Treatment of Helicobacter pylori infection 2011

Helicobacter pylori adhesins: HpaA a potential antigen in experimental vaccines for H. pylori

BACKGROUND

Helicobacter pylori is a gram-negative bacterium involved in many gastric pathologies such as ulcers and cancers. Although the treatment for this infection has existed for several years, the development of a vaccine is nevertheless necessary to reduce the severe forms of the disease. For more than three decades, many advances have been made particularly in the understanding of virulence factors as well as the pathogenesis of gastric diseases caused by H. pylori. Among these key virulence factors, specific antigens have been identified: Urease, Vacuolating cytotoxin A (VacA), Cytotoxin-associated gene A (CagA), Blood group antigen-binding adhesin (BabA), H. pylori adhesin A (HpaA), and others.

OBJECTIVES

This review will focus on H. pylori adhesins, in particular, on HpaA and on the current knowledge of H. pylori vaccines.

METHODS

All of the information included in this review was retrieved from published studies on H. pylori adhesins in H. pylori infections.

RESULTS

These proteins, used in their native or recombinant forms, induce protection against H. pylori in experimental animal models.

CONCLUSION

H. pylori adhesins are known to be promising candidate vaccines against H. pylori. Future research should be carried out on adhesins, in particular, on HpaA.

MicroRNA Modulation of Host Immune Response and Inflammation Triggered by Helicobacter pylori

Helicobacter pylori (H. pylori) remains the most-researched etiological factor for gastric inflammation and malignancies. Its evolution towards gastric complications is dependent upon host immune response. Toll-like receptors (TLRs) recognize surface and molecular patterns of the bacterium, especially the lipopolysaccharide (LPS), and act upon pathways, which will finally lead to activation of the nuclear factor-kappa B (NF-kB), a transcription factor that stimulates release of inflammatory cytokines. MicroRNAs (MiRNAs) finely modulate TLR signaling, but their expression is also modulated by activation of NF-kB-dependent pathways. This review aims to focus upon several of the most researched miRNAs on this subject, with known implications in host immune responses caused by H. pylori, including let-7 family, miRNA-155, miRNA-146, miRNA-125, miRNA-21, and miRNA-221. TLR-LPS interactions and their afferent pathways are regulated by these miRNAs, which can be considered as a bridge, which connects gastric inflammation to pre-neoplastic and malignant lesions. Therefore, they could serve as potential non-invasive biomarkers, capable of discriminating H. pylori infection, as well as its associated complications. Given that data on this matter is limited in children, as well as for as significant number of miRNAs, future research has yet to clarify the exact involvement of these entities in the progression of H. pylori-associated gastric conditions.

The Relationship between Toll-like Receptors and Helicobacter pylori-Related Gastropathies: Still a Controversial Topic

Innate immunity represents the first barrier against bacterial invasion. Toll-like receptors (TLRs) belong to the large family of pattern recognition receptors (PRRs), and their activation leads to the induction of inflammatory cytokines, chemokines, antigen-presenting molecules, and costimulatory molecules. Recent studies have focused on identifying the association between TLRs and Helicobacter pylori- (H. pylori-) related diseases. Therefore, this minireview focuses on assessing the role of these TLRs in the development of H. pylori-related gastropathies. Both TLR2 and TLR were found to be involved in H. pylori LPS recognition, with contradictory results most likely due to both the inability to obtain pure LPS in experimental studies and the heterogeneity of the bacterial LPS. In addition, TLR2 was found to be the most extensively expressed gene among all the TLRs in gastric tumors. High levels of TLR4 were also associated with a higher risk of gastric cancer. TLR5 was initially associated with the recognition of H. pylori flagellin, but it seems that this bacterium has developed mechanisms to escape this recognition representing an important factor involved in the persistence of this infection and subsequent carcinogenesis. TLR9, the only TLR with both anti- and proinflammatory roles, was involved in the recognition of H. pylori DNA. The dichotomous role of TLR9, promoting or suppressing the infection, depends on the gastric environment. Recently, TLR7 and TLR8 were shown to recognize purified H. pylori RNA, thereby inducing proinflammatory cytokines. TLR1 and TLR10 gene polymorphisms were associated with a higher risk for gastric cancer in H. pylori-infected individuals. Different gene polymorphisms of these TLRs were found to be associated with gastric cancer depending mostly on ethnicity. Further studies are required in order to develop preventive and therapeutic strategies against H. pylori infections based on the functions of TLRs.

