biopsies of patients with dyspepsia in Cameroon and efflux-mediated multiresistance detection in MDR isolates

Background

Antibiotic resistance is a leading cause of treatment failure in Helicobacter pylori infection. In Africa, there are very little data concerning the susceptibility of Helicobacter pylori isolates to antibiotics. The purpose of this study was to evaluate the resistance prevalence of Helicobacter pylori strains circulating in Cameroon, and to assess overexpression of efflux pump as a possible multi-drug resistance mechanisms.

Methods

A total of 140 H. pylori isolates were recovered from gastric biopsies of dyspeptic patients in two reference hospitals in Cameroon and analyzed for their antimicrobial susceptibility to amoxicillin, co-amoxiclav, ampicillin, penicillin, imipenem, metronidazole, rifabutin, erythromycin, clarithromycin, azithromycin, levofloxacin, ciprofloxacin, norfloxacin, tetracycline, doxycycline and minocycline. Antibiotic sensitivity was tested by disk diffusion method. Phe-Arg-naphthylamide (PAßN) was used as efflux pump inhibitor. INT broth microdilution method in supplemented Brain Heart Infusion broth was used to determine the MIC of ampicillin, amoxicillin, metronidazole, erythromycin, clarithromycin and doxycycline in the absence and the presence of PAßN against 32 selected MDR isolates.

Results

Overall H. pylori resistance rate was 100% to ampicillin, penicillin and co-amoxiclav; 97.14% to amoxicillin, 97.85% to metronidazole, 47.85% to erythromycin, 13.57% to clarithromycin; 5, 2.86 and 0.71% to doxycycline, tetracycline and minocycline respectively. No resistance to azithromycin, rifabutin, imipenem, ciprofloxacin, norfloxacin and levofloxacin was detected among H. pylori isolates. Seventy percent (70%) of the tested isolates elicited a multiple drugs resistance pattern; 42.57% double, 15.71% triple and 5.71% quadruple drugs resistance. Metronidazole and amoxicillin were more concerned with double resistance pattern (86.76%). The spectrum of activity recorded with metronidazole, doxycycline, clarithromycin and erythromycin ranged from 0 to 100% in the absence to the presence of PAßN against the tested MDR isolates. An 8 to 128-fold increase in potency was also noticed with these antibiotics in the presence of PAßN.

Conclusion

With regard to the high resistance rate to both amoxicillin and metronidazole, these drugs should be avoided as components of triple therapy in our milieu. In contrast, ciprofloxacin, norfloxacin, levofloxacin and tetracyclines could be used to achieve a better eradication rate and to reduce the risk of selection of H. pylori resistant strains.

N-Arylations of trifluoromethylated N-acylhydrazones with diaryliodonium salts as arylation reagents

A novel and efficient N-arylation of trifluoromethylated N-acylhydrazones is described by using diaryliodonium salts as arylation reagents in the presence of copper salts. A wide variety of N-aryl acylhydrazones are obtained with good to excellent yields under mild reaction conditions.

Efficacy and Tolerability of Two Quadruple Regimens: Bismuth, Omeprazole, Metronidazole with Amoxicillin or Tetracycline as First-Line Treatment for Eradication of Helicobacter Pylori in Patients with Duodenal Ulcer: A Randomized Clinical Trial

AIM

To evaluate the efficacy and tolerability of tetracycline vs. high-dose amoxicillin in bismuth-based quadruple therapy for Helicobacter pylori(H. pylori) eradication.

METHODS

This randomized, open-label clinical trial included 228 patients with H.pylori infection and duodenal ulcer without a history of H.pylori treatment. Patients were randomly divided into two groups. The amoxicillin group received metronidazole 500mg, bismuth subcitrate 240mg, and amoxicillin 1000mg, all three times a day, plus omeprazole 20 mg twice a day, for 14 days. The tetracycline group received metronidazole 500mg three times a day; bismuth subcitrate240mg and tetracycline HCl 500mg, both four times a day; and omeprazole 20 mg twice a day, for 14 days. Evaluation for compliance and drug-relatedadverse effects were evaluated at the end of two weeks. Eight weeks after the end of treatment, the rate of H.pylori eradication was assessed by the C13urease breath test.

RESULTS

There were no significant demographic differences between the two groups. Eradication rate was higher with the amoxicillin-containing regimen than the tetracycline-containing regimen: 105/110 (95.51%; 95% confidence interval, 91.5%-99.3%) vs. 88/105 (83.8%; 95%CI, 76.7%-90.8%) by per-protocol analysis (p = 0.005) and 92.9% (95%CI, 88.1%-97.6%) vs. 76.5% (95%CI, 68.7%-84.2%) by intention-to-treat analysis (ITT, p = 0.001). Adverse effects were significant higher in the tetracycline groupthan in the amoxicillin group (65.2% vs. 43.4%; p = 0.001).

CONCLUSION

Bismuth-based quadruple therapy including high-dose amoxicillin and metronidazole achieved an acceptable rate of H.pylori infection eradication with good tolerance in patients with duodenal ulcer. This regimen can overcome treatment resistance in areas with high prevalence of metronidazole and clarithromycin resistance.

TRIAL REGISTRATION

The Thai Clinical Trial Registry (TCTR) 20170623004.

Signal Detection of Adverse Drug Reaction of Amoxicillin Using the Korea Adverse Event Reporting System Database

We conducted pharmacovigilance data mining for a β-lactam antibiotics, amoxicillin, and compare the adverse events (AEs) with the drug labels of 9 countries including Korea, USA, UK, Japan, Germany, Swiss, Italy, France, and Laos. We used the Korea Adverse Event Reporting System (KAERS) database, a nationwide database of AE reports, between December 1988 and June 2014. Frequentist and Bayesian methods were used to calculate disproportionality distribution of drug-AE pairs. The AE which was detected by all the three indices of proportional reporting ratio (PRR), reporting odds ratio (ROR), and information component (IC) was defined as a signal. The KAERS database contained a total of 807,582 AE reports, among which 1,722 reports were attributed to amoxicillin. Among the 192,510 antibiotics-AE pairs, the number of amoxicillin-AE pairs was 2,913. Among 241 AEs, 52 adverse events were detected as amoxicillin signals. Comparing the drug labels of 9 countries, 12 adverse events including ineffective medicine, bronchitis, rhinitis, sinusitis, dry mouth, gastroesophageal reflux, hypercholesterolemia, gastric carcinoma, abnormal crying, induration, pulmonary carcinoma, and influenza-like symptoms were not listed on any of the labels of nine countries. In conclusion, we detected 12 new signals of amoxicillin which were not listed on the labels of 9 countries. Therefore, it should be followed by signal evaluation including causal association, clinical significance, and preventability.

