Review article: the treatment of refractory Helicobacter pylori infection

Dual-Targeted Graphitic Cascade Nanozymes for Recognition and Treatment of Helicobacter pylori

Helicobacter pylori (H. pylori) is the major etiological factor of a variety of gastric diseases. However, the treatment of H. pylori is challenged by the destruction of targeted drugs by gastric acid and pepsin. Herein, a dual-targeted cascade catalytic nanozyme PtCo@Graphene@Hemin-2(L-arginine) (PtCo@G@H2A) is designed for the treatment of H. pylori. The dual-targeting ability of PtCo@G@H2A is derived from directly targeting the receptor protein of H. pylori through hemin and responding to the acidic environment to cause charge reversal (protonation of L-arginine) to capture H. pylori, achieving efficient targeting effect. Compared with the single-targeting strategy relying on hemin, the dual-targeting strategy can greatly improve the targeting rate, achieving an increase of 850% targeting rate. At the concentration of NaHCO3 in intestinal fluid, the surface potential of PtCo@G@H2A can be quickly restored to avoid side effects. Meanwhile, PtCo@G@H2A has pH-responsive oxidase-like activity, which can generate nitric oxide (NO) through a cascade catalytic process that first generates reactive oxygen species (ROS) with oxygen, and further oxidizes L-arginine through ROS, realizing a superior acid-selective bactericidal effect. Overall, it proposes a promising strategy for the treatment of H. pylori that maintains high targeting and therapeutic effects in the environment of gastric acid and pepsin.

Efficacy and safety of vonoprazan-based dual therapy and esomeprazole-based dual therapy in eradicating primary Helicobacter pylori infection: A propensity score matching analysis

BACKGROUND

According to the Maastricht VI/Florence consensus report, potassium-competitive acid blockers (P-CAB) may improve Helicobacter pylori eradication treatment.

MATERIALS AND METHODS

A total of 213 H. pylori treatment-naive patients aged between 18 and 70 years were treated with two regimens. The two regimens are VDT: 20 mg vonoprazan twice a day and 1 g amoxicillin three times daily and EDT: 20 mg esomeprazole four times a day and 750 mg amoxicillin four times daily. 13 C-urea breath tests were used to evaluate eradication rate 4-6 weeks after treatment. Based on propensity score matching (PSM), this retrospective study analyzed the eradication rates, adverse events (AEs), compliance, and antibiotic resistance rates in VDT and EDT groups.

RESULTS

On intention-to-treat (ITT) analysis, the eradication rate in VDT group (89.0%; 95% CI 81.7-96.3) was non-inferior to that in EDT group (87.7%; 95% CI 80.1-95.3; p = 0.796). The corresponding per-protocol (PP) eradication rates were 94.1% (95% CI 88.4-99.8) and 92.8% (95% CI 86.7-98.9; p = 1.000), respectively. There were no significant between-group differences with respect to compliance or incidence of AEs.

CONCLUSIONS

The efficacy and safety of 14-day VDT and EDT were comparable. Therefore, 14-day VDT or EDT may be recommended for the first-line treatment of H. pylori infection.

Eradication rates of Helicobacter pylori in treatment-naive patients following 14-day vonoprazan-amoxicillin dual therapy: A multicenter randomized controlled trial in China

BACKGROUND

Potassium-competitive acid blockers (P-CAB) are recommended for the treatment of Helicobacter pylori infections, but dual therapy of P-CAB with amoxicillin has been poorly studied. The current study compared the efficacy, adverse reactions, compliance, and effects on gut microbiota of 14-day vonoprazan-amoxicillin (VA) dual therapy with esomeprazole, bismuth potassium citrate, amoxicillin, and metronidazole (EBAM) quadruple therapy in treatment-naive patients with H. pylori.

MATERIALS AND METHODS

This was a multicenter, open-label, randomized, and controlled, non-inferiority study. Patients (n = 194) enrolled from six centers were randomly divided into either the VA or EBAM group. H. pylori eradication was determined using ¹³ C urea breath tests (UBT) 4-6 weeks post-treatment. Fecal samples were collected, and gut microbial populations were analyzed by 16S rDNA and metagenomic sequencing technology.