Herpes Simplex Virus Type 1 and Other Pathogens are Key Causative Factors in Sporadic Alzheimer's Disease

This review focuses on research in epidemiology, neuropathology, molecular biology, and genetics regarding the hypothesis that pathogens interact with susceptibility genes and are causative in sporadic Alzheimer's disease (AD). Sporadic AD is a complex multifactorial neurodegenerative disease with evidence indicating coexisting multi-pathogen and inflammatory etiologies. There are significant associations between AD and various pathogens, including Herpes simplex virus type 1 (HSV-1), Cytomegalovirus, and other Herpesviridae, Chlamydophila pneumoniae, spirochetes, Helicobacter pylori, and various periodontal pathogens. These pathogens are able to evade destruction by the host immune system, leading to persistent infection. Bacterial and viral DNA and RNA and bacterial ligands increase the expression of pro-inflammatory molecules and activate the innate and adaptive immune systems. Evidence demonstrates that pathogens directly and indirectly induce AD pathology, including amyloid-β (Aβ) accumulation, phosphorylation of tau protein, neuronal injury, and apoptosis. Chronic brain infection with HSV-1, Chlamydophila pneumoniae, and spirochetes results in complex processes that interact to cause a vicious cycle of uncontrolled neuroinflammation and neurodegeneration. Infections such as Cytomegalovirus, Helicobacter pylori, and periodontal pathogens induce production of systemic pro-inflammatory cytokines that may cross the blood-brain barrier to promote neurodegeneration. Pathogen-induced inflammation and central nervous system accumulation of Aβ damages the blood-brain barrier, which contributes to the pathophysiology of AD. Apolipoprotein E4 (ApoE4) enhances brain infiltration by pathogens including HSV-1 and Chlamydophila pneumoniae. ApoE4 is also associated with an increased pro-inflammatory response by the immune system. Potential antimicrobial treatments for AD are discussed, including the rationale for antiviral and antibiotic clinical trials.

Efficacy of 7-Day and 14-Day Bismuth-Containing Quadruple Therapy and 7-Day and 14-Day Moxifloxacin-Based Triple Therapy as Second-Line Eradication for Helicobacter pylori Infection

BACKGROUND/AIMS

Bismuth-containing quadruple and moxifloxacin-based triple regimens are recommended as second-line therapy for Helicobacter pylori infection. The aim of this study was to compare the efficacy of each regimen.

METHODS

From August 2004 to October 2012, a total of 949 patients (mean age, 54.32±12.08 years; male, 49.4%) who failed H. pylori eradication with a standard triple regimen were included. Patients treated with a bismuth-containing quadruple regimen for 7 and 14 days were designated as 7-BMT and 14-BMT, respectively, and those treated with a moxifloxacin-based triple regimen for 7 and 14 days were designated as 7-MA and 14-MA, respectively. H. pylori eradication was confirmed using the (13)C-urea breath test, rapid urease test or histology.

RESULTS

The eradication rates by 7-BMT, 14-BMT, 7-MA, and 14-MA were 66.4% (290/437), 71.1% (113/159), 53.1% (51/96), and 73.5% (189/257), respectively, by intention-to-treat analysis (ITT) and 76.5% (284/371), 83.8% (109/130), 55.6% (50/90), and 80.6% (187/232), respectively, by per-protocol analysis (PP). The eradication rates were higher in 14-BMT than 7-BMT by the ITT and PP analyses (p=0.277 and p=0.082, respectively). The 14-BMT and 14-MA treatments showed similar efficacies by ITT and PP (p=0.583 and p=0.443, respectively).

CONCLUSIONS

The 7-BMT, 14-BMT, and 14-MA treatments showed similar and suboptimal efficacies. In both regimens, extending the duration of treatment may be reasonable considering the high level of antibiotic resistance in Korea.

Antibiotic treatment for Helicobacter pylori: Is the end coming?

