Helicobacter pylori: the challenge in therapy

Advances in Helicobacter pylori vaccine research: From candidate antigens to adjuvants-A review

BACKGROUND

Helicobacter pylori is a Gram-negative, spiral-shaped bacterium that infects approximately 50% of the world's population and has been strongly associated with chronic gastritis, peptic ulcers, gastric mucosa-associated lymphoma, and gastric cancer. The elimination of H. pylori is currently considered one of the most effective strategies for the treatment of gastric-related diseases, so antibiotic therapy is the most commonly used regimen for the treatment of H. pylori infection. Although this therapy has some positive effects, antibiotic resistance has become another clinically prominent problem. Therefore, the development of a safe and efficient vaccine has become an important measure to prevent H. pylori infection.

METHODS

PubMed and ClinicalTrials.gov were systematically searched from January 1980 to March 2023 with search terms-H. pylori vaccine, adjuvants, immunization, pathogenesis, and H. pylori eradication in the title and/or abstract of literature. A total of 5182 documents were obtained. Based on the principles of academic reliability, authority, nearly publicated, and excluded the similar documents, finally, 75 documents were selected, organized, and analyzed.

RESULTS

Most of the candidate antigens used as H. pylori vaccines in these literatures are whole-cell antigens and virulence antigens such as UreB, VacA, CagA, and HspA, and the main types of vaccines for H. pylori are whole bacteria vaccines, vector vaccines, subunit vaccines, nucleic acid vaccines, epitope vaccines, etc. Some vaccines have shown good immune protection in animal trials; however, few vaccines show good in clinical trials. The only H. pylori vaccine passed phase 3 clinical trial is a recombinant subunit vaccine using Urease subunit B (UreB) as the vaccine antigen, and it shows good prophylactic effects. Meanwhile, the adjuvant system for vaccines against this bacterium has been developed considerably. In addition to the traditional mucosal adjuvants such as cholera toxin (CT) and E. coli heat labile enterotoxin (LT), there are also promising safer and more effective mucosal adjuvants. All these advances made safe and effective H. pylori vaccines come into service as early as possible.

CONCLUSIONS

This review briefly summarized the advances of H. pylori vaccines from two aspects, candidates of antigens and adjuvants, to provide references for the development of vaccine against this bacterium. We also present our prospects of exosomal vaccines in H. pylori vaccine research, in the hope of inspiring future researchers.

Helicobacter pylori infection in pregnant women: Gastrointestinal symptoms and pregnancy- related disorders

Helicobacter pylori (H. Pylori) is a gram-negative, flagellated and spiral-shaped bacterial pathogen that impacts approximately 46% among pregnant women globally and has been associated with various maternal-fetal complications. Iron deficiency anemia, fetal growth restriction, cardiovascular diseases, and insufficient nutrient absorption can be observed in pregnant women, as well as miscarriages and pregnancy-specific hypertensive disease, such as pre-eclampsia. Thus, the evidence supports the influence of H. pylori infection on fetal implantation/placentation failure, and positive strains of the cytotoxin-associated gene A of H. Pylori were reported as the most prevalent in these conditions. However, current knowledge indicates a relationship between this infection and the occurrence of hyperemesis gravidarum, characterized by frequent nausea and vomiting. Regarding the diagnosis of this bacterial infection, non-invasive approaches such as stool antigen test, urea breath test, and serological tests are more accepted during pregnancy, as they are easy to carry out and cost-effective. Finally, the bacteria eradication therapy should consider the risks and benefits for the pregnant woman and her child, with pharmacological intervention depending on the clinical presentation.

Progress in genetic engineering of peanut (Arachis hypogaea L.)--a review

Peanut (Arachis hypogaea L.) is a major species of the family, Leguminosae, and economically important not only for vegetable oil but as a source of proteins, minerals and vitamins. It is widely grown in the semi-arid tropics and plays a role in the world agricultural economy. Peanut production and productivity is constrained by several biotic (insect pests and diseases) and abiotic (drought, salinity, water logging and temperature aberrations) stresses, as a result of which crop experiences serious economic losses. Genetic engineering techniques such as Agrobacterium tumefaciens and DNA-bombardment-mediated transformation are used as powerful tools to complement conventional breeding and expedite peanut improvement by the introduction of agronomically useful traits in high-yield background. Resistance to several fungal, virus and insect pest have been achieved through variety of approaches ranging from gene coding for cell wall component, pathogenesis-related proteins, oxalate oxidase, bacterial chloroperoxidase, coat proteins, RNA interference, crystal proteins etc. To develop transgenic plants withstanding major abiotic stresses, genes coding transcription factors for drought and salinity, cytokinin biosynthesis, nucleic acid processing, ion antiporter and human antiapoptotic have been used. Moreover, peanut has also been used in vaccine production for the control of several animal diseases. In addition to above, this study also presents a comprehensive account on the influence of some important factors on peanut genetic engineering. Future research thrusts not only suggest the use of different approaches for higher expression of transgene(s) but also provide a way forward for the improvement of crops.