Emerging antimicrobial resistance pattern of Helicobacter pylori in central Gujarat

BACKGROUND

Antimicrobial resistance is a growing problem in H. pylori treatment. The study was intended to evaluate the prevalence of resistance amongst 80 H.pylori isolates cultured from biopsy taken during routine endoscopies in 2008-2011.

MATERIALS AND METHODS

855 gastro duodenal biopsies were collected and cultured on H.pylori selective medium (containing Brucella agar and Columbia agar (Hi media), with Skirrow's supplement (antibiotic supplement) and 7% human blood cells). H.pylori was isolated from 80 specimens. The antimicrobial susceptibility of H.pylori isolates was carried out by the Kirby Bauer technique against metronidazole (5 µg), clarithromycin (15 µg), ciprofloxacin (5 µg), amoxicillin (10 µg), tetracycline (30 µg), erythromycin (15 µg), levofloxacin (5 µg), and furazolidone (50 µg) (Sigma- Aldrich, MO).

RESULTS

83.8% isolates were resistant to metronidazole, 58.8% were resistant to Clarithromycin 72.5% were resistant to Amoxicillin, 50% to Ciprofloxacin and 53.8% to tetracycline. furazolidone, erythromycin and Levofloxacin showed only 13.8% resistance to H.pylori. Multi drug resistance with metronidazole+clarithromycin+tetracycline was 85%. For all the drugs Antimicrobial resistance rate was found higher in males compare to females. Metronidazole and amoxicillin resistance was found noteworthy in patients with duodenal ulcer (p=0.018), gastritis (P=0.00), and in reflux esophagitis (P=0.00). clarithromycin and tetracycline resistance was suggestively linked with duodenitis (P=0.018), while furazolidone, erythromycin and levofloxacin showed excellent sensitivity in patients with duodenitis (P value--0.018), gastritis (P=0.00) and reflux esophagitis (P=0.00). Resistance with metronidazole (P=0.481), clarithromycin (P=0.261), amoxicillin (P=0.276), tetracycline (P=0.356), ciprofloxacin (P=0.164) was not correlated well with Age-group and Gender of the patients.

CONCLUSION

A very high percentage of patients were infected with metronidazole and clarithromycin resistant strains. The use of antibiotics for other indications seems to be the major risk factor for the development of primary resistance. High incidence should alarm the gastroenterologist while prescribing the eradication regimen.

Standard Triple Therapy versus Sequential Therapy in Helicobacter pylori Eradication: A Double-Blind, Randomized, and Controlled Trial

Aim. To compare 10-day standard triple therapy versus sequential therapy as first-line treatment in patients infected with H. pylori. Methods. One hundred H. pylori positive patients (diagnosed by rapid urease test and histology), with average age of 47.2, M/F = 28/72, were randomized to receive either standard triple treatment (TT) as follows: lansoprazole 30 mg, clarithromycin 500 mg, and amoxicillin 1 g, b.i.d. for ten days, or sequential treatment (ST) as follows: lansoprazole 30 mg, amoxicillin and placebo 1.0 g b.i.d for the first five days, followed by lansoprazole 30 mg, clarithromycin 500 mg, and tinidazole 500 mg b.i.d, for the remaining five days. Eradication rates were determined 60 days after treatment by urease, histology, or ¹³C-urea breath test. Results. In intention to treat (ITT) analysis, the rate of H. pylori eradication in the TT and ST groups was the same for both regimens as follows: 86% (43/50), 95% CI 93,3 to 73.4%. In Per protocol (PP) analysis, the rate of H. pylori eradication in the TT and ST groups was 87.8% (43/49), 95% CI 94,5 to 75.3% and 89.6% (43/48), 95% CI 95,8 to 77.3%, respectively. Conclusions. In Brazil, standard triple therapy is as equally effective as sequential therapy in eradicating Helicobacter pylori patients. This study was registered under Clinical Trials with number ISRCTN62400496.

Efficacy of levofloxacin, amoxicillin and a proton pump inhibitor in the eradication of Helicobacter pylori in Brazilian patients with peptic ulcers

OBJECTIVES

The eradication of Helicobacter (H.) pylori allows peptic ulcers in patients infected with the bacteria to be cured. Treatment with the classic triple regimen (proton pump inhibitor, amoxicillin and clarithromycin) has shown decreased efficacy due to increased bacterial resistance to clarithromycin. In our country, the eradication rate by intention to treat with this regimen is 83%. In Brazil, a commercially available regimen for bacterial eradication that uses levofloxacin and amoxicillin with lansoprazole is available; however, its efficacy is not known. Considering that such a treatment may be an alternative to the classic regimen, we aimed to verify its efficacy in H. pylori eradication.

METHODS

Patients with peptic ulcer disease infected with H. pylori who had not received prior treatment were treated with the following regimen: 30 mg lansoprazole bid, 1,000 mg amoxicillin bid and 500 mg levofloxacin, once a day for 7 days.

RESULTS

A total of 66 patients were evaluated. The patients' mean age was 52 years, and women comprised 55% of the sample. Duodenal ulcers were present in 50% of cases, and gastric ulcers were present in 30%. The eradication rate was 74% per protocol and 73% by intention to treat. Adverse effects were reported by 49 patients (74%) and were mild to moderate, with a prevalence of diarrhea complaints.

CONCLUSIONS

Triple therapy comprising lansoprazole, amoxicillin and levofloxacin for 7 days for the eradication of H. pylori in Brazilian peptic ulcer patients showed a lower efficacy than that of the classic triple regimen.

Antimicrobial susceptibility testing for Helicobacter pylori isolates from Brazilian children and adolescents: comparing agar dilution, E-test, and disk diffusion

Antimicrobial susceptibility testing for Helicobacter pylori is increasingly important due to resistance to the most used antimicrobials agents. Only agar dilution method is approved by CLSI, but it is difficult to perform routinely. We evaluated the reliability of E-test and disk diffusion comparing to agar dilution method on Helicobacter pylori antimicrobial susceptibility testing. Susceptibility testing was performed for amoxicillin, clarithromycin, furazolidone, metronidazole and tetracycline using E-test, disk-diffusion and agar dilution method in 77 consecutive Helicobacter pylori strains from dyspeptic children and adolescents. Resistance rates were: amoxicillin - 10.4%, 9% and 68.8%; clarithromycin - 19.5%, 20.8%, 36.3%; metronidazole - 40.2%33.7%, 38.9%, respectively by agar dilution, E-test and disk diffusion method. Furazolidone and tetracycline showed no resistance rates. Metronidazole presented strong correlation to E-test (r = 0.7992, p < 0.0001) and disk diffusion method (r=-0.6962, p < 0.0001). Clarithromycin presented moderate correlation to E-test (r = 0.6369, p < 0.0001) and disk diffusion method (r=−0.5656, p < 0.0001). Amoxicillin presented weak correlation to E-test (r = 0.3565, p = 0.0015) and disk diffusion (r=−0.3565, p = 0.0015). Tetracycline presented weak correlation with E-test (r = 0.2346, p = 0.04) and furazolidone to disk diffusion (r=−0.0288, p = 0.8038). E-test presented better agreement with gold standard. It is an easy and reliable method for Helicobacter pylori susceptibility testing. Disk diffusion method presented high disagreement and high rates of major errors.