Infection with the Gram-negative pathogen Helicobacter pylori (H. pylori) has been associated with gastro-duodenal disease and the importance of H. pylori eradication is underscored by its designation as a group I carcinogen. The standard triple therapy consists of a proton pump inhibitor, amoxicillin and clarithromycin, although many other regimens are used, including quadruple, sequential and concomitant therapy regimens supplemented with metronidazole, clarithromycin and levofloxacin. Despite these efforts, current therapeutic regimens lack efficacy in eradication due to antibiotic resistance, drug compliance and antibiotic degradation by the acidic stomach environment. Antibiotic resistance to clarithromycin and metronidazole is particularly problematic and several approaches have been proposed to overcome this issue, such as complementary probiotic therapy with Lactobacillus. Other studies have identified novel molecules with an anti-H. pylori effect, as well as tailored therapy and nanotechnology as viable alternative eradication strategies. This review discusses current antibiotic therapy for H. pylori infections, limitations of this type of therapy and predicts the availability of newly developed therapies for H. pylori eradication.

Immunology and vaccines and nanovaccines for Helicobacter pylori infection

Helicobacter pylori infection is very common worldwide and is an important cause of gastritis, peptic ulcer disease, gastric mucosa-associated lymphoid tissue lymphoma, and gastric adenocarcinoma. Since the eradication requires treatment with multidrug regimens, prevention of primary infection by a suitable vaccine is attractive. Developing vaccines on the spot when and where an infection is breaking out might be possible, thanks to engineered nanoparticles. In this review, the nature of the host immune response to H. pylori infection is considered. We explain recent candidate vaccines and prophylactic or therapeutic immunization strategies for use against H. pylori. We also describe identification of different types of immune responses that may be related to protection against H. pylori infection. Thus, it seems that there is still a strong need to clarify the main protective immune response against H. pylori.

Rifabutin-based high-dose proton-pump inhibitor and amoxicillin triple regimen as the rescue treatment for Helicobacter pylori

BACKGROUND

Rifabutin has been known to be effective in multidrug-resistant Helicobacter pylori-harboring patients undergoing treatment failure for H. pylori infection.

AIM

To evaluate the efficacy of 7-day treatment regimen consisting rifabutin daily but increasing the dose of amoxicillin and lansoprazole in patients who have failed first and second eradication and to assess the side effect profiles in South Korea.

METHODS

From December 2007 to May 2013, 59 H. pylori-infected patients with two previous eradication failures were enrolled for this study prospectively. The eligible patients were randomly assigned to either group A or B. Group A received lansoprazole 30 mg bid, amoxicillin 1.0 g tid and rifabutin 150 mg bid during 7 days, whereas group B received lansoprazole 60 mg bid, amoxicillin 1.0 g tid and rifabutin 150 mg bid during 7 days.

RESULTS

In group A, H. pylori eradication was achieved in 25 (78.1%) of the 32 patients in the ITT analysis and in 25 (80.6%) of the 31 patients in the PP analysis. In group B, H. pylori eradication was achieved in 26 (96.3%) of the 27 patients in the ITT analysis and in 27 (100%) of the 26 patients in the PP analysis. There was statistically significant difference between the two groups in terms of the eradication rates in PP analysis (p = .047), whereas a marginally statistical significance was found in terms of the eradication rates in ITT analysis (p = .051). Reported side effects were mild, and treatment was well tolerated. No major changes in physical examination or in standard laboratory parameters were observed after treatment.

CONCLUSIONS

Rifabutin-based high-dose proton-pump inhibitor (PPI)-combined therapy as empirical rescue treatment is more effective than standard dose PPI-combined rifabutin-based therapy, safe and best tolerable in third-line therapy in the Korean population. The key to successful rescue therapy with rifabutin-amoxicillin-PPI regimen may be to increase doses of PPI.

Role of Toll-like receptors in Helicobacter pylori infection and immunity

The gram-negative bacterium Helicobacter pylori (H. pylori) infects the stomachs of approximately half of the world's population. Although infection induces an immune response that contributes to chronic gastric inflammation, the response is not sufficient to eliminate the bacterium. H. pylori infection causes peptic ulcers, gastric cancer and mucosa-associated lymphoid tissue lymphoma. Disease outcome is linked to the severity of the host inflammatory response. Gastric epithelial cells represent the first line of innate immune defence against H. pylori, and respond to infection by initiating numerous cell signalling cascades, resulting in cytokine induction and the subsequent recruitment of inflammatory cells to the gastric mucosa. Pathogen recognition receptors of the Toll-like receptor (TLR) family mediate many of these cell signalling events. This review discusses recent findings on the role of various TLRs in the recognition of H. pylori in distinct cell types, describes the TLRs responsible for the recognition of individual H. pylori components and outlines the influence of innate immune activation on the subsequent development of the adaptive immune response. The mechanistic identification of host mediators of H. pylori-induced pathogenesis has the potential to reveal drug targets and opportunities for therapeutic intervention or prevention of H. pylori-associated disease by means of vaccines or immunomodulatory therapy.