Nontraditional therapies to treat Helicobacter pylori infection

The Gram-negative pathogen Helicobacter pylori is increasingly more resistant to the three major antibiotics (metronidazole, clarithromycin and amoxicillin) that are most commonly used to treat infection. As a result, there is an increased rate of treatment failure; this translates into an overall higher cost of treatment due to the need for increased length of treatment and/or the requirement for combination or sequential therapy. Given the rise in antibiotic resistance, the complicated treatment regime, and issues related to patient compliance that stem from the duration and complexity of treatment, there is clearly a pressing need for the development of novel therapeutic strategies to combat H. pylori infection. As such, researchers are actively investigating the utility of antimicrobial peptides, small molecule inhibitors and naturopathic therapies. Herein we review and discuss each of these novel approaches as a means to target this important gastric pathogen.

Antibiotics resistance of Helicobacter pylori and treatment modalities in children with H. pylori infection

Pediatric infection with Helicobacter pylori may occur early in childhood and persist lifelong. Global pediatric clinical studies have reported a decreasing tendency in the overall rate of H. pylori eradication. In pediatric patients with H. pylori infection, pediatric patients with peptic ulcer, and the first-degree relatives of patients with a history of gastric cancer, it is commonly recommended that H. pylori strains be eradicated. Antibiotic drug resistance to H. pylori, which has been reported to vary widely between geographic regions, is mainly associated with treatment failure in these patients. It is therefore imperative that the antibiotic resistance rates of H. pylori in children and adolescents be meticulously monitored across countries and throughout geographic regions. This paper particularly focuses on the antibiotic drug resistance of H. pylori and the thearpy of pediatric H. pylori infection cases.

Immunogenicity of oral vaccination with Lactococcus lactis derived vaccine candidate antigen (UreB) of Helicobacter pylori fused with the human interleukin 2 as adjuvant

Helicobacter pylori (H. pylori) infection remains a significant global public health problem. Vaccine, especially edible vaccine, is considered to be effective in the management of H. pylori infections. By using recombinant technology, Lactococcus lactis (L. lactis) could serve as an antigen-delivering vehicle for the development of edible vaccine. The aim of this study was to produce edible UreB (urease B) vaccine derived from L. lactis against H. pylori. The UreB subunit is the most effective and common immunogen of all strains of H. pylori. The UreB was produced as a chimeric protein fused with IL-2 (human interleukin 2) as the mucosal adjuvant. Mucosal immunization of mice with recombinant L. lactis NZ9000 containing the UreB-IL-2 protein elicited more anti-UreB antibody that specifically bounded to the purified bacterial UreB protein and more cytokines such as IFN-γ, IL-4, and IL-17, and had a lower H. pylori burden and urease activity than control mice. These results suggest that the recombinant L. lactis expressing UreB-IL-2 can be potentially used as an edible vaccine for controlling H. pylori infection.

Genipin-cross-linked fucose-chitosan/heparin nanoparticles for the eradication of Helicobacter pylori

Helicobacter pylori is a significant human pathogen that recognizes specific carbohydrate receptors, such as the fucose receptor, and produces the vacuolating cytotoxin, which induces inflammatory responses and modulates the cell-cell junction integrity of the gastric epithelium. The clinical applicability of topical antimicrobial agents was needed to complete the eradication of H. pylori in the infected fundal area. In the present study, we combined fucose-conjugated chitosan and genipin-cross-linking technologies in preparing multifunctional genipin-cross-linked fucose-chitosan/heparin nanoparticles to encapsulate amoxicillin of targeting and directly make contact with the region of microorganism on the gastric epithelium. The results show that the nanoparticles effectively reduced drug release at gastric acids and then released amoxicillin in an H. pylori survival situation to inhibit H. pylori growth and reduce disruption of the cell-cell junction protein in areas of H. pylori infection. Furthermore, with amoxicillin-loaded nanoparticles, a more complete H. pylori clearance effect was observed, and H. pylori-associated gastric inflammation in an infected animal model was effectively reduced.