Resistance to amoxicillin, clarithromycin and ciprofloxacin of Helicobacter pylori isolated from Southern Brazil patients

Introduction:Helicobacter pylori is a bacteria which infects half the world population and is an important cause of gastric cancer. The eradication therapy is not always effective because resistance to antimicrobials may occur. The aim of this study was to determine the susceptibility profile of H. pylori to amoxicillin, clarithromycin and ciprofloxacin in the population of Southern Brazil.

Material and methods: Fifty four samples of H. pylori were evaluated. The antibiotics susceptibility was determined according to the guidelines of the British Society for Antimicrobial Chemotherapy and the Comité de l'Antibiogramme de la Société Française de Microbiologie.

Results: Six (11.1%) H. pylori isolates were resistant to clarithromycin, one (1.9%) to amoxicillin and three (5.5%) to ciprofloxacin. These indices of resistance are considered satisfactory and show that all of these antibiotics can be used in the empirical therapy.

Conclusion: The antibiotics amoxicillin and clarithromycin are still a good option for first line anti-H. pylori treatment in the population of Southern Brazil.

Treatment of Helicobacter pylori infection: current status and future concepts

Helicobacter pylori (H. pylori) infection is highly associated with the occurrence of gastrointestinal diseases, including gastric inflammation, peptic ulcer, gastric cancer, and gastric mucosa-associated lymphoid-tissue lymphoma. Although alternative therapies, including phytomedicines and probiotics, have been used to improve eradication, current treatment still relies on a combination of antimicrobial agents, such as amoxicillin, clarithromycin, metronidazole, and levofloxacin, and antisecretory agents, such as proton pump inhibitors (PPIs). A standard triple therapy consisting of a PPI and two antibiotics (clarithromycin and amoxicillin/metronidazole) is widely used as the first-line regimen for treatment of infection, but the increased resistance of H. pylori to clarithromycin and metronidazole has significantly reduced the eradication rate using this therapy and bismuth-containing therapy or 10-d sequential therapy has therefore been proposed to replace standard triple therapy. Alternatively, levofloxacin-based triple therapy can be used as rescue therapy for H. pylori infection after failure of first-line therapy. The increase in resistance to antibiotics, including levofloxacin, may limit the applicability of such regimens. However, since resistance of H. pylori to amoxicillin is generally low, an optimized high dose dual therapy consisting of a PPI and amoxicillin can be an effective first-line or rescue therapy. In addition, the concomitant use of alternative medicine has the potential to provide additive or synergistic effects against H. pylori infection, though its efficacy needs to be verified in clinical studies.

Low Helicobacter pylori primary resistance to clarithromycin in gastric biopsy specimens from dyspeptic patients of a city in the interior of São Paulo, Brazil

BACKGROUND

Clarithromycin, amoxicillin, and a pump proton inhibitor are the most common drugs recommended as first-line triple therapy for H.pylori treatment, which results in eradication rates close to 80%, varying regionally, principally due to emergency cases and increases of clarithromycin resistant strains. Nucleotide substitutions at the H. pylori domain V of the 23S rRNA fraction are involved in the macrolide resistance and the A2142G and A2143G mutations are predominant in clinical isolates worldwide including in Brazil. As H. pylori culture is fastidious, we investigated the primary occurrence of H. pylori A2142G and A2143G rDNA 23S mutations using a molecular approach directly on gastric biopsies of dyspeptic patients consecutively attended at Hospital das Clinicas of Marilia, São Paulo, Brazil.

METHODS

Biopsy specimens obtained from 1137 dyspeptic patients, were subjected to histopathology and H. pylori diagnosis by histology and PCR. PCR/RFLP assay was used to detect A2142G and A2143G point mutations at domain V of the H. pylori 23S rDNA associated with clarithromycin resistance. Through the developed assay, a 768 bp PCR amplicon corresponding to1728 to 2495 bp of the 23S H. pylori rDNA is restricted with MboII for A2142G mutation detection and with BsaI for A2143G mutation detection. Occurrence of 23S rDNA A2142G results in two DNA fragments (418 and 350 bp) and of 23S rDNA A2143G results in three DNA fragments (108, 310 and 350pb), due to a conserved BsaI restriction site.

RESULTS

The PCR method used to diagnose H. pylori presented sensitivity, specificity and accuracy of 77,6%, 79,3% and 78,6%, respectively, compared to histology, the gold standard method for H. pylori diagnosis used in our routine. Prevalence of H.pylori with clarithromycin resistant genotypes was 2,46%, with predominance of A2143G 23S rDNA point mutation.

CONCLUSIONS

The PCR/RFLP assay was a rapid and accurate H.pylori diagnostic and clarithromycin resistance determination method useful for routine practice. As prevalence of primary resistance of H.pylori to clarithromycin due to A2142G and A2143G mutations remains low in Marilia, the standard clarithromycin containing triple therapy is still valid.

Substitutions in penicillin-binding protein 1 in amoxicillin-resistant Helicobacter pylori strains isolated from Korean patients

Background/Aims

A worldwide increase in amoxicillin resistance in Helicobacter pylori is having an adverse effect on eradication therapy. In this study, we investigated the mechanism of the amoxicillin resistance of H. pylori in terms of amino acid substitutions in penicillin-binding protein 1 (PBP1).

Methods

In total, 150 H. pylori strains were isolated from 144 patients with chronic gastritis, peptic ulcers, or stomach cancer. The minimum inhibitory concentrations (MICs) of the strains were determined with a serial 2-fold agar dilution method. The resistance breakpoint for amoxicillin was defined as >0.5 µg/mL.

Results

Nine of 150 H. pylori strains showed amoxicillin resistance (6%). The MIC values of the resistant strains ranged from 1 to 4 µg/mL. A PBP1 sequence analysis of the resistant strains revealed multiple amino acid substitutions: Val16→Ile, Val45→Ile, Ser414→Arg, Asn562→Tyr, Thr593→Ala, Gly595→Ser, and Ala599→Thr. The natural transformation of these mutated genes into amoxicillin-sensitive strains was performed in two separate pbp1 gene segments. A moderate increase in the amoxicillin MIC was observed in the segment that contained the penicillin-binding motif of the C-terminal portion, the transpeptidase domain.

Conclusions

pbp1 mutation affects the amoxicillin resistance of H. pylori through the transfer of the penicillin-binding motif.