Is levofloxacin-based triple therapy an alternative for first-line eradication of Helicobacter pylori? A systematic review and meta-analysis

OBJECTIVES

To evaluate the available data on the efficacy and safety of levofloxacin-based triple therapy compared with standard triple therapy in first-line treatment for Helicobacter pylori infection.

METHODS

By searching MEDLINE, The Cochrane Central Register of Controlled Trials, and Web of Knowledge, two independent reviewers systemically identified randomized controlled trials comparing levofloxacin-based triple regimen with standard triple therapy for first-line treatment of H. pylori infection. The pooled risk ratios (RR) and 95% confidence intervals were calculated.

RESULTS

Overall, nine randomized controlled trials including 1275 patients have been treated with levofloxacin-based triple therapy and 1237 patients with standard regimen. Eradication rate in the levofloxacin-based therapy group was slightly higher than that in the standard triple therapy group regardless of treatment duration (80.2% vs. 77.4%, RR=1.03, 95% CI=0.94-1.13). Subgroup analysis related to different geographic areas found that efficacy of 7-day standard triple regimen was statistically superior to 7-day levofloxacin-based scheme in Asian group (RR=0.91, 95% CI=0.86-0.97), but levofloxacin-based triple therapy was predominant regardless of treatment time in European countries (RR=1.15, 95% CI=1.06-1.23). There was no significant difference between two groups in the incidence of overall adverse events or in the occurrence of discontinuing therapy due to side effects.

CONCLUSIONS

The 10-day levofloxacin-based triple therapy may be considered as an alternative for increasing cure rate of H. pylori infection in European areas. But in Asian countries, standard triple regimen is still superior to levofloxacin-based therapy as first-line regimen for H. pylori eradication.

Saccharomyces boulardii expresses neuraminidase activity selective for α2,3-linked sialic acid that decreases Helicobacter pylori adhesion to host cells

Helicobacter pylori is a major causative agent of gastritis and peptic ulcer disease and is an established risk factor for gastric malignancy. Antibiotic combination therapy can eradicate H. pylori. As these same regimens can evoke adverse effects and resistance, new alternative therapies or adjunctive treatments are needed. A probiotic approach may provide a novel strategy for H. pylori treatment. In the current study, two probiotic bacteria, Lactobacillus acidophilus and Lactobacillus reuteri, and a probiotic yeast, Saccharomyces boulardii, were evaluated for their ability to influence H. pylori viability, adherence to gastric and duodenal cells, as well as the effect of S. boulardii on cell surface expression of sialic acid. Our results indicate that S. boulardii contains neuraminidase activity selective for α(2-3)-linked sialic acid. This neuraminidase activity removes surface α(2-3)-linked sialic acid, the ligand for the sialic acid-binding H. pylori adhesin, which in turn, inhibits H. pylori adherence to duodenal epithelial cells.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Clinical evaluation of twenty cases of heterotopic gastric mucosa of upper esophagus during five-year observation, using gastroscopy in combination with histopathological and microbiological analysis of biopsies

Aim of the study

Heterotopic gastric mucosa of the upper esophagus (HGMUE) may be connected with disorders of the upper gastrointestinal tract, exacerbated by Helicobacter pylori. Furthermore, HGMUE may be the origin of malignant progression to cervical esophageal carcinoma.

Material and methods

In this work, 20 patients with diagnosed heterotopic gastric mucosa of the upper esophagus (HGMUE) were subjected to 5-year follow-up to determine the extent and structure of histopathological changes within HGMUEs, as well as HGMUE dysplasia and metaplasia, and risk of their malignant transformation. As a diagnostic tool to describe localization, form, size and surface feature of HGMUEs, endoscopy was used. At the same time, the biopsies were collected for histopathological and microbiological analysis.

Results

In examined patients, HGMUEs were associated with inflammation, chronic gastritis, hiatus hernia, duodenal bulb erosion and ulcer and infection of H. pylori. Intestinal metaplasia and low grade dysplasia were also indicated. During 5 years of observation, both the clinical and histopathological image of diagnosed HGMUEs was stable. The patients with detected presence of H. pylori were treated with triple or quadruple therapy.