RESULTS

Eradication rates of H. pylori in the VA and EBAM groups were 88.7% and 91.8%, respectively, according to intention-to-treat (ITT) analysis; 95.6% and 96.7% with per-protocol (PP) analysis; and 94.5% and 96.7% with modified ITT (mITT) analysis (all p > 0.05). The incidence of adverse reactions in the VA group was significantly lower compared to the EBAM group, and compliance within both groups was good. There was no difference in α-diversity or microbial composition in the VA and EBAM groups at one-month post-treatment compared to baseline, except for a markedly reduced abundance of Bacteroides in the EBAM group.

CONCLUSION

VA therapy achieved excellent eradication rates with low adverse reactions, good compliance, and little impact on gut microbiota. VA therapy should be recommended as a first-line treatment against H. pylori.

Gastric Acid-Responsive ROS Nanogenerators for Effective Treatment of Helicobacter pylori Infection without Disrupting Homeostasis of Intestinal Flora

Helicobacter pylori (H. pylori) has infected more than half of the world's population, and is the major cause of gastric cancer. The efficacy of standard antibiotic-based triple therapy is declining due to drug resistance development. Herein, a pH-responsive reactive oxygen species (ROS) nanogenerator (Fe-HMME@DHA@MPN) composed of acid-responsive metal polyphenol network (MPN) shell and mesoporous metal-organic nanostructure core [Fe-HMME (hematoporphyrin monomethyl ether, sonosensitizer)] loaded with dihydroartemisinin (DHA) is reported. These nanoparticles generate more ROS singlet oxygen than sonosensitizer HMME under ultrasonication, and this sonodynamic process is fueled by oxygen generated through Fenton/Fenton-like reactions of the degraded product in gastric acid Fe (II) and hydrogen peroxide (H₂ O₂ ) in the infection microenvironment. The encapsulated DHA, as a hydroperoxide source, is found to enhance the peroxidase-like activity of the Fe-HMME@DHA@MPN to generate ROS hydroxyl radical, beneficial for the microenvironment without sufficient H₂ O₂ . In vitro experiments demonstrate that the ROS nanogenerators are capable of killing multidrug-resistant H. pylori and removing biofilm, and ROS nanogenerators show high therapeutic efficacy in a H. pylori infection mouse model. Unlike the triple therapy, the nanogenerators display negligible side effects toward the normal gut microbiota. Taken together, these self-enhanced ROS nanogenerators have a great potential for treatment of H. pylori infection.

A Malaysian consensus report on the diagnosis and treatment of Helicobacter pylori infection

Helicobacter pylori is one of the most common chronic bacterial infections in humans and responsible for 90% of duodenal ulcers and 70-90% of gastric ulcers. Despite this, many misconceptions regarding the appropriate diagnostic method and treatment strategies still exist in the Malaysian clinical practice. Under the initiative of the steering committee, an expert panel consisting of nine key opinion leaders in the field of gastroenterology convened to develop a set of consensus statements that are relevant to the Malaysian healthcare practice. The panel members reviewed the current evidence on the management of H. pylori infection, focusing on the best practices that are relevant to the Malaysian population based on clinical experience and published clinical evidence. Using the modified Delphi method, the panel achieved consensus in three areas of H. pylori infection management: indications for testing, diagnosis, and treatment. The panel proposed a set of 19 consensus statements, which were synthesized via two rounds of blinded voting and group discussions. The recommendations provided are relevant to the Malaysian population and can be used as a guide by physicians across various healthcare settings to facilitate appropriate diagnostic testing and treatment of H. pylori infection.

Rifabutin as salvage therapy for Helicobacter pylori eradication: Cornerstones and novelties

When several Helicobacter pylori eradication treatments fail, guidelines recommend a cultured guided approach; however, culture is not widely available. Therefore, a rifabutin based regimen could be the best solution. Rifabutin indeed shows a low rate of antibiotic resistance. Rifabutin is generally used in combination with amoxicillin in a triple therapy, with eradication rates about 80% in third-line regimens. The ideal duration of this therapy should range between 10 and 12 d. Combinations with antibiotics other than amoxicillin have demonstrated even better results, such as vonoprazan, which is a type of novel acid suppressor drug. Finally, a new formulation of triple therapy in a single capsule is under investigation, which is a field that deserves further investigation. Some notes of caution about rifabutin should be mentioned. This drug is used to treat tuberculosis or atypical mycobacteria; therefore, before starting a rifabutin-based eradication regimen, Mycobacterium tuberculosis infection should be thoroughly tested, since its use could promote the development of antibiotic resistance, thus affecting its effectiveness against Koch’s bacillus. Additionally, some serious side effects must be evaluated before starting any rifabutin-based therapy. Adverse effects include fever, nausea, vomiting and bone marrow suppression. For this reason, full blood count surveillance is required.

