Comparative study of Helicobacter pylori eradication rates of twice-versus four-times-daily amoxicillin administered with proton pump inhibitor and clarithromycin: a randomized study

Background: Proton pump inhibitor (PPI)-containing triple therapy with clarithromycin and amoxicillin is now a standard regimen for Helicobacter pylori eradication in Korea. Amoxicillin has time-dependent bactericidal activity against H. pylori ; we therefore assumed a dosing schedule of amoxicillin would affect the eradication rate of H. pylori . The purpose of this study was to evaluate and compare the efficacy of different amoxicillin dosing schedules for the eradication of H. pylori .
Materials and Methods: One hundred and eighty-six patients with H. pylori infection were eligible for this study. Patients were randomly assigned to one of two regimens: amoxicillin 1000 mg with clarithromycin 500 mg and omeprazole 20 mg twice daily for 2 weeks (BID group, n = 93), or amoxicillin 500 mg four times daily with clarithromycin 500 mg and omeprazole 20 mg twice daily for 2 weeks (QID group, n = 93). The success of H. pylori eradication was evaluated 4–5 weeks after completing treatment.
Results: Overall eradication rate was 90.3%, and eradication rates were 91.4% in the BID group and 89.2% in the QID group ( p  = 0.62). Compliances was 95.7% in the BID group and 93.5% in the QID group ( p  = 0.516); this was the only factor that significantly affected H. pylori eradication in this study. Side effects in both groups were generally mild.
Conclusions: Amoxicillin regimens with PPI and clarithromycin are found to be equally effective and safe in both the BID and QID groups for H. pylori eradication. Therefore, considering patient's comfort, we recommend a twice daily amoxicillin regimen.     

Analysis of antibiotic susceptibility patterns of Helicobacter pylori isolates from Malaysia

Background: The prevalence of antibiotic resistance varies in geographic areas. The information on the antibiotic susceptibility patterns of Helicobacter pylori (H. pylori) in our local setting is therefore relevant as a guide for the treatment options. Objective: This study was conducted to determine the primary resistance rates among H. pylori isolated from Malaysian patients. Materials and methods: Biopsy samples were obtained from the stomach antrum and corpus of 777 patients from September 2004 until 2007. H. pylori isolated from these patients were then subjected to minimum inhibitory concentration (MICs) determination using E‐test method, against metronidazole, clarithromycin, levofloxacin, ciprofloxacin, amoxicillin, and tetracycline. Results: From 777 patients, 119 were positive for H. pylori where a total of 187 strains were isolated. The resistance rates were noted to be 37.4% (metronidazole), 2.1% (clarithromycin), 1% (levofloxacin and ciprofloxacin), and 0% (amoxicillin and tetracycline). Different resistance profiles were observed among isolates from the antrum and corpus of 13 patients. Resistance to one type of antibiotic was observed in 36.4% of the strains where mono‐resistance to metronidazole was the most common. Resistance to ≥2 antibiotics was noted in 3.3% of isolates. High metronidazole MICs of ≥256 μg/mL were observed among the resistant strains. Conclusions: The resistance rates of the antibiotics used in primary treatment of H. pylori infections in Malaysia are low, and multi‐antibiotic‐resistant strains are uncommon. Infections with mixed populations of metronidazole‐sensitive and ‐resistant strains were also observed. However, the high metronidazole MIC values seen among the metronidazole‐resistant strains are a cause for concern.     

Eradication of Helicobacter pylori in children in Vietnam in relation to antibiotic resistance