These results show that HGMUEs may be associated with severe complications in the gastrointestinal tract, such as infection by H. pylori, hiatus hernia or duodenal ulcer. Although dysplasias and metaplasias found in diagnosed HGMUEs were not very numerous and relatively stable both clinically and histopathologically, at the present stage of the study we cannot exclude the possibility of HGMUE malignant transformation.

[Clinical practice guideline on the management of patients with dyspepsia. Update 2012]

The aim of the Clinical Practice Guideline (CPG) on the Management of Patients with Dyspepsia is to generate recommendations on the optimal approach to dyspepsia in the primary care and specialized outpatient setting. The main objective of this CPG is to help to optimize the diagnostic process, identifying patients with a low risk of a serious organic disease (mainly tumoral), who could be safely managed without the need for invasive diagnostic tests and/or referral to a specialist. The importance of this aim lies in the need to accurately diagnose patients with esophagogastric cancer and correctly treat peptic ulcer while, at the same time, reduce negative endoscopies in order to appropriately use the available healthcare resources. This CPG reviews the initial strategies that can be used in patients with uninvestigated dyspepsia and evaluates the possible decision to begin empirical therapy or to investigate the existence of a lesion that could explain the symptoms. This CPG also discusses functional dyspepsia, which encompasses all patients with dyspepsia with no demonstrable cause on endoscopy. Recommendations for the diagnosis and treatment of peptic ulcer and Helicobacter pylori infection are also made. To classify the scientific evidence and strengthen the recommendations, the GRADE (Grading of Recommendations Assessment, Development and Evaluation Working Group) system has been used (http://www.gradeworkinggroup.org/).

Helicobacter pylori eradication with ecabet sodium, omeprazole, amoxicillin, and clarithromycin versus bismuth, omeprazole, amoxicillin, and clarithromycin quadruple therapy: a randomized, open-label, phase IV trial

BACKGROUND

Helicobacter pylori infection is a substantial public health problem and plays etiological role in the pathogenesis of many gastroduodenal disorders. The addition of ecabet sodium is proven to improve the efficacy of the standard triple therapy. Our aim was to assess the efficacy and safety of ecabet sodium-containing quadruple therapy versus 10-day bismuth-containing quadruple therapy for H. pylori eradication.

MATERIALS AND METHODS

We did a randomized, open-label, phase IV trial in four cities (eight sites) in China, comparing the efficacy and safety of 10-days ecabet sodium-containing versus bismuth-containing quadruple therapy in adults with H. pylori infection. Eligible patients were randomly assigned treatment and monitored H. pylori eradication by negative [13C]/[14C] urea breath test 28 days after the treatment as the primary outcome. Symptoms improvement and side effects were the secondary outcome.

RESULTS

A total of 311 H. pylori-positive subjects were enrolled: 155 were assigned ecabet sodium quadruple therapy and 156 bismuth quadruple therapy. The eradication rates with ecabet sodium-containing and bismuth-containing quadruple regimens were 68.4% (106/155) and 68.0% (106/156) p = .9339 intention-to-treat (ITT) and 75.4% (104/138) and 77.0% (104/135) p = .7453 per-protocol (PP), respectively. The eradication rates for the ecabet sodium quadruple regimen differed significantly between cities (e.g., 81.2% ITT and 89.6% PP in Shanghai and 50% ITT and 53.5% PP in Xi'an). The symptom improvements and safety profiles were also similar for both treatments.

CONCLUSIONS

Neither 10-day Ecabet sodium-containing quadruple therapy or 10-day bismuth-containing quadruple therapy can be recommended as empiric therapy in cities with high antibiotic resistance rate of China.

[Clinical practice guideline on the management of patients with dyspepsia. Update 2012]

The aim of the Clinical Practice Guideline (CPG) on the Management of Patients with Dyspepsia is to generate recommendations on the optimal approach to dyspepsia in the primary care and specialized outpatient setting. The main objective of this CPG is to help to optimize the diagnostic process, identifying patients with a low risk of a serious organic disease (mainly tumoral), who could be safely managed without the need for invasive diagnostic tests and/or referral to a specialist. The importance of this aim lies in the need to accurately diagnose patients with esophagogastric cancer and correctly treat peptic ulcer while, at the same time, reduce negative endoscopies in order to appropriately use the available healthcare resources.This CPG reviews the initial strategies that can be used in patients with uninvestigated dyspepsia and evaluates the possible decision to begin empirical therapy or to investigate the existence of a lesion that could explain the symptoms. This CPG also discusses functional dyspepsia, which encompasses all patients with dyspepsia with no demonstrable cause on endoscopy. Recommendations for the diagnosis and treatment of peptic ulcer and Helicobacter pylori infection are also made. To classify the scientific evidence and strengthen the recommendations, the GRADE (Grading of Recommendations Assessment, Development and Evaluation Working Group) system has been used (http://www.gradeworkinggroup.org/).