Helicobacter pylori Antibiotic Resistance in the United States Between 2011 and 2021: A Systematic Review and Meta-Analysis

INTRODUCTION

Antimicrobial resistance among Helicobacter pylori strains has been rising globally, leading to declining eradication rates. We performed a systematic review and meta-analysis of the resistance patterns of H. pylori strains in the United States between 2011 and 2021.

METHODS

Ovid MEDLINE, Embase, CINAHL, and Cochrane CENTRAL databases were searched for manuscripts and conference abstracts published between 2011 and 2021 reporting H. pylori antibiotic resistance. A mixed-effects model estimated pooled rates of resistance to clarithromycin, amoxicillin, metronidazole, tetracycline, rifabutin, levofloxacin, or a combination of these, with 95% confidence intervals (CIs).

RESULTS

A total of 19 studies including 2,660 samples, met inclusion criteria. The pooled rate of resistance to metronidazole was 42.1% (95% CI 27.3%-58.6%), levofloxacin 37.6% (95% CI 26.3%-50.4%), clarithromycin 31.5% (95% CI 23.6%-40.6%), amoxicillin 2.6% (95% CI 1.4%-5.0%), tetracycline 0.87% (95% CI 0.2%-3.8%), rifabutin 0.17% (95% CI 0.00%-10.9%), and dual clarithromycin and metronidazole 11.7% (95% CI 0.1%-94.0%). Considerable data heterogeneity was evident for pooled resistance prevalence rates (I 2 > 50%), with the exception of rifabutin resistance.

DISCUSSION

Metronidazole, levofloxacin, and clarithromycin resistance rates each exceed 30%; thus, choosing an empiric antibiotic regimen without knowledge of the likely pattern of antibiotic resistance is not appropriate. Resistance to tetracycline, rifabutin, and amoxicillin remains low. Given the scarcity of available data with considerable heterogeneity among studies, continued surveillance, ideally with a more systematic approach to data collection, is an increasingly important goal in H. pylori management.

Effect of major CYP2C19 genetic polymorphisms on Helicobacter pylori eradication based on different treatment regimens

Helicobacter pylori (H. pylori) infection is a global issue. Its eradication in affected individuals is important to prevent several further complications that may occur if left untreated. Proton pump inhibitors (PPIs) serve an important role in the eradication regimens of H. pylori. PPIs are metabolized primarily through the CYP2C19 enzyme in the liver. Inter-individual variation in the response to eradication treatment may partly be due to variations in the metabolism of PPIs. The aim of this study was to determine whether there was any association between CYP2C19 genetic polymorphisms and the response to eradication therapy amongst Jordanians infected with H. pylori receiving lansoprazole-based regimens. The present study was approved by the Institutional Review Board of The University of Jordan Hospital. A total of 141 patients infected with H. pylori were genotyped for the polymorphisms CYP2C19^*2 and CYP2C19^*17 using the PCR-restriction fragment length polymorphism assay method. Patients received lansoprazole-based triple or sequential therapy. The assessment of eradication was performed using either a H. pylori stool antigen test or from feedback from patients regarding their improvement. Eradication rates were 84.6% and 64.5% in the intermediate-metabolizer and extensive-metabolizer group, respectively. This difference was not statistically significant. Moreover, no significant association was found between the carriers of the CYP2C19^*17 polymorphism and the response to eradication therapy. These findings suggest that there was no significant association between the CYP2C19 genotype and the response to eradication therapy amongst Jordanians infected with H. pylori.

Three-Decade Failure to the Eradication of Refractory Helicobacter pylori Infection and Recent Efforts to Eradicate the Infection

BACKGROUND

Helicobacter pylori causes dangerous and deadly diseases such as gastric cancer and duodenal ulcers. Eradication and treatment of this bacterium are very important due to the deadly diseases caused by H. pylori and the high cost of treatment for countries.