High Helicobacter pylori resistance to metronidazole and clarithromycin in Brazilian children and adolescents

OBJECTIVE

The aim of the present study was to assess the primary and secondary resistance of Helicobacter pylori strains to clarithromycin, amoxicillin, furazolidone, tetracycline, and metronidazole, the conventional antibiotics presently used in Brazilian children and adolescents.

METHODS

Seventy-seven consecutive H pylori strains, 71 of 77 strains obtained from patients without previous eradication treatment for H pylori infection, and 6 strains from patients in whom previous eradication treatment had failed.

RESULTS

Global rate of resistance was 49.3% (38/77): 40% of strains were resistant to metronidazole, 19.5% to clarithromycin, and 10.4% to amoxicillin. All of the tested H pylori strains were susceptible to furazolidone and tetracycline. Multiple resistance were detected in 18.2% (14/77 patients) of the strains: 6 of 14 (43%) simultaneously resistant to clarithromycin and metronidazole; 5 of 14 (36%) to amoxicillin and metronidazole; 2 of 14 (14%) to amoxicillin, clarithromycin, and metronidazole; and 1 of 14 (7%) to clarithromycin and amoxicillin.

CONCLUSIONS

The high resistance rate to metronidazole and clarithromycin observed in clinical H pylori isolates can exclude these antimicrobials in empirical eradication treatment in Brazil. Otherwise, furazolidone and tetracycline presented no resistance. Properly assessing the risks and benefits, these 2 antimicrobials and their derivatives could be used in empirical eradication schedules, both associated with amoxicillin, which showed a low resistance rate despite its wide use in pediatric patients.

Association of a probiotic to a Helicobacter pylori eradication regimen does not increase efficacy or decreases the adverse effects of the treatment: a prospective, randomized, double-blind, placebo-controlled study

Background

The treatment for the eradication of Helicobacter pylori (H. pylori) is complex; full effectiveness is rarely achieved and it has many adverse effects. In developing countries, increased resistance to antibiotics and its cost make eradication more difficult. Probiotics can reduce adverse effects and improve the infection treatment efficacy.

If the first-line therapy fails a second-line treatment using tetracycline, furazolidone and proton-pump inhibitors has been effective and low cost in Brazil; however it implies in a lot of adverse effects. The aim of this study was to minimize the adverse effects and increase the eradication rate applying the association of a probiotic compound to second-line therapy regimen.

Methods

Patients with peptic ulcer or functional dyspepsia infected by H. pylori were randomized to treatment with the furazolidone, tetracycline and lansoprazole regimen, twice a day for 7 days. In a double-blind study, patients received placebo or a probiotic compound (Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium bifidum and Streptococcus faecium) in capsules, twice a day for 30 days. A symptom questionnaire was administered in day zero, after completion of antibiotic therapy, after the probiotic use and eight weeks after the end of the treatment. Upper digestive endoscopy, histological assessment, rapid urease test and breath test were performed before and eight weeks after eradication treatment.

Results

One hundred and seven patients were enrolled: 21 men with active probiotic and 19 with placebo plus 34 women with active probiotic and 33 with placebo comprising a total of 55 patients with active probiotic and 52 with placebo. Fifty-one patients had peptic ulcer and 56 were diagnosed as functional dyspepsia. The per-protocol eradication rate with active probiotic was 89.8% and with placebo, 85.1% (p = 0.49); per intention to treat, 81.8% and 79.6%, respectively (p = 0.53). The rate of adverse effects at 7 days with the active probiotic was 59.3% and 71.2% with placebo (p = 0.20). At 30 days, it was 44.9% and 60.4%, respectively (p = 0.08).

Conclusions

The use of this probiotic compound compared to placebo in the proposed regimen in Brazilian patients with peptic ulcer or functional dyspepsia showed no significant difference in efficacy or adverse effects.

Trial registration

Current Controlled Trials ISRCTN04714018

Association of a probiotic to a Helicobacter pylori eradication regimen does not increase efficacy or decreases the adverse effects of the treatment: a prospective, randomized, double-blind, placebo-controlled study

Internet websites are a resource for patients seeking information about probiotics. We examined a sample of 71 websites presenting probiotic information. We found that descriptions of benefits far outnumbered descriptions of risks and commercial websites presented significantly fewer risks than noncommercial websites. The bias towards the presentation of therapeutic benefits in online content suggests that patients are likely interested in using probiotics and may have unrealistic expectations for therapeutic benefit. Gastroenterologists may find it useful to initiate conversations about probiotics within the context of a comprehensive health management plan and should seek to establish realistic therapeutic expectations with their patients.

Helicobacter pylori eradication in Western Australia using novel quadruple therapy combinations

BACKGROUND

Helicobacter pylori eradication rates with standard triple therapy are declining worldwide. The optimal management of H. pylori is evolving and new treatment combinations for antibiotic resistant H. pylori strains are required, especially for patients with penicillin allergy.

AIM

To review the effectiveness of alternative antibiotic combinations and necessity of pre-antibiotic sensitivity testing.

METHODS

A total of 310 consecutive patients who had failed at least one course of standard 7-day triple therapy initially prescribed by their physicians were included in this study between year 2007 and 2011. Antibiotics were prescribed based on pre-antibiotic sensitivity tests and, if any, patient's allergy to penicillin.

RESULTS

In 98.7% of the patients' samples, H. pylori was successfully cultured. The proportion resistant to clarithromycin and metronidazole was 94.1% and 67.6% respectively, with 65% resistant to both. For the in-house primary quadruple therapy, with Proton pump inhibitor, Amoxicillin, Rifabutin and Ciprofloxacin (PARC), H. pylori was successfully eradicated in 95.2% of patients. For patients allergic to amoxicillin, an alternative quadruple therapy using Proton pump inhibitor, Bismuth subcitrate, Rifabutin and Ciprofloxacin (PBRC) gave an eradication rate of 94.2%. Patients needing alternative salvage therapy were given novel personalised combinations consisting of bismuth, rifabutin, tetracycline or furazolidone; the eradication rate was 73.8%.

CONCLUSIONS

Patients who present with antibiotic resistant H. pylori can be confidently treated with PARC, PBRC or other personalised salvage therapies. These regimens can be used when treatment options are limited by penicillin allergy. Pre-treatment H. pylori antibiotic sensitivity tests contributed to the high eradication rate in this study.