Large scale screening of commonly used Iranian traditional medicinal plants against urease activity

Background and purpose of the study

H. pylori infection is an important etiologic impetus usually leading to gastric disease and urease enzyme is the most crucial role is to protect the bacteria in the acidic environment of the stomach. Then urease inhibitors would increase sensitivity of the bacteria in acidic medium.

Methods

137 Iranian traditional medicinal plants were examined against Jack bean urease activity by Berthelot reaction. Each herb was extracted using 50% aqueous methanol. The more effective extracts were further tested and their IC₅₀ values were determined.

Results

37 plants out of the 137 crude extracts revealed strong urease inhibitory activity (more than 70% inhibition against urease activity at 10 mg/ml concentration). Nine of the whole studied plants crude extracts were found as the most effective with IC₅₀ values less than 500 μg/ml including; Rheum ribes, Sambucus ebulus, Pistachia lentiscus, Myrtus communis, Areca catechu, Citrus aurantifolia, Myristica fragrans, Cinnamomum zeylanicum and Nicotiana tabacum.

Conclusions

The most potent urease inhibitory was observed for Sambucus ebulus and Rheum ribes extracts with IC₅₀ values of 57 and 92 μg/ml, respectively.

Levofloxacin/amoxicillin-based schemes vs quadruple therapy for Helicobacter pylori eradication in second-line

Worldwide prevalence of Helicobacter pylori (H. pylori) infection is approximately 50%, with the highest being in developing countries. We compared cure rates and tolerability (SE) of second-line anti-H. pylori levofloxacin/amoxicillin (LA)-based triple regimens vs standard quadruple therapy (QT). An English language literature search was performed up to October 2010. A meta-analysis was performed including randomized clinical trials comparing 7- or 10-d LA with 7-d QT. In total, 10 articles and four abstracts were identified. Overall eradication rate in LA was 76.5% (95% CI: 64.4%-97.6%). When only 7-d regimens were included, cure rate was 70.6% (95% CI: 40.2%-99.1%), whereas for 10-d combinations, cure rate was significantly higher (88.7%; 95% CI: 56.1%-109.9%; P < 0.05). Main eradication rate for QT was 67.4% (95% CI: 49.7%-67.9%). The 7-d LA and QT showed comparable efficacy [odds ratio (OR): 1.09; 95% CI: 0.63-1.87], whereas the 10-d LA regimen was significantly more effective than QT (OR: 5.05; 95% CI: 2.74-9.31; P < 0.001; I(2) = 75%). No differences were reported in QT eradication rates among Asian and European studies, whereas LA regimens were more effective in European populations (78.3% vs 67.7%; P = 0.05). Incidence of SE was lower in LA therapy than QT (OR: 0.39; 95% CI: 0.18-0.85; P = 0.02). A higher rate of side effects was reported in Asian patients who received QT. Our findings support the use of 10-d LA as a simple second-line treatment for H. pylori eradication with an excellent eradication rate and tolerability. The optimal second-line alternative scheme might differ among countries depending on quinolone resistance.

Antibacterial activities of liposomal linolenic acids against antibiotic-resistant Helicobacter pylori

Helicobacter pylori (H. pylori) infection with its vast prevalence is responsible for various gastric diseases including gastritis, peptic ulcers, and gastric malignancy. While effective, current treatment regimens are challenged by a fast-declining eradication rate due to the increasing emergence of H. pylori strains resistant to existing antibiotics. Therefore, there is an urgent need to develop novel antibacterial strategies against H. pylori. In this study, we developed a liposomal nanoformulation of linolenic acid (LipoLLA) and evaluated its bactericidal activity against resistant strains of H. pylori. Using a laboratory strain of H. pylori, we found that LipoLLA was effective in killing both spiral and coccoid forms of the bacteria via disrupting bacterial membranes. Using a metronidazole-resistant strain of H. pylori and seven clinically isolated strains, we further demonstrated that LipoLLA eradicated all strains of the bacteria regardless of their antibiotic resistance status. Furthermore, under our experimental conditions, the bacteria did not develop drug resistance when cultured with LipoLLA at various sub-bactericidal concentrations, whereas they rapidly acquired resistance to both metronidazole and free linolenic acid (LLA). Our findings suggest that LipoLLA is a promising antibacterial nanotherapeutic to treat antibiotic-resistant H. pylori infection.