Cholesterol enhances Helicobacter pylori resistance to antibiotics and LL-37

The human gastric pathogen Helicobacter pylori steals host cholesterol, modifies it by glycosylation, and incorporates the glycosylated cholesterol onto its surface via a cholesterol glucosyltransferase, encoded by cgt. The impact of cholesterol on H. pylori antimicrobial resistance is unknown. H. pylori strain 26695 was cultured in Ham's F12 chemically defined medium in the presence or absence of cholesterol. The two cultures were subjected to overnight incubations with serial 2-fold dilutions of 12 antibiotics, six antifungals, and seven antimicrobial peptides (including LL-37 cathelicidin and human alpha and beta defensins). Of 25 agents tested, cholesterol-grown H. pylori cells were substantially more resistant (over 100-fold) to nine agents than were H. pylori cells grown without cholesterol. These nine agents included eight antibiotics and LL-37. H. pylori was susceptible to the antifungal drug pimaricin regardless of cholesterol presence in the culture medium. A cgt mutant retained cholesterol-dependent resistance to most antimicrobials but displayed increased susceptibility to colistin, suggesting an involvement of lipid A. Mutation of lpxE, encoding lipid A1-phosphatase, led to loss of cholesterol-dependent resistance to polymyxin B and colistin but not other antimicrobials tested. The cgt mutant was severely attenuated in gerbils, indicating that glycosylation is essential in vivo. These findings suggest that cholesterol plays a vital role in virulence and contributes to the intrinsic antibiotic resistance of H. pylori.

Dual proton pump inhibitor plus amoxicillin as an empiric anti-H. pylori therapy: studies from the United States

BACKGROUND

Studies with CYP2C19 slow metabolizers have shown that the combination of a proton pump inhibitor (PPI) plus amoxicillin (dual therapy) can reliably cure more than 90% of Helicobacter pylori infections. Theoretically, the use of a PPI dose that provides equivalent acid suppression with fast metabolizers and slow metabolizers would achieve high cure rates irrespective of the CYP2C19 genotype.

AIM

To evaluate high-dose PPI plus amoxicillin dual therapy for H. pylori eradication.

METHODS

H. pylori-infected individuals (positive by 2 tests) received esomeprazole 40 mg plus amoxicillin 750 mg every 8 h for 14 days. The protocol was planned based on the "efficient identification strategy" requiring more than 90% success, with stop criteria of 6 or more failures within 50 patients or a cure rate of less than 80%.

RESULTS

Thirty-six patients (5 women, 31 men), average age 58 years, were enrolled before achieving stop criteria. All were first H. pylori treatments. The intention-to-treat cure was achieved in 26/36 [72.2%; 95% confidence interval (CI) = 56-84%] and in 26/35 per protocol (74.2%; 95% CI = 56-87%). There were no significant side effects. Compliance was 85% or greater in all (100% in 91.6%).

CONCLUSIONS

If the hypothesis that consistently high intragastric pH is required to reliably achieve more than 90% H. pylori eradication, our regimen was not sufficient. Success may require more than every 8 h dosing, the concomitant administration of sodium bicarbonate, or the use of a long-acting PPI. However, the result was positive in that dual therapy with the doses tested here was at least as successful as empiric triple therapy.

Clinical practice: diagnosis and evaluation of dyspepsia

The main issue regarding the approach to the patient with uninvestigated dyspepsia is whether the symptoms are the result of an important clinical illness, which then determines the appropriate management strategy for the treatment of the symptoms. An initial trial of empiric antisecretory drugs is recommended for those without Helicobacter pylori infection and no alarm symptoms, whereas H. pylori eradication is recommended for those with an active H. pylori infection. Treatment expectations for H. pylori infections should theoretically be similar to other common infectious diseases. In most regions, clarithromycin resistance has undermined traditional triple therapy so that it is no longer a suitable choice as an empiric therapy. Four drug therapies, such as sequential, concomitant, and bismuth-quadruple therapy are generally still acceptable choices as empiric therapies. Posteradication testing is highly recommended to provide early identification of otherwise unrecognized increasing antimicrobial resistance. However, despite the ability to successfully cure H. pylori infections, a symptomatic response can be expected in only a minority of those with dyspepsia not associated with ulcers (so called nonulcer dyspepsia). Overall, from the patients stand point, symptomatic relief is often difficult to achieve and physicians must rely on reassurance along with empiric and individualized care.

Anti-inflammatory actions of probiotics through activating suppressor of cytokine signaling (SOCS) expression and signaling in Helicobacter pylori infection: a novel mechanism

BACKGROUND AND AIMS

In spite of the International Agency for Research on Cancer's definition that Helicobacter pylori is the definite carcinogen of gastric cancer, the simple eradication of the bug is not enough to prevent resultant gastric cancer, and increasing microbial resistance further limits the eradication application. Therefore, probiotics, non-pathogenic microbial feed that can affect the host in a beneficial manner, could be an alternate way to enhance anti-inflammation against H. pylori. However, the mechanism of their anti-inflammatory actions is still unclear. In the current study, we hypothesized that suppressor of cytokine signaling (SOCS) signaling could be a feasible anti-inflammatory mechanism of probiotics against H. pylori infection.