Recent Insights into Antibiotic Resistance in Helicobacter pylori Eradication

Antibiotics have been useful in the treatment of H. pylori-related benign and malignant gastroduodenal diseases. However, emergence of antibiotic resistance often decreases the eradication rates of H. pylori infections. Many factors have been implicated as causes of treatment failure, but the main antibiotic resistance mechanisms described to date are due to point mutations on the bacterial chromosome, a consequence of a significantly phenotypic variation in H. pylori. The prevalence of antibiotic (e.g., clarithromycin, metronidazole, tetracycline, amoxicillin, and furazolidone) resistance varies among different countries; it appears to be partly determined by geographical factors. Since the worldwide increase in the rate of antibiotic resistance represents a problem of relevance, some studies have been performed in order to identify highly active and well-tolerated anti-H. pylori therapies including sequential, concomitant quadruple, hybrid, and quadruple therapy. These represent a promising alternatives in the effort to overcome the problem of resistance. The aim of this paper is to review the current status of antibiotic resistance in H. pylori eradication, highlighting the evolutionary processes in detail at alternative approaches to treatment in the past decade. The underlying resistance mechanisms will be also followed.

Anti-Helicobacter pylori potential of artemisinin and its derivatives

The antimalarial drug artemisinin from Artemisia annua demonstrated remarkably strong activity against Helicobacter pylori, the pathogen responsible for peptic ulcer diseases. In an effort to develop a novel antimicrobial chemotherapeutic agent containing such a sesquiterpene lactone endoperoxide, a series of analogues (2 natural and 15 semisynthetic molecules), including eight newly synthesized compounds, were investigated against clinical and standard strains of H. pylori. The antimicrobial spectrum against 10 H. pylori strains and a few other bacterial and fungal strains indicated specificity against the ulcer causing organism. Of five promising molecules, a newly synthesized ether derivative β-artecyclopropylmether was found to be the most potent compound, which exhibited MIC range, MIC(90), and minimum bactericidal concentration range values of 0.25 to 1.0 μg/ml, 1.0 μg/ml, and 1 to 16 μg/ml, respectively, against both resistant and sensitive strains of H. pylori. The molecule demonstrated strong bactericidal kinetics with extensive morphological degeneration, retained functional efficacy at stomach acidic pH unlike clarithromycin, did not elicit drug resistance unlike metronidazole, and imparted sensitivity to resistant strains. It is not cytotoxic and exhibits in vivo potentiality to reduce the H. pylori burden in a chronic infection model. Thus, β-artecyclopropylmether could be a lead candidate for anti-H. pylori therapeutics. Since the recurrence of gastroduodenal ulcers is believed to be mainly due to antibiotic resistance of the commensal organism H. pylori, development of a candidate drug from this finding is warranted.

Absence of Helicobacter pylori high tetracycline resistant 16S rDNA AGA926-928TTC genotype in gastric biopsy specimens from dyspeptic patients of a city in the interior of São Paulo, Brazil

Background

Treatment effectiveness of Helicobacter pylori varies regionally and is decreasing worldwide, principally as a result of antibiotic resistant bacterium. Tetracycline is generally included in second line H. pylori eradication regimens. In Brazil, a high level of tetracycline resistance (TetR) is mainly associated with AGA926-928TTC 16 S rDNA nucleotide substitutions. As H. pylori culture is fastidious, we investigated the primary occurrence of H. pylori 16 S rDNA high level TetR genotype using a molecular approach directly on gastric biopsies of dyspeptic patients attending consecutively at Hospital das Clinicas of Marilia, São Paulo, Brazil.

Methods

Gastric biopsy specimens of 68 peptic ulcer disease (PUD) and 327 chronic gastritis (CG) patients with a positive histological diagnosis of H. pylori were investigated for TetR 16 S rDNA genotype through a molecular assay based on amplification of a 16 S rDNA 545 bp fragment by polymerase chain reaction and HinfI restriction fragment length polymorphism (PCR/RFLP). Through this assay, AGA926-928TTC 16 S rDNA TetR genotype resulted in a three DNA fragment restriction pattern (281, 227 and 37 bp) and its absence originated two DNA fragments (264 and 281 bp) due to a 16 S rDNA conserved Hinf I restriction site.

Results

The 545 bp 16 S rDNA PCR fragment was amplified from 90% of gastric biopsies from histological H. pylori positive patients. HinfI RFLP revealed absence of the AGA926–928TTC H. pylori genotype and PCR products of two patients showed absence of the conserved 16 S rDNA HinfI restriction site. BLASTN sequence analysis of four amplicons (two conserved and two with an unpredicted HinfI restriction pattern) revealed a 99% homology to H. pylori 16 S rDNA from African, North and South American bacterial isolates. A nucleotide substitution abolished the conserved HinfI restriction site in the two PCR fragments with unpredicted HinfI RFLP, resulting in an EcoRI restriction site.

Conclusions

H. pylori AGA926-928TTC 16 S rDNA gene substitutions were not found in our population. More research is required to investigate if H. pylori TetR has a different genetic background in our region and if the nucleotide substitutions of the uncultured H. pylori 16 S rRNA partial sequences have biological significance.

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.

Application of real-time PCR stool assay for Helicobacter pylori detection and clarithromycin susceptibility testing in Brazilian children

BACKGROUND

Helicobacter pylori ClariRes assay is a novel commercially available real-time PCR assay allowing H. pylori detection and clarithromycin susceptibility testing in either gastric biopsy or stool specimens.

OBJECTIVE

The aim of this study was to validate the novel biprobe real-time assay in stool specimens from 217 dyspeptic children.

METHODS

DNA from gastric biopsies and stool specimens were obtained and submitted to the biprobe real time assay for H. pylori detection and clarithromycin susceptibility testing.

RESULTS

The sensitivity, specificity, and test accuracy were 69, 100 and 93.9% for the detection of H. pylori infection and 83.3, 100 and 95.6%, for detection of clarithromycin resistance.

CONCLUSION

This assay proved to be appropriate for H. pylori clarithromycin susceptibility testing, particularly in children populations where a high prevalence of clarithromycin-resistant strains is suspected.

Antimicrobial activity of Northwestern Mexican plants against Helicobacter pylori

Helicobacter pylori is the major etiologic agent of such gastric disorders as chronic active gastritis and gastric carcinoma. Over the past few years, the appearance of antibiotic-resistant bacteria has led to the development of better treatments, such as the use of natural products. This study evaluated the anti-H. pylori activity of 17 Mexican plants used mainly in the northwestern part of Mexico (Sonora) for the empirical treatment of gastrointestinal disorders. The anti-H. pylori activity of methanolic extracts of the plants was determined by using the broth microdilution method. The 50% minimum inhibitory concentrations ranged from less than 200 to 400 μg/mL for Castella tortuosa, Amphipterygium adstringens, Ibervillea sonorae, Pscalium decompositum, Krameria erecta, Selaginella lepidophylla, Pimpinella anisum, Marrubium vulgare, Ambrosia confertiflora, and Couterea latiflora and were greater than 800 μg/mL for Byophyllum pinnatum, Tecoma stans linnaeus, Kohleria deppena, Jatropha cuneata, Chenopodium ambrosoides, and Taxodium macronatum. Only Equisetum gigantum showed no activity against H. pylori. This study suggests the important role that these plants may have in the treatment of gastrointestinal disorders caused by H. pylori. The findings set the groundwork for further characterization and elucidation of the active compounds responsible for such activity.