Review article: biofilm formation by Helicobacter pylori as a target for eradication of resistant infection

BACKGROUND

Helicobacter pylori is one of the most common causes of bacterial infection in humans. Resistance of this infection to conventional therapies has suggested the role of a biofilm-growing bacterium, which is recalcitrant to many antimicrobial agents.

AIM

To review the current knowledge on biofilm formation by H. pylori and to discuss the implications of this behaviour in the context of human infections and their treatment.

RESULTS

Scanning electron microscopy analysis of gastric biopsies of infected patients demonstrated that H. pylori forms biofilm on the gastric mucosa epithelium. Adaptation to the biofilm environment may produce many persister cells, namely dormant cells, which are highly tolerant to antimicrobials that could account for the recalcitrance of H. pylori infections in vivo. Resistant H. pylori infection has become increasingly common with triple or quadruple therapy, even in the presence of H. pylori strains susceptible to all antibiotics. The mucolytic and thiol-containing antioxidant N-acetylcysteine, associated with antibiotics, was successfully used in clinic for therapy of patients with chronic respiratory tract infections. Consistently, N-acetylcysteine treatment prior to starting antibiotic therapy allowed the disappearance of gastric biofilm in all patients in whom H. pylori was eradicated.

CONCLUSION

Effective strategies targeting H. pylori biofilm infections are possible, through the use of substances degrading components of the biofilm.

Helicobacter pylori Eradication Therapy: Current Availabilities

Background. Though Helicobacter pylori (HP) infections have progressively declined throughout most of the industrialized countries, a gradual increase in failure of HP eradication treatments is observed. Aim. To critically review evidence on the efficacy of the therapeutic availabilities for HP eradication, as yet. Methods. A selection of Clinical Trials, Systematic Reviews and Meta-analyses within the time period 2010–2012, was performed through a Medline search. Previous references were included when basically supporting the first selection. Results. An increasing rise in HP resistance rates for antimicrobial agents is currently observed. Further causes of HP treatment failure include polymorphisms of the CYP 2C19, an increased body mass index (BMI), smoking, poor compliance and re-infections. Alternative recent approaches to standard triple therapy have been attempted to increase the eradication rate, including bismuth-containing quadruple therapy, non-bismuth containing quadruple therapy, sequential therapy and levofloxacin-containing regimens. Conclusions. The main current aims should be the maintenance of a high eradication rate (>85%) of HP and the prevention of any increase in antimicrobial resistance. In the next future, the perspective of a tailored therapy could optimize eradication regimens within the different countries.

Efficacy of 5-day levofloxacin-containing concomitant therapy in eradication of Helicobacter pylori infection

BACKGROUND & AIMS

Helicobacter pylori have become resistant to antimicrobial agents, reducing eradication rates. A 10-day sequential regimen that contains levofloxacin was efficient, safe, and cost saving in eradicating H pylori infection in an area with high prevalence of clarithromycin resistance. We performed a noninferiority randomized trial to determine whether a 5-day levofloxacin-containing quadruple concomitant regimen was as safe and effective as the 10-day sequential regimen in eradicating H pylori in previously untreated patients.

METHODS

We randomly assigned patients with H pylori infection to groups that were given 5 days of concomitant therapy (esomeprazole 40 mg twice daily, amoxicillin 1 g twice daily, levofloxacin 500 mg twice daily, and tinidazole 500 mg twice daily; n = 90) or 10 days of sequential therapy (esomeprazole 40 mg twice daily, amoxicillin 1g twice daily for 5 days followed by esomeprazole 40 mg twice daily, levofloxacin 500 mg twice daily, and tinidazole 500 mg twice daily for 5 more days; n = 90). Antimicrobial resistance was assessed by the E-test. Efficacy, adverse events, and costs were determined.