Background: Low Helicobacter pylori eradication rates are common in pediatric trials especially in developing countries. The aim of the study was to investigate the role of antibiotic resistance, drug dosage, and administration frequency on treatment outcome for children in Vietnam. Materials and Methods: Antibiotics resistance of H. pylori was analyzed by the Etest in 222 pretreatment isolates from children 3–15 years of age who were originally recruited in a randomized trial with two treatment regiments: lansoprazole with amoxicillin and either clarithromycin (LAC) or metronidazole (LAM) in two weight groups with once‐ or twice‐daily administration. The study design was an observational study embedded in a randomized trial. Results: The overall resistance to clarithromycin, metronidazole, and amoxicillin was 50.9%, 65.3%, and 0.5%, respectively. In LAC, eradication was linked to the strains being susceptible to clarithromycin (78.2% vs 29.3%, p = .0001). Twice‐daily dosage of proton‐pump inhibitor (PPI) and clarithromycin was more effective for eradication than once‐daily dosage for resistant strains (50.0% vs 14.7%, p = .004) and tended to be so also for sensitive strains (87.5% vs 65.2%, p = .051). Exact antibiotic dose per body weight resulted in more eradication for resistant strains (45.3% vs 8.0%, p = .006). These differences were less pronounced for the LAM regimen, with twice‐daily PPI versus once daily for resistant strains resulting in 69.2% and 50.0% eradication (p = .096), respectively. Conclusions: Helicobacter pylori clarithromycin resistance was unexpectedly high in young children in Vietnam. Clarithromycin resistance was an important cause for eradication treatment failure. Twice‐daily administration and exact antibiotic dosing resulted in more eradicated infections when the strains were antibiotic resistant, which has implications for the study design in pediatric H. pylori eradication trials.     

High Level of Antimicrobial Resistance in French Helicobacter pylori Isolates

Background:  Helicobacter pylori is a human pathogen responsible for serious diseases including peptic ulcer disease and gastric cancer. The recommended triple therapy included clarithromycin but increasing resistance has undermined its effectiveness. It is therefore important to be aware of the local prevalence of antimicrobial resistance to adjust treatment strategy.
Materials and Methods:  Overall, 530 biopsies were collected between 2004 and 2007. The antimicrobial susceptibility of H. pylori was determined by E-test and molecular methods.
Results:  Among these, 138/530 (26%) strains were resistant to clarithromycin, 324/530 (61%) to metronidazole and 70/530 (13.2%) to ciprofloxacin. Whereas no resistance against amoxicillin and tetracycline was observed, only one strain was resistant to rifampicin. Compared to the patients never treated for H. pylori infection, the prevalence of resistance was significantly higher in patients previously treated (19.1% vs 68% for clarithromycin; 13.2% vs 53.3% for both clarithromycin and metronidazole). The trend analysis revealed an increase of primary resistance to ciprofloxacin between 2004 and 2005 (7.3%) vs 2006–2007 (14.1%) ( p  = .04) and the secondary resistance reached 22.7% in 2007. Interestingly, 27 biopsies (19.6%) contained a double population of clarithromycin-susceptible and -resistant strains.
Conclusions:  The reported high prevalence of clarithromycin and multiple resistances of H. pylori suggest that the empiric therapy with clarithromycin should be abandoned as no longer pretreatment susceptibility testing has assessed the susceptibility of the strain. As culture and antibiogram are not routinely performable in most clinical laboratories, the use of molecular test should be developed to allow a wide availability of pretreatment susceptibility testing.     

Multiple mutations in or adjacent to the conserved penicillin-binding protein motifs of the penicillin-binding protein 1A confer amoxicillin resistance to Helicobacter pylori

BACKGROUND: Amoxicillin-based therapies are highly effective for the treatment of Helicobacter pylori infections, but the efficacy may decrease as the incidence of amoxicillin resistance is increasing. So far, the molecular mechanism underlying stable amoxicillin resistance has only been identified for a few naturally occurring amoxicillin-resistant (Amx) H. pylori isolates, and is mediated by mutations in penicillin-binding protein 1A (PBP1A). In this study the molecular mechanism underlying amoxicillin resistance of seven additional Amx H. pylori isolates has been established. METHODS: H. pylori strain 26695 (minimal inhibitory concentration (MIC) 0.125 mg/l) was naturally transformed with total DNA and pbp1A polymerase chain reaction (PCR) products from the seven Amx H. pylori isolates, and the MIC of amoxicillin and pbp1A gene sequence of the obtained Amx transformants were determined. RESULTS: Replacement of the wild-type pbp1A gene of H. pylori reference strain 26695 by the pbp1A gene of the Amx H. pylori isolates resulted in an increased MIC (0.5-1.0 mg/l). Sequence analysis of the smallest PBP1A fragments able to transfer the resistance indicated that several amino acid substitutions in or adjacent to the second (SKN402-404) and third (KTG555-557) conserved penicillin-binding protein motifs (PBP-motifs) mediate amoxicillin resistance in H. pylori. This was confirmed by site-directed mutagenesis using oligonucleotides that contained defined mutations in or adjacent to these PBP-motifs. CONCLUSION: In naturally occurring Amx H. pylori isolates, amoxicillin resistance is mediated by various mutational changes located in or adjacent to the second and third PBP-motifs of the PBP1A. Although we cannot exclude the role of the other genes in amoxicillin resistance, it is likely that multiple mutational changes in the PBP1A gene are the predominant cause of amoxicillin resistance in H. pylori. The findings of this study currently preclude the rapid detection of amoxicillin resistance in H. pylori by molecular tests.     