Sequential metronidazole-furazolidone or clarithromycin-furazolidone compared to clarithromycin-based quadruple regimens for the eradication of Helicobacter pylori in peptic ulcer disease: a double-blind randomized controlled trial

BACKGROUND

Furazolidone is a much cheaper drug with a very low resistance against Helicobacter pylori compared to clarithromycin. We aim to evaluate safety and efficacy of a sequential furazolidone-based regimen versus clarithromycin-based therapy in H. pylori eradication for ulcer disease.

MATERIALS

Patients with proven peptic ulcer or duodenitis were randomized into three groups: OAB-M-F; metronidazole (M) (500 mg bid) for the first 5 days, followed by furazolidone (F) (200 mg bid) for the second 5 days; OAC-P; clarithromycin (C) (500 mg bid) for 10 days; and OAB-C-F; clarithromycin (500 mg bid) for the first 5 days and furazolidone (200 mg bid) for the second 5 days. All groups received omeprazole (O) (20 mg bid) and amoxicillin (A) (1 g bid). Groups OAB-M-F and OAB-C-F were also given bismuth subcitrate (B) (240 mg bid), whereas a placebo (P) was given to group OAC-P. Adverse events were scored and recorded. Two months after treatment, a C(13) -urea breath test was performed.

RESULTS

Three hundred and ten patients were enrolled and 92 (OAB-M-F), 95 (OAC-P), and 98 (OAB-C-F) completed the study. The intention-to-treat eradication rates were 78.5% (95% CI = 69-85), 81.1% (95% CI = 73-88), and 82% (95% CI = 74-89), and per-protocol eradication rates were 91.3% (95% CI = 83-96), 90.4% (95% CI = 82-95), and 88.7% (95% CI = 81-94), for group OAB-M-F, OAC-P, and OAB-C-F, respectively. Eradication rate differences did not reach statistical significance. The most common adverse event, bad taste, occurred in all groups, but more frequently in groups OAC-P (34%) and OAB-C-F (32%), than OAB-M-F (14%) (p < .05). Adverse symptoms score were 0.88 ± 2.05 in group OAB-M-F, 1.15 ± 1.40 in group OAC-P, and 1.87 ± 1.62 in group OAB-C-F.

CONCLUSION

Furazolidone can replace clarithromycin in H. pylori eradication regimens because of lack of development of resistance and very low cost.

Comparison of the efficacy of triple versus quadruple therapy on the eradication of Helicobacter pylori and antibiotic resistance

OBJECTIVE

Our aim was to compare the efficacy and safety of Helicobacter pylori (H. pylori) eradication with pantoprazole-based 7-day standard triple therapy (PAC) and 10-day quadruple therapy (PBMT), and to study the primary resistance of H. pylori to amoxicillin, clarithromycin, metronidazole and tetracycline.

METHODS

A total of 170 patients with non-ulcer dyspepsia (NUD) and H. pylori infection were allocated to two study groups. The PAC group received pantoprazole 40 mg b.i.d., amoxicillin 1.0 g b.i.d. and clarithromycin 500 mg b.i.d. for 7 days; the PBMT group received pantoprazole 40 mg b.i.d., colloidal bismuth subcitrate 220 mg b.i.d, metronidazole 400 mg t.i.d. and tetracycline 750 mg b.i.d. for 10 days. A total of 80 H. pylori strains were isolated and antibiotic resistance was measured by the agar dilution method.

RESULTS

A total of 166 patients completed the therapy. The intention-to-treat eradication rates in the PAC and PBMT groups were 63.5% and 89.4%, respectively (P < 0.05). By per protocol analysis, the eradication rates of the two groups were 65.1% and 91.6%, respectively (P < 0.05). Overall 77 clinical isolated H. pylori strains were cultured successfully. The H. pylori primary resistance rates to metronidazole and clarithromycin were 41.6% and 20.8%, respectively, whereas all the H. pylori isolates were sensitive to amoxicillin and tetracycline.

CONCLUSION

The efficacy of PAC declines in many regions in China because of high antibiotic resistance rates. The PBMT regimen achieved a high eradication rate of H. pylori and might be used as a first-line therapy.

High prevalence of clarithromycin resistance and cagA, vacA, iceA2, and babA2 genotypes of Helicobacter pylori in Brazilian children

We isolated 45 Helicobacter pylori strains from 217 child patients. Resistance to clarithromycin, metronidazole, amoxicillin, and tetracycline was detected in 27%, 13%, 4%, and 0% of strains, respectively. The A2143G mutation was the most prevalent (67%) among clarithromycin-resistant strains. In addition, strain genotyping revealed a significant association between gastritis severity and the simultaneous presence of cagA, vacA s1m1, iceA2, and babA2 genes.

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.

Helicobacter pylori eradication therapy

Helicobacter pylori infection is the main cause of gastritis, gastroduodenal ulcers and gastric cancer. H. pylori eradication has been shown to have a prophylactic effect against gastric cancer. According to several international guidelines, the first-line therapy for treating H. pylori infection consists of a proton pump inhibitor (PPI) or ranitidine bismuth citrate, with any two antibiotics among amoxicillin, clarithromycin and metronidazole, given for 7-14 days. However, even with these recommended regimens, H. pylori eradication failure is still seen in more than 20% of patients. The failure rate for first-line therapy may be higher in actual clinical practice, owing to the indiscriminate use of antibiotics. The recommended second-line therapy is a quadruple regimen composed of tetracycline, metronidazole, a bismuth salt and a PPI. The combination of PPI-amoxicillin-levofloxacin is a good option as second-line therapy. In the case of failure of second-line therapy, the patients should be evaluated using a case-by-case approach. European guidelines recommend culture before the selection of a third-line treatment based on the microbial antibiotic sensitivity. H. pylori isolates after two eradication failures are often resistant to both metronidazole and clarithromycin. The alternative candidates for third-line therapy are quinolones, tetracycline, rifabutin and furazolidone; high-dose PPI/amoxicillin therapy might also be promising.

Anti-Helicobacter pylori activity of plant extracts traditionally used for the treatment of gastrointestinal disorders

The antibacterial activity of plant extracts obtained from Bixa orellana L., Chamomilla recutita L., Ilex paraguariensis A. St.-Hil., Malva sylvestris L., Plantago major L. and Rheum rhaponticum L. has been evaluated against two reference strains and eleven clinical isolates of Helicobacter pylori. All the plant species chosen are used in popular Brazilian cuisine and folk medicine in the treatment of gastrointestinal disorders. Initial screening was made by the disk diffusion test and then minimum inhibitory concentration was determined by the agar dilution method. The results presented in this work demonstrated that among the plant preparations analyzed, B. orellana L., C. recutita L., I. paraguariensis A. St.-Hil. and M. sylvestris L. were capable of inhibiting the in vitro growth of H. pylori.