RESULTS

H. pylori infection or their lipopolysaccharide stimulation led to significant increased expressions of inflammatory mediators including tumor necrosis factor-alpha, interleukin-8, inducible nitric oxide synthase and cyclooxygenase-2 in AGS cells and pretreatment of Lactobacillus plantarum, Lactobacillus rhamnosis and Lactobacillus acidophilus significantly attenuated the expressions of these inflammatory mediators in accordance with the blocking action of nuclear factor-kappaB nuclear translocation. Probiotic administration increased expression of SOCS-2 and SOCS-3 and exerted the active SOCS signaling featured with earlier and higher expressions of SOCS-2 and SOCS-3. In contrast to weak inactivation of mitogen-activated protein kinases including p-38 and extracellular signal-regulated kinase 1/2, probiotic-induced SOCS expressions were mediated through either significant phosphorylation of signal transducers and activation of transcription (STAT)-1 and STAT-3 or simultaneous inhibition of Janus kinase (JAK)2 phosphorylation, which is known to signal SOCS-2/SOCS-3 negatively.

CONCLUSION

Anti-inflammatory signals of SOCS through STAT-1/STAT-3 activation and JAK2 inactivation might be a key anti-inflammatory mechanism of probiotics, setting probiotics as a non-microbial strategy to H. pylori infection.

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

BACKGROUND & AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Short-term celecoxib intervention is a safe and effective chemopreventive for gastric carcinogenesis based on a Mongolian gerbil model

AIM

To evaluate the optimal intervention point of a selective cyclooxygenase-2 (COX-2) inhibitor, celecoxib, for inhibiting Helicobacter pylori (H. pylori)-associated gastric carcinogenesis in Mongolian gerbils (MGs).

METHODS

One hundred and twelve MGs were divided into six groups (A-F). One hundred gerbils were inoculated with H. pylori (groups A-E). Twelve gerbils were inoculated with vehicle broth only (group F). After 4 wk, they were given N'-methyl-N'-nitro-N-nitroso-guanidine (MNNG) (50 microg/mL) in the drinking water for 20 wk. In groups B-E, the animals were given the stock celecoxib (10 mg/kg per day) diet from the 21st, 31st, 21st and 41st week respectively. The periods of administering celecoxib were 30, 20, 20, and 15 wk respectively. On the 51st week, the animals were sacrificed for histological examination. Local PCNA expression was examined by the immunohistochemistry method. The expression of COX-2 protein was assessed by western blot. Analysis used the chi(2) test. The difference was regarded as significant when P value was less than 0.05.

RESULTS

Seventeen percent (17/100) of H. pylori-infected MGs developed gastric cancer. All of these lesions were well-differentiated adenocarcinoma. The incidence rates of adenocarcinoma in groups A-F were 40%, 0%, 0%, 20%, 25%, and 0% respectively. The inflammatory scores were higher in group B than in other groups. There was no inflammatory response noted in group F. Celecoxib treatment resulted in a significant reduction in the proliferation of H. pylori-infected mucosal cells (groups B, C and D) (P < 0.01). The expression of COX-2 protein was significantly attenuated in the groups which were celecoxib-treated for more than 20 wk (groups B, C, D). The groups treated with celecoxib had a significantly lower rate of advanced gastric cancer (34% vs 75%, P < 0.001) There were no sudden deaths in any of the groups.

CONCLUSION

Short-term treatment with celecoxib has an anti-carcinogenic effect, and resulted in less severe inflammation and inhibited the invasive degree of gastric cancer.

Amoxicillin, clarithromycin, and omeprazole based targeted nanoparticles for the treatment of H. pylori

The aim of the present study was to develop and characterize targeted sustained release nanoparticles of chitosan-glutamic acid conjugates containing triple therapy for Helicobacter pylori to improve its therapeutic effect and reduce its dose-related side effect. The chitosan-glutamate nanoparticles were prepared by using the ionotropic gelation method. The particle sizes of systems ranged between 550 nm and 900 nm. Percent drug entrapment and release profiles of amoxicillin, clarithromycin, and omeprazole in simulated gastric fluid (pH 1.2) were determined using high-performance liquid chromatography. The maximum % drug entrapment and % yield of formulations were about 60-90% and 73-88%, respectively. The stability of the drugs was assessed in simulated gastric fluid (pH 1.2). In vitro antibacterial efficacy of optimized formulations containing monotherapy and triple therapy on isolated culture of H. pylori was assessed. In vivo clearance study and histopathological study were also carried out on Swiss albino mice to evaluate the efficacy of triple therapy containing targeted nanosystem for the treatment of H. pylori. The proposed delivery system holds promise at optimizing the treatment of H. pylori.