Kinetics of substrate oxidation by whole cells and cell membranes of Helicobacter pylori

Abstract Oxygen uptake by Helicobacter pylori cells and membranes was determined. Cells from stirred broth cultures or agar plates, suspended in buffer, possessed a variable and apparently endogenous respiration which could be sustained for several hours. In contrast, oxygen consumption by cells from statically incubated broth cultures, in the absence of added substrate, was transient or undetectable. These latter cells, however, oxidised ethanol, fumarate, glucose, d-lactate, pyruvate and succinate, though glucose-oxidising ability declined rapidly. The K _m s for d-lactate, pyruvate and succinate metabolism were low (≤20 μM) and oxygen uptake was approximately 1.5, 2 and 2 mol per mol substrate respectively, indicating metabolism beyond acetate plus CO₂ and implying the presence of tricarboxylic acid cycle activity. Cell membranes oxidised fumarate, d-lactate, NADH, NADPH and succinate. NADPH oxidation was six times more rapid than that of NADH. Rates of oxygen uptake by cells suspended in buffer with metabolisable substrate were < 20% of those for cells suspended in a brain heart infusion medium. Uninoculated medium consumed significant quantities of oxygen.     

幽门螺杆菌抗生素耐药机制研究进展

幽门螺杆菌(Helicobacter pylori,H.pylori)感染可引起消化性溃疡、胃粘膜相关淋巴组织淋巴瘤和胃癌。随着抗生素耐药性的问题越来越严重,耐药机制的研究也不断深入。分子检测方法,尤其是核酸检测技术,可高效、快速、准确地检测幽门螺杆菌抗生素耐药基因及突变,对幽门螺杆菌感染的临床治疗发挥重要的指导作用,同时也可对幽门螺杆菌抗生素耐药性进行大规模及时有效监控。本文讨论了关于幽门螺杆菌抗生素耐药机制并着重总结了相关耐药基因及突变。     

幽门螺杆菌相关miRNA与胃癌关系的研究进展

微小核糖核酸(microRNA,miRNA)是一种由内源基因编码长度约为22个核苷酸的非编码RNA,其能抑制靶基因蛋白质表达,有多种生物学功能。越来越多的研究表明,miRNA在多种肿瘤中异常表达,参与肿瘤发生、发展过程。幽门螺杆菌(Helicobacter pylori,Hp)作为胃癌的主要致病因素,可通过调节miRNA的表达,在胃癌中起促进或抑制作用。现就Hp相关miRNA在胃癌中的作用作一概述。     

7-day triple therapy of Helicobacter pylori infection with levofloxacin, amoxicillin, and high-dose esomeprazole in patients with known antimicrobial sensitivity