Effect of resveratrol on Helicobacter pylori-induced interleukin-8 secretion, reactive oxygen species generation and morphological changes in human gastric epithelial cells

Inflammatory cytokine interleukin-8 (IL-8) and reactive oxygen species (ROS) overexpressed in the gastric mucosa when exposed to Helicobacter pylori, defined as a class I carcinogen. Moreover, infection with H. pylori leads to morphological changes in co-cultured cells known as hummingbird phenomenon along with increased motility. Resveratrol, a highly abundant polyphenol in red grapes, has shown anti-inflammatory, anti-cancer, cardioprotective and neuroprotective activities. However, the effect of resveratrol in H. pylori-infected cells has not been investigated. The present study was, therefore, aimed to evaluate the effect of resveratrol on the induction of IL-8, ROS and hummingbird morphology in H. pylori-infected gastric epithelial cells. The non-toxic concentration of resveratrol for both H. pylori and epithelial cells was determined by brucella broth dilution method and DNA fragmentation assay. The non-toxic resveratrol (< or =100 microM) treatment did not demonstrate any inhibitory effect against H. pylori adhesion to gastric epithelial cells. However, preincubation of the cells with 75 and 100 muM of resveratrol significantly (p<0.05 and p<0.01 respectively) inhibited the secretion of IL-8 from H. pylori-infected cells. In addition, resveratrol pretreatment at 1-100 muM suppressed H. pylori-induced ROS generation in a concentration dependent manner. Moreover, H. pylori-initiated morphological changes were markedly blocked by resveratrol. Hence, resveratrol can be considered as a potential candidate against various H. pylori related gastric pathogenic processes.

Helicobacter pylori reinfection in Brazilian patients with peptic ulcer disease: a 5-year follow-up

BACKGROUND

The Helicobacter pylori reinfection seems to be higher in developing countries, than in developed ones. The aim of the study was to determine the annual recurrence rate of H. pylori, in Brazilian patients with peptic ulcer disease, in a 5-year follow-up.

METHODS

Patients, with peptic ulcer disease diagnosed by upper digestive endoscopy (UDE) and H. pylori infection verified by histological analysis, rapid urease test, polymerase chain reaction, and urea breath test (UBT), were treated for bacterial eradication. The cure of the infection was verified using the same tests, 3 months after. Clinical evaluation and UBT were performed after sixth and ninth month. After 1 year of follow-up, UBT and UDE were repeated. Up to the fifth year, patients were assessed twice a year and an UBT was performed annually. The patients included and all the reinfected were tested for 15 different genes of the H. pylori.

RESULTS

One hundred and forty-seven patients were followed: 19 for 1 year, eight for 2 years, four for 3 years, five for 4 years, and 98 for 5 years, totaling 557 patients/years. Recurrence did not occur in the first year. In the second year, two patients were reinfected; in the third, four patients; in the fourth, three patients; and in the fifth, one patient. The total of reinfected patients was 10. The annual reinfection rate was 1.8%.

CONCLUSION

Brazil presents a low prevalence of H. pylori reinfection, similar to the developed countries.

Short-duration furazolidone therapy in combination with amoxicillin, bismuth subcitrate, and omeprazole for eradication of Helicobacter pylori

BACKGROUND/AIM

Resistance to metronidazole is one of the most common reasons for Helicobacter pylori treatment failure with the classic triple therapy. The clarithromycin-based regimen is not cost-effective for use in developing countries. Though furazolidone is a great substitute it has many side effects. Decreasing the duration of treatment with furazolidone to 1 week may help decrease the drug's side effects.

AIM

To study the efficacy and side effects of furazolidone when given for 1 week in combination with bismuth subcitrate, amoxicillin, and omeprazole.

MATERIALS AND METHODS

One hundred and seventy-seven patients with duodenal ulcer were randomly divided into two groups. Group I received omeprazole 2 Chi 20 mg + amoxicillin 2 Chi 1 g + bismuth subcitrate 4 Chi 120 mg for 2 weeks, with furazolidone 2 Chi 200 mg in the first week only. Group II received the same regimen, except that 1 week of furazolidone was followed by 1 week of metronidazole in the second week. Control endoscopy was performed after 6 weeks. Three biopsies from the antrum and three from the corpus were taken for urease testing and histology. Eradication was concluded if all tests were negative for H pylori.

RESULTS

One hundred and fifty-seven patients completed the study. Two subjects from group I and three from group II did not tolerate the regimen and were excluded from the analysis. No serious complication was detected in any patient. The eradication rates by per-protocol (PP) analysis and intention-to-treat (ITT) analysis were 89% and 79.3% in group I and 86.6% and 74.4% in group II, respectively.

CONCLUSION

One week of furazolidone in combination with 2 weeks of amoxicillin, omeprazole, and bismuth subcitrate is a safe and cost-effective regimen for the eradication of H pylori. Adding metronidazole to the above regimen does not increase the eradication rate.

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.

Furazolidone, co-amoxiclav, colloidal bismuth subcitrate, and esomeprazole for patients who failed to eradicate Helicobacter pylori with triple therapy

There is increasing evidence of Helicobacter pylori (H. pylori) resistance to the classical triple therapy consisting of a proton-pump inhibitor and clarithromycin with either amoxicillin or metronidazole. This study is aimed at establishing the efficacy and safety of a 14-day regimen to eradicate H. pylori in patients who have failed with the classical triple therapy given for 14 days. One hundred seventy-six patients diagnosed to have H. pylori infection were given triple therapy for 14 days. Fifty-two patients who failed to respond as evident from positive 14C-urea breath test (UBT) done 4-6 weeks after the completion of triple therapy were offered a combination regimen comprised of furazolidone 200 mg b.i.d, co-amoxiclav 1 g b.i.d., colloidal bismuth subcitrate 240 mg b.i.d., and esomeprazole 40 mg b.i.d. for 14 days. The mean age of these patients was 41 +/- 13 years (range 20-67). Thirty-four were males. To document eradication of H. pylori, UBT was repeated 4 weeks after the completion of treatment. On an intention-to-treat analysis, the eradication rate was 81% (42 out of 52) whereas on per-protocol basis, the eradication rate was 82.4% (42 out of 51). In conclusion, this new regimen represents a suitable second-line therapy.