METHODS

Thus, we present a complete list of the most important causes of failure in the treatment and eradication of H. pylori, and address new therapeutic methods that may be effective in controlling this bacterium in the future.

RESULTS

Many efforts have been made to control and eradicate this bacterium over the years, but no success has been achieved since its eradication is a complex process affected by the bacterial properties and host factors. Previous studies have shown that various factors are involved in the failure to eradicate H. pylori, such as new genotypes of the bacterium with higher pathogenicity, inappropriate patient cooperation, mutations, biofilm formation and dormant forms that cause antibiotic resistance, acidic stomach pH, high bacterial load, smoking, immunosuppressive features and intracellular occurrence of H. pylori. On the other hand, recent studies reported that the use of probiotics, nanoparticles, antimicrobial peptides, natural product and vaccines can be helpful in the treatment and eradication of H. pylori infections.

CONCLUSION

Eradication of H. pylori is crucial for the treatment of important diseases such as gastric cancer. Therefore, it seems that identifying the failure causes of treating this bacterium can be helpful in controlling the infections. Besides, further studies on new therapeutic strategies may help eradicate H. pylori in the future.

Identification of hub genes and signaling pathways related to gastric cells infected by Helicobacter pylori

BACKGROUND

Helicobacter pylori is a pathogen involved in several gastroduodenal diseases, whose infection mechanisms have not been completely confirmed. To study the specific mechanism of gastropathy caused by H. pylori, we analyzed the gene microarray of gastric mucosa and gastric cells infected by H. pylori through bioinformatics analysis.

METHODS

We downloaded GSE60427 and GSE74492 from the Gene Expression Omnibus (GEO) database, screened differentially expressed genes (DEGs), and identified the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) through R software. The Search Tool for the Retrieval of Interacting Genes (STRING) was applied to establish a protein-protein interaction (PPI) network and Cytoscape was used to identify the top seven hub genes. Besides, we also constructed the gene-microRNA(gene-miRNA) interaction through the miRTarBase v8.0 database by using the NetworkAnalyst tool.

RESULTS

One hundred and fifteen DEGs were screened out, with 54 genes up-regulated and 61 genes down-regulated, among which seven hub genes, including "IGF1R," "APOE," "IRS1," "ATF3," "LCN2," "IL2RG," and "PI3," were considered as the main regulatory proteins in gastric cells when infected by H. pylori.

CONCLUSION

In this study, hub genes and related signal enrichment pathways of gastropathy infected by H. pylori were analyzed through bioinformatics analysis based on the GSE60427 and GSE74492 datasets.

In vivo activation of pH-responsive oxidase-like graphitic nanozymes for selective killing of Helicobacter pylori

Helicobacter pylori infection is a major etiological factor in gastric diseases. However, clinical antibiotic therapy for H. pylori is limited by continuously decreased therapeutic efficacy and side effects to symbiotic bacteria. Herein, we develop an in vivo activatable pH-responsive graphitic nanozyme, PtCo@Graphene (PtCo@G), for selective treatment of H. pylori. Such nanozymes can resist gastric acid corrosion, exhibit oxidase-like activity to stably generate reactive oxygen species only in acidic gastric milieu and demonstrate superior selective bactericidal property. C₁₈-PEG_n-Benzeneboronic acid molecules are modified on PtCo@G, improving its targeting capability. Under acidic gastric pH, graphitic nanozymes show notable bactericidal activity toward H. pylori, while no bacterial killing is observed under intestinal conditions. In mouse model, high antibacterial capability toward H. pylori and negligible side effects toward normal tissues and symbiotic bacteria are achieved. Graphitic nanozyme displays the desired enzyme-like activities at corresponding physiological sites and may address critical issues in clinical treatment of H. pylori infections.

Helicobacter pylori is a major cause of gastric diseases, but the standard therapy is limited by continuously decreased therapeutic efficacy and side effects to symbiotic bacteria. Here, the authors develop a pH-responsive graphitic nanozyme that is active under low pH gastric conditions, but inactive in intestines, for selective treatment of H. pylori infections.