Oral vaccination of mice against Helicobacter pylori with recombinant Lactococcus lactis expressing urease subunit B

To determine whether a protective immune response could be elicited by oral delivery of a recombinant live bacterial vaccine, Helicobacter pylori urease subunit B (UreB) was expressed for extracellular expression in food-grade bacterium Lactococcus lactis. The UreB-producing strains were then administered orally to mice, and the immune response to UreB was examined. Orally vaccinated mice produced a significant UreB-specific serum immunoglobulin G (IgG) response. Specific anti-UreB IgA responses could be detected in the feces of mice immunized with the secreting lactococcal strain. Mice vaccinated orally were significantly protected against gastric Helicobacter infection following a challenge with H. pylori strain SS1. In conclusion, mucosal vaccination with L. lactis expressing UreB produced serum IgG and UreB-specific fecal IgA, and prevented gastric infection with H. pylori.

Oral vaccination of mice against Helicobacter pylori with recombinant Lactococcus lactis expressing urease subunit B

To determine whether a protective immune response could be elicited by oral delivery of a recombinant live bacterial vaccine, Helicobacter pylori urease subunit B (UreB) was expressed for extracellular expression in food-grade bacterium Lactococcus lactis. The UreB-producing strains were then administered orally to mice, and the immune response to UreB was examined. Orally vaccinated mice produced a significant UreB-specific serum immunoglobulin G (IgG) response. Specific anti-UreB IgA responses could be detected in the feces of mice immunized with the secreting lactococcal strain. Mice vaccinated orally were significantly protected against gastric Helicobacter infection following a challenge with H. pylori strain SS1. In conclusion, mucosal vaccination with L. lactis expressing UreB produced serum IgG and UreB-specific fecal IgA, and prevented gastric infection with H. pylori.

Hyperemesis gravidarum and Helicobacter pylori infection: a systematic review

OBJECTIVE

To systematically review studies examining the relationship between hyperemesis gravidarum and Helicobacter pylori (H pylori) infection.

DATA SOURCES

A 1966 to January 2007 search using MEDLINE/PubMed, EMBASE, and Web of Science included MeSH terms: "Helicobacter pylori," "Helicobacter infections," "hyperemesis gravidarum," and the text words "nausea," "vomit," "pregnancy," and "Helicobacter." References of selected papers were examined for additional relevant studies.

METHODS OF STUDY SELECTION

We evaluated studies investigating a relationship between hyperemesis gravidarum and H pylori infection. Studies were included in which the diagnosis of hyperemesis gravidarum was made at or before entry into the study, and H pylori diagnosis was made by serum antibody sample, gastric biopsy, saliva test, or stool sample. The search produced 169 titles; 22 were reviewed in further detail.

TABULATION, INTEGRATION, AND RESULTS

Fourteen case-control studies met established criteria, involving 1,732 participants and controls tested for H pylori infection. Studies were evaluated according to patient demographics and study methodology (case definition, exclusion criteria, H pylori testing). An estimate of the odds ratios with 95% confidence intervals was calculated by using a random effects model for dichotomous variables with review article software. Ten studies showed a significant association between hyperemesis gravidarum and H pylori infection. Odds ratios varied from 0.55 to 109.33; three results were less than 1.0. Tests for heterogeneity applied to several subgroups were considerable with values above 75% for all groups.

CONCLUSION

An association between hyperemesis gravidarum and H pylori infection is suggested by this systematic review. However, the considerable heterogeneity among studies highlights study limitations.

Levofloxacin-containing triple therapy to eradicate the persistent H. pylori after a failed conventional triple therapy

OBJECTIVE

To identify the optimal dosage of levofloxacin to eradicate persistent Helicobacter pylori when triple therapy with amoxicillin, clarithromycin, and omeprazole fails.

METHODS

We investigated 124 patients whose triple therapy including clarithromycin had failed. Clarithromycin resistance was indirectly assessed by the (13)C-urea breath test, with a post-treatment value cut-off point at 15. All patients were randomly divided into two groups, to receive 1-week amoxicillin 1 g and lansoprazole 30 mg twice daily, plus either levofloxacin 500 mg once (ALL-500 group) or twice daily (ALL-1000 group). Six weeks later, the (13)C-urea breath test was repeated to assess whether H. pylori was eradicated.