Proton motive force-dependent efflux of tetracycline in clinical isolates of Helicobacter pylori

The aim of this study was to evaluate the role of proton motive force (PMF)-dependent efflux in resistance of Helicobacter pylori to tetracycline (Tet). Tet MIC was determined by agar dilution in the presence and absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), an inhibitor of PMF. Antibiotic accumulation was conducted in the presence or absence of CCCP and the fluorescence of the accumulated antibiotic was measured by spectrofluorometry. In the presence of CCCP, antibiotic accumulation was increased by 2-17-fold in 17/20 Tet(r) isolates and by 3-10-fold in four of five high-level-resistant mutants. Correlation was observed between this increase and diminution of MIC with CCCP. PMF-dependent efflux mechanisms therefore appear to play an important role in the resistance of clinical isolates of H. pylori to Tet.

Antimicrobial susceptibility and mutations involved in clarithromycin resistance in Helicobacter pylori isolates from patients in the western central region of Colombia

Resistance to metronidazole, clarithromycin, and amoxicillin (amoxicilline) was found in 82, 3.8, and 1.9% of 106 Helicobacter pylori isolates, respectively. No tetracycline-resistant isolates were found. In all of the clarithromycin-resistant isolates, only one point mutation was present, either A2143G or A2142G. Our results indicate that metronidazole should not be included in the empirical treatment of H. pylori infection in this region.

Efficacy of a 7-day course of furazolidone, levofloxacin, and lansoprazole after failed Helicobacter pylori eradication

Background

Increasing resistance to clarithromycin and nitroimidazole is the main cause of failure in the Helicobacter pylori eradication. The ideal retreatment regimen remains unclear, especially in developing countries, where the infection presents high prevalence and resistance to antibiotics. The study aimed at determining the efficacy, compliance and adverse effects of a regimen that included furazolidone, levofloxacin and lansoprazole in patients with persistent Helicobacter pylori infection, who had failed to respond to at least one prior eradication treatment regimen.

Methods

This study included 48 patients with peptic ulcer disease. Helicobacter pylori infection was confirmed by a rapid urease test and histological examination of samples obtained from the antrum and corpus during endoscopy. The eradication therapy consisted of a 7-day twice daily oral administration of lansoprazole 30 mg, furazolidone 200 mg and levofloxacin 250 mg. Therapeutic success was confirmed by a negative rapid urease test, histological examination and 14C- urea breath test, performed 12 weeks after treatment completion. The Chi-square method was used for comparisons among eradication rates, previous treatments and previous furazolidone use.

Results

Only one of the 48 patients failed to take all medications, which was due to adverse effects (vomiting). Per-protocol and intention-to-treat eradication rates were 89% (95% CI- 89%–99%) and 88% (88–92%), respectively. Mild and moderate adverse effects were reported by 41 patients (85%). For patients with one previous treatment failure, the eradication rate was 100%. Compared to furazolidone-naïve patients, eradication rates were lower in those who had failed prior furazolidone-containing regimen(s) (74% vs. 100%, p = 0.002).

Conclusion

An empiric salvage-regimen including levofloxacin, furazolidone and lansoprazole is very effective in the eradication of Helicobacter pylori, particularly in patients that have failed one prior eradication therapy.

Potent bactericidal constituents from Mallotus philippinensis against clarithromycin and metronidazole resistant strains of Japanese and Pakistani Helicobacter pylori

In the quest for potent anti-Helicobacter pylori agents, we found 70% EtOH extract of Mallotus philippinensis (LAM.) MUELL. (MPM) with strong bactericidal activity at the concentration of 15.6-31.2 mg/l against eight H. pylori strains. Further fractionation and purification of 70% EtOH extract of MPM led to the isolation of 5 compounds, namely 5,7-dihydroxy-8-methyl-6-prenylflavanone (1), 3'-prenylrubranine (2), red compound (3), isorottlerin (4), and rottlerin (5) which were elucidated on the basis of nuclear magnetic resonance and mass spectroscopy. Among the isolated compounds, rottlerin exhibited most potent bactericidal activity with minimum bactericidal concentration (MBC) value of 3.12-6.25 mg/l against several clinical H. pylori isolates including Japanese and Pakistani strains, nine clarithromycin resistant (CR), and seven metronidazole resistant (MR) strains. Minimum inhibitory concentration (MIC) values of CR (8->256 mg/l) and MR (>256 mg/l) strains were analyzed by E test. Moreover, the clarithromycin resistant strains were evaluated for A2143G and A2144G point mutations of 23s rRNA gene to correlate the MBC values with mutation type. Our results revealed the potent in vitro anti-H. pylori activity of MPM and rottlerin, specially against CR and MR strains, which could be gainfully utilized for the development of novel antimicrobials to prevent H. pylori related disorders.

Quadruple therapy with furazolidone for retreatment in patients with peptic ulcer disease

AIM: To establish the efficacy and safety of a 7-d therapeutic regimen using omeprazole, bismuth subcitrate, furazolidone and amoxicillin in patients with peptic ulcer disease who had been previously treated with other therapeutic regimens without success.

METHODS: Open cohort study which included patients with peptic ulcer who had previously been treated unsuccessfully with one or more eradication regimens. The therapeutic regimen consisted of 20 mg omeprazole, 240 mg colloidal bismuth subcitrate, 1000 mg amoxicillin, and 200 mg furazolidone, taken twice a day for 7 d. Patients were considered as eradicated when samples taken from the gastric antrum and corpus 12 wk after the end of treatment were negative for Helicobacter pylori (H pylori) (rapid urease test and histology). Safety was determined by the presence of adverse effects.

RESULTS: Fifty-one patients were enrolled. The eradication rate was 68.8% (31/45). Adverse effects were reported by 31.4% of the patients, and these were usually considered to be slight or moderate in the majority of the cases. Three patients had to withdraw from the treatment due to the presence of severe adverse effects.

CONCLUSION: The association of bismuth, furazolidone, amoxicillin and a proton-pump inhibitor is a valuable alternative for patients who failed to respond to other eradication regimens. It is an effective, cheap and safe option for salvage therapy of positive patients.

Who's Winning the War? Molecular Mechanisms of Antibiotic Resistance in Helicobacter pylori

The ability of clinicians to wage an effective war against many bacterial infections is increasingly being hampered by skyrocketing rates of antibiotic resistance. Indeed, antibiotic resistance is a significant problem for treatment of diseases caused by virtually all known infectious bacteria. The gastric pathogen Helicobacter pylori is no exception to this rule. With more than 50% of the world's population infected, H. pylori exacts a tremendous medical burden and represents an interesting paradigm for cancer development; it is the only bacterium that is currently recognized as a carcinogen. It is now firmly established that H. pylori infection is associated with diseases such as gastritis, peptic and duodenal ulceration and two forms of gastric cancer, gastric adenocarcinoma and mucosa-associated lymphoid tissue (MALT) lymphoma. With such a large percentage of the population infected, increasing rates of antibiotic resistance are particularly vexing for a treatment regime that is already fairly complicated; treatment consists of two antibiotics and a proton pump inhibitor. To date, resistance has been found to all primary and secondary lines of antibiotic treatment as well as to drugs used for rescue therapy.

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.