BACKGROUND AND AIMS: Failed primary anti-Helicobacter pylori therapy results in a high rate of antimicrobial resistance. This necessitates a search for new regimens to cure H. pylori infection. The aim of this study was to evaluate the efficacy and tolerability of a new levofloxacin-containing 7-day triple therapy and to compare it with that of standard French triple therapy in patients with known H. pylori susceptibility to MET (metronidazole) and CLA (clarithromycin). PATIENTS AND METHODS: Sixty-one patients with documented antibiotic sensitivity (E-test) and an indication for anti-H. pylori treatment based on the Maastricht Consensus 2/2000 guidelines were randomized to receive either esomeprazole 2 x 40 mg, levofloxacin 2 x 500 mg, and amoxicillin 2 x 1 g for 7 days (ELA, n = 30), or esomeprazole 2 x 20 mg, clarithromycin 2 x 500 mg, and amoxicillin 2 x 1 g for 7 days (ECA, n = 31). A cure check was performed 4-6 weeks after conclusion of therapy. RESULTS: Sixty-one patients were randomized to the two treatment groups. Twenty-eight of 30 patients of the ELA group were available for per-protocol (PP) analysis, of whom 26 (92.9% CI: 76-99%; intention-to-treat [ITT] analysis 86.7% CI: 68-96%) became H. pylori negative compared with 26 of the 31 patients of the ECA group (83.9%, CI: 66-93% both PP and ITT analyses). Five patients of the ELA group showed CLA resistance, three of whom also showed MET resistance, and all five were treated successfully. Two patients with levofloxacin-resistant strains, one in each group, were cured. Both regimens were generally well tolerated with minor adverse events being seen in 15 patients (51.7%) of the ELA group and in 13 (40.6%) of the ECA group. None of the patients discontinued treatment prematurely due to adverse events. CONCLUSION: The data of this pilot study suggest a better than 80% efficacy of the new 7-day levofloxacin triple therapy, which is within the range of the French triple therapy in patients with MET- and CLA-susceptible strains. The data suggest that the new levofloxacin triple therapy may also be an option in patients with MET- and CLA-resistant H. pylori strains.     

The effects of nocturnal acid breakthrough on Helicobacter pylori eradication

Background. The effects of nocturnal gastric acid breakthrough (NAB) on Helicobacter pylori eradication are still unknown in peptic ulcer patients. The purposes of this study were to compare the effect of lansoprazole 30 mg twice a day (bid) to lansoprazole 60 mg once a day (qd) on the prevalence of NAB, and to determine whether NAB affects the eradication of H. pylori in peptic ulcer patients. Methods. Experiments were carried out in 67 patients with H. pylori‐positive peptic ulcers. They were randomized into two groups, one treated with a combination of lansoprazole 60 mg, clarithromycin 1.0 g, and amoxycillin 2.0 g once a day before breakfast (qd group), and the other, divided doses of the drugs were given before breakfast and dinner (bid group) for 2 weeks. Results. NAB occurred in 31 patients, 55.2% in qd group, and 39.5% in bid group (p = .226). H. pylori eradication was achieved in 61.3% in NAB positive group and 83.3% in NAB negative group (p = .055). The mean duration of NAB for H. pylori eradication group was 99.3 ± 22.7 min, and 293.2 ± 49.8 min for H. pylori persistence group (p < .05). The median intragastric pH of the H. pylori eradication and persistence group was 5.7 ± 0.2 and 4.2 ± 0.4, respectively (p < .05). Conclusions. Neither the morning dose and the divided dose regimen of lansoprazole affected the intragastric acidity and occurrence of the NAB. NAB did not influence H. pylori eradication in peptic ulcer patients, but the duration of NAB and total intragastric median pH were found to influence the H. pylori eradication.     

Interleukin-2 gene polymorphisms associated with increased risk of gastric atrophy from Helicobacter pylori infection

BACKGROUND: Gastric atrophy induced by Helicobacter pylori is thought to predispose patients to noncardiac gastric cancer development. However, the host genetic factors that influence the progression of gastric atrophy have not been elucidated. In this study, we examined the effects of cytokine polymorphisms on H. pylori-induced gastric atrophy. METHODS: Blood samples were taken from 454 Japanese subjects. The interleukin-2 (IL-2; T-330G), IL-4 (C-33T), and IL-13 (C-1111T) polymorphisms were genotyped by polymerase chain reaction with confronting two-pair primers (PCR-CTPP). Anti-H. pylori IgG antibody and pepsinogen I and II were measured to diagnose H. pylori infection and atrophic gastritis. RESULTS: The odds ratios (ORs) for the association between IL-2 polymorphism [OR = 2.78, 95% CI (confidence interval) = 1.26-6.17 (T/T to G/G)] or IL-4 polymorphism [OR = 2.22, 95% CI = 1.01-4.89 (T/C to C/C)] were increased significantly with gastric atrophy, whereas the corresponding OR of IL-13 polymorphism was decreased with gastric atrophy [OR = 0.61, 95% CI = 0.39-0.96 (C/T and T/T to C/C)]. There were no significant H. pylori seropositivity-related differences between these polymorphisms. We examined the relationship between these polymorphisms and gastric atrophy separately in H. pylori-seropositive and -seronegative groups. In the H. pylori-seropositive group, the IL-2 T/T (OR = 2.78, 95% CI = 1.12-6.93) had a significant association with gastric atrophy. CONCLUSIONS: These results reveal that the IL-2 gene polymorphism is associated with an increased risk of gastric atrophy induced by H. pylori infection and might predispose to gastric cancer.     