RESULTS

Intention-to-treat (ITT) and per-protocol (PP) analysis showed no difference in H. pylori eradication rates in both the ALL-500 and ALL-1000 groups (ITT: 79% vs. 80.6%, p > .05; PP: 86% vs. 87.5%, p > .05). For both groups, the per-protocol H. pylori eradication rates were also similarly high between patients with a post-treatment value of (13)C-urea breath test < or = 15 and those with a value > 15 (ALL-500: 85% vs. 86.5%, p > .05; ALL-1000: 88.9% vs. 86.8%, p > .05).

CONCLUSION

One-week levofloxacin 500 mg daily-based triple therapy is effective for eradicating the persistent H. pylori after a failed triple therapy with amoxicillin, clarithromycin, and omeprazole.

Optimal length of triple therapy for H pylori eradication in a population with high prevalence of infection in Chile

AIM: To compare the efficacy of 7-d versus 14-d triple therapy for the treatment of H pylori infection in Chile, with a prevalence of 73% in general population.

METHODS: H pylori-infected patients diagnosed by rapid urease test, with non-ulcer dyspepsia or peptic ulcer disease were randomized to receive omeprazole 20 mg bid, amoxicillin 1 g bid, and clarithromycin 500 mg bid for 7 (OAC7) or 14 (OAC14) d. Primary outcome was eradication rate 6 wk after the treatment. Subgroup analysis was carried out considering the eradication rate among patients with or without peptic ulcer disease and eradication rate among smokers or non-smokers.

RESULTS: One hundred and thirty-one patients were randomized to OAC7 (n = 69) or OAC14 (n = 62). The overall eradication rate (intention-to-treat) was 78.3% in OAC7 and 85.5% in OAC14 groups, without a significant difference (P =0.37). No significant difference in the eradication rate was found among the patients with peptic ulcer disease (n = 31) between the OAC7 group (85.7%) and OAC14 group (87.5%). However, smokers had an obviously lower eradication rate compared to non-smokers, particularly in the OAC7 group (57.1% in smokers vs 83.6% in non-smokers; P = 0.06). Adverse effects rate were similar between both groups.

CONCLUSION: Short-term efficacy of triple therapy with OAC for 7 d is comparable to 14 d in this high-prevalence population. Longer follow-up, and studies focused to some subgroups of patients (smokers and non-ulcer patients) are necessary to support widespread use of 7-d instead of 10-14-d triple therapy in a developing country like Chile.

Expression of Helicobacter pylori urease subunit B gene in transgenic rice

Helicobacter pyloriureB antigen gene was cloned to the 5′-end of gus (β-glucuronidase) reporter gene between CaMV35S promoter and the octopine synthase (OCS) terminator in the plasmid, pCAMBIA13011. It was then introduced into rice genome by Agrobacterium-mediated transformation. A total of 30 regenerated plants with hygromycin resistance were obtained in the selection media. The putative transgenic individuals were tested for the presence of ureB in the nuclear genome of rice plants by PCR analysis. Expression of ureB gene in rice plants was verified by RT-PCR and Western blot analysis using polyclonal human antiserum for transcription and translation levels respectively. These results provide a basis for further studies on the accumulation level of UreB recombinant protein in transgenic rice and potential utilization of transgenic rice for delivery of edible vaccines against Helicobacter pylori.

Pretreatment with Lactobacillus- and Bifidobacterium-containing yogurt can improve the efficacy of quadruple therapy in eradicating residual Helicobacter pylori infection after failed triple therapy

BACKGROUND

Lactobacillus- and Bifidobacterium-containing yogurt (AB-yogurt) can suppress Helicobacter pylori. Improvement of the eradication rate by quadruple therapy of residual H. pylori after failed triple therapy is needed.

OBJECTIVE

We tested whether prior treatment with AB-yogurt improved the efficacy of quadruple therapy in eradicating residual H. pylori after failed triple therapy.

DESIGN

One hundred thirty-eight patients in whom triple therapy failed were enrolled for a culture study of H. pylori to assess antimicrobial resistance. These patients were then randomly assigned in equal numbers to either a yogurt-plus-quadruple therapy group or a quadruple therapy-only group. The patients received 1 wk of quadruple therapy with or without a 4-wk pretreatment with AB-yogurt (400 mL/d). In the yogurt-plus-quadruple group, excessive delta(13)CO(2)/mL values of the (13)C-urea breath test were collected before and every 2 wk during the 4-wk ingestion of yogurt. For both groups, a (13)C-urea breath test was conducted > or =6 wk after the quadruple therapy to assess the outcome of residual H. pylori eradication.

RESULTS

For the patients in the yogurt-plus-quadruple therapy group infected with either antibiotic-sensitive or -resistant H. pylori, the excessive delta(13)CO(2)/mL values of the (13)C-urea breath test were significantly decreased after the 4-wk ingestion of AB-yogurt (P < 0.0001). The yogurt-plus-quadruple therapy group had a higher H. pylori eradication rate than did the quadruple therapy-only group (intention-to-treat analysis: 85% compared with 71.1%, P < 0.05; per-protocol analysis: 90.8% compared with 76.6%, P < 0.05).