RESULTS

Intention-to-treat analysis showed similar eradication rates for concomitant (92.2%; 95% confidence interval [CI], 84.0%-95.8%) and sequential therapies (93.3%; 95% CI, 86.9%-97.3%). Per-protocol eradication results were 96.5% (95% CI, 91%-99%) for concomitant therapy and 95.5% for sequential therapy (95% CI, 89.6%-98.5%). The differences between sequential and concomitant treatments were 1.1% in the intention-to-treat study (95% CI; -7.6% to 9.8%) and -1.0% in the per-protocol analysis (95% CI; -8.0% to 5.9%). The prevalence of antimicrobial resistance and incidence of adverse events were comparable between groups. Concomitant therapy cost $9 less than sequential therapy.

CONCLUSIONS

Five days of levofloxacin-containing quadruple concomitant therapy is as effective and safe, and less expensive, in eradicating H pylori infection than 10 days of levofloxacin-containing sequential therapy.

The Optimal First-Line Therapy of Helicobacter pylori Infection in Year 2012

This paper reviews the literature about first-line therapies for H. pylori infection in recent years. First-line therapies are facing a challenge because of increasing treatment failure due to elevated antibiotics resistance. Several new treatment strategies that recently emerged to overcome antibiotic resistance have been surveyed. Alternative first-line therapies include bismuth-containing quadruple therapy, sequential therapy, concomitant therapy, and hybrid therapy. Levofloxacin-based therapy shows impressive efficacy but might be employed as rescue treatment due to rapidly raising resistance. Rifabutin-based therapy is also regarded as a rescue therapy. Several factors including antibiotics resistance, patient compliance, and CYP 2C19 genotypes could influence the outcome. Clinicians should use antibiotics according to local reports. It is recommended that triple therapy should not be used in areas with high clarithromycin resistance or dual clarithromycin and metronidazole resistance.

Rescue Therapy for Helicobacter pylori Infection 2012

Helicobacter pylori infection is the main cause of gastritis, gastroduodenal ulcer disease, and gastric cancer. After 30 years of experience in H. pylori treatment, however, the ideal regimen to treat this infection has still to be found. Nowadays, apart from having to know well first-line eradication regimens, we must also be prepared to face treatment failures. In designing a treatment strategy, we should not only focus on the results of primary therapy alone but also on the final-overall-eradication rate. The choice of a "rescue" treatment depends on which treatment is used initially. If a first-line clarithromycin-based regimen was used, a second-line metronidazole-based treatment (quadruple therapy) may be used afterwards, and then a levofloxacin-based combination would be a third-line "rescue" option. Alternatively, it has recently been suggested that levofloxacin-based "rescue" therapy constitutes an encouraging 2nd-line strategy, representing an alternative to quadruple therapy in patients with previous PPI-clarithromycin-amoxicillin failure, with the advantage of efficacy, simplicity and safety. In this case, quadruple regimen may be reserved as a 3rd-line "rescue" option. Even after two consecutive failures, several studies have demonstrated that H. pylori eradication can finally be achieved in almost all patients if several "rescue" therapies are consecutively given.

Variability in Prevalence ofHelicobacter pyloriStrains Resistant to Clarithromycin and Levofloxacin in Southern Poland

Background. An increasing resistance ofHelicobacter pyloristrains to antimicrobial agents is the serious therapeutic problem. The aim of this study was to compare the primary and secondary resistance ofH. pyloristrains isolated between 2006–2008 (data published) and 2009–2011 to clarithromycin and levofloxacin.Material and Methods. 220 dyspeptic patients (153 before treatment, 67 after), were enrolled in the study. 51H. pyloristrains were isolated. MIC values of clarithromycin and levofloxacin were determined by theE-test method. The statistical analysis was conducted with theχ2test with Yates correction at the 0.05 significance level (P≤0.05).Results. Between 2006 and 2008, 34% (39/115) ofH. pyloristrains were resistant to clarithromycin (primary 21% (19/90), secondary 80% (20/25)). 5% (6/115) of strains were resistant to levofloxacin (primary 2% (2/90), secondary 16% ((4/25); data published) Between 2009–2011, 22% (11/51) ofH. pyloristrains were resistant to clarithromycin (primary 19% (8/43), secondary 38% (3/8)). 16% (8/51) of strains were resistant to levofloxacin (primary 12% (5/43), secondary 38% (3/8)).Conclusion. The present study has shown the increasing amount of resistantH. pyloristrains isolated from patients in Southern Poland to levofloxacin and decreasing number of resistant strains to clarithromycin.