Molecular diagnosis of Helicobacter pylori antibiotic resistance in the Taif region,Saudi Arabia

Success in eradication of Helicobacter pylori is declining globally because H. pylori has developed resistance against most of the antibiotics proposed for eradication regimens, mainly through point mutations. The present study included 200 patients with dyspepsia attending Taif Hospital. Gastric biopsies were obtained during gastroscopy and subjected to rapid urease testing. Molecular methods were used to confirm diagnoses of H. pylori infection and to identify resistance gene variants of four antibiotics; namely, clarithromycin, metronidazole, fluoroquinolones and tetracycline (23S rRNA, gyrA, rdxA and 16S rRNA respectively). Of all investigated patients, Molecular diagnoses were made in 143 of all investigated patients; thus, the prevalence was .5%. The overall rate of resistance to clarithromycin among the H. pylori‐positive patients was high (39.9%) and the rate of resistance significantly greater (48.2%) among the secondary resistance group, secondary resistance being defined as resistance as a result of previous exposure to the relevant antibiotic. The rate of resistance to fluoroquinolones was considered moderate; the difference in rate of resistance between the primary and secondary resistance groups (8.4% and 9.5%, respectively) was not significant Also, there was a low prevalence of both primary and the secondary tetracycline resistance in the study cohort. In contrast, the prevalence of metronidazole resistance was considered high with no significant difference between the two resistance groups. H. pylori showed an increased prevalence of resistance to all four of the commonly used therapeutic agents. Thus, eradication therapy should be based on the regional results of susceptibility testing. Moreover, treatment tailored according to individually determined H. pylori susceptibility may be a reasonable future goal.     

Modified sequential Helicobacter pylori therapy: proton pump inhibitor and amoxicillin for 14 days with clarithromycin and metronidazole added as a quadruple (hybrid) therapy for the final 7 days

Background: Ten‐day sequential therapy with a proton pump inhibitor (PPI) and amoxicillin followed by a PPI, clarithromycin, and an imidazole typically achieves Helicobacter pylori eradication rates of 90–94% (Grade B success). Aims: We tested whether prolonging treatment and continuing amoxicillin throughout the 14‐day treatment period would produce a ≥95% result. Methods: This was a multicenter pilot study in which H. pylori‐infected patients received a 14‐day sequential–concomitant hybrid therapy (esomeprazole and amoxicillin for 7 days followed by esomeprazole, amoxicillin clarithromycin, and metronidazole for 7 days). H. pylori status was examined 8 weeks after therapy. Success was defined as achieving ≥95% eradication by per‐protocol analysis. Results: One hundred and seventeen subjects received hybrid therapy. The eradication rate was 99.1% (95% confidence interval (CI), 97.3–100.0%) by per‐protocol analysis and 97.4% by intention‐to‐treat analysis (95% CI, 94.5–100.0%). Adverse events were seen in 14.5%; drug compliance was 94.9%. Conclusions: Fourteen‐day hybrid sequential–concomitant therapy achieved >95%H. pylori eradication (Grade A result). Further studies are needed 1, in regions with different patterns and frequencies of resistance to confirm these findings, and 2, to examine whether Grade A success is maintained with hybrid therapy shorter than 14 days.     