CONCLUSION

A 4-wk pretreatment with AB-yogurt can decrease H. pylori loads despite antimicrobial resistance, thus improving the efficacy of quadruple therapy in eradicating residual H. pylori.

Non-antibiotic therapies for Helicobacter pylori infection

Despite years of experience with Helicobacter pylori treatment, the ideal regimen for treating the infection has not been found. The most effective eradication treatment is the combination of a proton pump inhibitor with antibiotics, but 10-20% of the patients fail to obtain eradication of the infection. Antibiotic resistance is a major factor affecting the outcome of treatment. Non-antibiotic therapies, including phytomedicines, probiotics, and antioxidants, have been increasingly investigated as potential alternatives for the treatment of H. pylori. In this article, we review the non-antibiotic therapies for H. pylori infection.

Novel therapeutic targets in Helicobacter pylori

The failure of current regimens to treat the gastric pathogen Helicobacter pylori is a growing problem. Responsible for gastritis and peptic ulcer disease, and designated as a Class 1 carcinogen, its presence in up to 90% of the population of the developing world makes its treatment a primary concern. The use of genomic, proteomic and transcriptomic data to determine essential gene products as targets for novel therapeutic agents is of key interest in this research. This review describes how such data can be obtained, evaluated and eventually used as a basis for the development of both vaccine and novel anti-helicobacter agents. It indicates both past successes and possible new avenues to exploit the increased availability of such data, whilst also examining the limitations of such approaches.

In vitro activity of fosfomycin alone and in combination with amoxicillin, clarithromycin and metronidazole against Helicobacter pylori compared with combined clarithromycin and metronidazole

In order to evaluate the suitability of fosfomycin in combination with other agents for the treatment of Helicobacter pylori infections, the susceptibility profiles of 65 H. pylori strains were determined against multiple antimicrobial agents and combinations thereof using the agar dilution method. For fosfomycin alone, the range of minimum inhibitory concentration (MIC) results and the MICs at which 50% and 90% of strains were inhibited were 0.5-32 microg/ml and 2 and 4 microg/ml, respectively. For the combination of fosfomycin with amoxicillin, clarithromycin or metronidazole, the means calculated for the minimum and maximum fractional inhibitory concentration index were 0.70-1.17 and 1.15-2.03, respectively, suggesting partial synergy or indifference in the majority of strains. The combination of clarithromycin and metronidazole showed synergistic activity against 14 of 28 H. pylori strains tested. The in vitro activity results suggest the combination of fosfomycin with either amoxicillin or clarithromycin may be a promising alternative for the treatment of H. pylori infection. However, the clinical efficacy of these regimens remains to be investigated.

Posttreatment 13C-urea breath test is predictive of antimicrobial resistance to H. pylori after failed therapy

OBJECTIVE

We tested whether a 13C-urea breath test can predict antimicrobial resistance of Helicobacter pylori (H. pylori).

METHODS

Seventy patients who had failed triple eradication therapy and 108 untreated H. pylori-infected patients were given a 13C-urea breath test, endoscopy for culture of H. pylori, and assessment of clarithromycin resistance. The patients who had failed triple therapy then received 1 week of quadruple therapy to eradicate residual H. pylori.

RESULTS

The posttreatment value of the 13C-urea breath test expressed as excessive delta13CO2 per ml (ECR) was higher in patients with residual H. pylori with clarithromycin resistance than in those without (23.8 vs 10.6; P<.0001). With a cutoff of ECR >or< or =15, the 13C-urea breath test was 88.6% sensitive and 88.9% specific in predicting clarithromycin resistance of residual H. pylori. The H. pylori eradication rate of the rescue regimen was higher for patients with a posttreatment ECR of the 13C-urea breath test < or =15 than for those with a value >15 (93.8% vs 73.3%; P<.05). In contrast, in treatment-naive H. pylori-infected patients, the pretreatment value of the 13C-urea breath test did not differ between patients infected with clarithromycin-resistant or-sensitive isolates (P>.05).

CONCLUSION

The posttreatment value of the 13C-urea breath test is predictive of clarithromycin resistance in residual H. pylori after failed triple therapy and predicts efficacy of the rescue regimen. The value of the noninvasive test is promising for primary care physicians who need to select a rescue regimen without invasive H. pylori culture.