幽门螺杆菌随机扩增多态性DNA指纹图谱分析

应用随机扩增多态性DNA指纹法(RandomamplifiedpolymorphicDNA,RAPD)对来自29例消化性溃疡和19例单纯性胃炎病人的幽门螺杆菌(Helicobacterpylori,Hp)菌株基因组DNA进行PCR反应,建立Hp的DNA指纹图谱,运用统计分析软件(Statisticanalysissoftware,SAS)对HpDNA指纹图的相似性以及与疾病的相关性进行分析。结果显示,这些菌株按HpDNA指纹图可分为两大类,两种来源的菌株在两大类中的比例有明显差异(P<0.05)。提示可能存在与疾病相关的特异基因型。     

和厚朴酚对幽门螺杆菌生长和空泡毒素A表达及活性的影响

【目的】幽门螺杆菌(Helicobacter pylori, H. pylori)是胃炎和消化性溃疡的病原体, 但其具有潜在的正常菌群的特性。本研究通过评价临床常用中药厚朴的活性成分和厚朴酚对H. pylori的抑制作用及对其空泡毒素A表达和活性的影响, 以反映其对H. pylori具有的潜在去除毒性的作用。【方法】使用平皿稀释固体法和脑心浸液液体法测定和厚朴酚对H. pylori的最低抑菌浓度, 进一步通过中性红摄入法评价经无抑菌效果的低浓度和厚朴酚干预后, H. pylori培养上清中空泡毒素A (Vacuolating cytotoxin A, VacA)的毒性作用; 并通过RT-PCR和Western blot方法检测经低浓度和厚朴酚处理后, H. pylori菌体及分泌上清中VacA mRNA和蛋白的表达水平。【结果】发现高浓度(0.75 g/L)和厚朴酚对H. pylori 具有抑制作用; 而在远低于最低抑菌浓度时, 和厚朴酚可有效抑制H. pylori VacA的形成和分泌。【结论】和厚朴酚具有下调H. pylori毒性的潜在作用, 这为基于“致病性H. pylori的非致病性转变”这一机理的干预性治疗提供了有希望的研究前景。     

幽门螺杆菌感染诊断方法的比较

目的:考核各种H.pylori感染诊断方法,试图证明分离培养仍是细菌性感染诊断的最可靠方法.方法:315例胃十二指肠疾病患者同时进行胃活检组织分离培养,病理切片找菌,快速脲酶试验,14CO2呼气试验检查,比较它们之间的检出率差异.结果:四种方法各自的总检出率差异无显著性.以分离培养为金标准,其他方法的误诊误治率可达12.06%～22.22%.各种诊断方法对H.pylori感染的实际检出率差异存在着显著性.结论:本研究提示,分离培养应为H.pylori感染临床诊断的金标准.     

Antibacterial effects of the urushiol component in the sap of the lacquer tree (Rhus verniciflua Stokes) on Helicobacter pylori

Background: Urushiol is a major component of the lacquer tree which has been used as a folk remedy for the relief of abdominal discomfort in Korea. The aim of this study was to evaluate the antibacterial effects of the urushiol on Helicobacter pylori. Materials and Methods: Monomer and 2–4 polymer urushiol were used. In the in vitro study, pH‐ and concentration‐dependent antibacterial activity of the urushiol against H. pylori were investigated. In addition, the serial morphological effects of urushiol on H. pylori were examined by electron microscopy. In vivo animal study was performed for the safety, eradication rate, and the effect on gastritis of urushiol. The expression of pro‐inflammatory cytokines was checked. Results: All strains survived within a pH 6.0–9.0. The minimal inhibitory concentrations of the extract against strains ranged 0.064–0.256 mg/mL. Urushiol caused separation of the membrane and lysis of H. pylori within 10 minutes. Urushiol (0.128 mg/mL × 7 days) did not cause complications on mice. The eradication rates were 33% in the urushiol monotherapy, 75% in the triple therapy (omeprazole + clarithromycin + metronidazole), and 100% in the urushiol + triple therapy, respectively. H. pylori‐induced gastritis was not changed by urushiol but reduced by eradication. Only the expression of interleukin‐1β in the gastric tissue was significantly increased by H. pylori infection and reduced by the urushiol and H. pylori eradication (p = .014). Conclusions: The urushiol has an antibacterial effect against H. pylori infection and can be used safely for H. pylori eradication in a mouse model.