Orally administered CpG oligodeoxynucleotide induces production of CXC and CC chemokines in the gastric mucosa and suppresses bacterial colonization in a mouse model of Helicobacter pylori infection

Bacterial DNA and unmethylated CpG oligodeoxynucleotides (CpG ODN) are known to be potent stimulators of the innate immune system in vitro and in vivo. We therefore investigated if oral administration of CpG ODN could enhance innate immunity in the gastric mucosa and control the extent of Helicobacter pylori infection in mice. Intragastric administration of a single dose of CpG ODN significantly increased local production of the CC chemokines macrophage inflammatory protein 1alpha (MIP-1alpha), MIP-1beta, and RANTES and the CXC chemokine gamma interferon-inducible protein 10 in the stomach and/or the small intestine. Importantly, intragastric administration of CpG ODN to mice with an already established H. pylori infection, in the absence of any coadministered antigen, was found to reduce the bacterial load in the stomach compared to the load in H. pylori-infected control mice, while similar administration of non-CpG ODN had no effect on the bacterial load. The reduction in the bacterial numbers in the stomachs of mice treated with CpG ODN was associated with enhanced infiltration of immune cells and increased RANTES production in the gastric mucosa compared to the infiltration of immune cells and RANTES production in H. pylori-infected control animals. These findings suggest that intragastric administration of CpG ODN without antigen codelivery may represent a valuable strategy for induction of innate immunity against H. pylori infection.

Beta-lactamase inhibitor enhances Helicobacter pylori eradication rate

OBJECTIVES

One-week triple therapy, a combination of acid suppression with two antibiotics, is the gold standard for anti-Helicobacter pylori treatment. There is increasing evidence of H. pylori resistance to classical triple therapy. Recently, it was reported that the amoxicillin-clavulanate combination had a slightly higher activity than amoxicillin alone against H. pylori, and that beta-lactamase inhibitors had 'in-vitro' antibacterial activity against H. pylori.

SETTING

To evaluate the efficacy of 1 week triple therapy omeprazole, clarithromycin and amoxicillin plus clavulanate compared with omeprazole, clarithromycin and amoxicillin for H. pylori eradication. The study was open randomized.

SUBJECTS

Sixty dyspeptic patients (36 male, 24 female; mean age 53 +/- 9 years) with Helicobacter pylori infection never treated before, were enrolled and randomly assigned to two different 7-day triple therapies: (i) (n = 30) amoxicillin 875 mg plus clavulanic acid 125 mg b.i.d., clarithromycin 500 mg b.i.d., omeprazole 20 mg b.i.d. (ACCO); (ii) (n = 30) amoxicillin 1 g b.i.d., clarithromycin 500 mg b.i.d., omeprazole 20 mg b.i.d. (ACO). Bacterial eradication was assessed by 13C-urea breath test 4-6 weeks after therapy. Information on gastrointestinal symptoms and antibiotic-related side-effects were recorded using a questionnaire.

RESULTS

All patients completed the study. A significantly higher H. pylori eradication rate with ACCO compared with ACO: (26/30) 86.6 vs. (20/30) 66.6%, respectively (P < 0.05) were observed. No major side-effects were reported, whilst 8% patients complained of mild side-effects; no significant differences were noted between the two groups.

CONCLUSIONS

Our results suggest that amoxicillin and clavulanate in combination achieve a higher H. pylori eradication rate than amoxicillin alone, without any increase in side-effects. The combination of amoxicillin and clavulanate may represent an alternative therapeutic scheme for the treatment of H. pylori infection.

Quadruple therapy containing amoxicillin and tetracycline is an effective regimen to rescue failed triple therapy by overcoming the antimicrobial resistance of Helicobacter pylori

AIM

To identify optimal antibiotics for second-line quadruple therapy of Helicobacter pylori after failed 1-week triple therapy.

METHODS

One hundred patients were enrolled in this study after the failure of 1-week triple therapy. They were randomized to receive 1-week quadruple therapy consisting of amoxicillin, omeprazole and bismuth salts, plus either metronidazole or tetracycline. Before quadruple therapy, the H. pylori culture of each patient was tested for metronidazole resistance or clarithromycin resistance by E-test. Six weeks later, an endoscopy or 13C-urea breath test was used to define the success of H. pylori eradication.

RESULTS

The H. pylori eradication rates by intention-to-treat and per protocol analysis were higher in the tetracycline group than in the metronidazole group (intention-to-treat: 78% vs. 58%, P < 0.05; per protocol: 89% vs. 67%, P < 0.05). In the metronidazole group, but not in the tetracycline group, the per protocol eradication rate of quadruple therapy was lower for the infected isolates with metronidazole resistance than for those without metronidazole resistance (77% vs. 33%, P < 0.05).

CONCLUSION

Quadruple therapy, including tetracycline and amoxicillin, improves the H. pylori eradication rate after failed triple therapy.