Chilean Rhubarb, Gunnera tinctoria (Molina) Mirb. (Gunneraceae): UHPLC-ESI-Orbitrap-MS Profiling of Aqueous Extract and its Anti-Helicobacter pylori Activity

The full UHPLC-MS metabolome fingerprinting and anti-Helicobacter pylori effect of Gunnera tinctoria (Molina) Mirb. (Nalca) total extract (GTE) and fractions prepared from its edible fresh petioles were evaluated. The activity of G. tinctoria against H. pylori strains ATCC 45504 and J99 was assessed in vitro by means of agar diffusion assay, Minimum Inhibition Concentration (MIC), and Minimum Bactericidal Concentration (MBC), while killing curve and transmission electronic microscopy (TEM) were conducted in order to determine the effect of the plant extract on bacterial growth and ultrastructure. Additionally, the inhibitory effect upon urease was evaluated using both the Jack Bean and H. pylori enzymes. To determine which molecules could be responsible for the antibacterial effects, tentative identification was done by ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-Q-Orbitrap®-HR-MS). Furthermore, the total G. tinctoria extract was fractionated using centrifugal partition chromatography (CPC), giving four active fractions (1-4). It was determined that the crude extract and centrifugal partition chromatography fractions of G. tinctoria have a bactericidal effect being the lowest MIC and MBC = 32 μg/ml. In the killing curves, fraction one acts faster than control amoxicillin. In the urease assay, F3 exhibited the lowest IC50 value of 13.5 μg/ml. Transmission electronic microscopy showed that crude G. tinctoria extract promotes disruption and separation of the cellular wall and outer membrane detachment on H. pylori causing bacterial cell death.

Rifabutin for the Treatment of Helicobacter Pylori Infection: A Review

Nowadays, apart from having to know first-line Helicobacter pylori eradication regimens well, we must also be prepared to face treatment failures. The aim of this review is to summarize the role of rifabutin in the management of H. pylori infection. Bibliographical searches were performed in PubMed. Data on resistance and efficacy of rifabutin-containing regimens on H. pylori eradication were meta-analyzed. Mean H. pylori rifabutin resistance rate (39 studies, including 9721 patients) was 0.13%; when studies only including patients naïve to H. pylori eradication treatment were considered, this figure was even lower (0.07%). Mean H. pylori eradication rate (by intention-to-treat) with rifabutin-containing regimens (3052 patients) was 73%. Respective cure rates for second-, third-, fourth- and fifth-line therapies, were 79%, 69%, 69% and 72%. Most studies administered rifabutin 300 mg/day, which seemed to be more effective than 150 mg/day. The ideal length of treatment remains unclear, but 10–12-day regimens are generally recommended. Adverse events to rifabutin treatment in H. pylori studies were relatively infrequent (15%), and severe adverse events were exceptional (myelotoxicity was the most significant, although always reversible). In summary, rifabutin-containing therapy represents an encouraging strategy generally restricted, at present, to patients where previous (usually multiple) eradication regimens have failed.

Synthesis and Biological Evaluation of Carvacrol-Based Derivatives as Dual Inhibitors of H. pylori Strains and AGS Cell Proliferation

This study reports on the synthesis, structural assessment, microbiological screening against several strains of H. pylori and antiproliferative activity against human gastric adenocarcinoma (AGS) cells of a large series of carvacrol-based compounds. Structural analyses consisted of elemental analysis, 1H/13C/19F NMR spectra and crystallographic studies. The structure-activity relationships evidenced that among ether derivatives the substitution with specific electron-withdrawing groups (CF3 and NO2) especially in the para position of the benzyl ring led to an improvement of the antimicrobial activity, whereas electron-donating groups on the benzyl ring and ethereal alkyl chains were not tolerated with respect to the parent compound (MIC/MBC = 64/64 µg/mL). Ester derivatives (coumarin-carvacrol hybrids) displayed a slight enhancement of the inhibitory activity up to MIC values of 8-16 µg/mL. The most interesting compounds exhibiting the lowest MIC/MBC activity against H. pylori (among others, compounds 16 and 39 endowed with MIC/MBC values ranging between 2/2 to 32/32 µg/mL against all the evaluated strains) were also assayed for their ability to reduce AGS cell growth with respect to 5-Fluorouracil. Some derivatives can be regarded as new lead compounds able to reduce H. pylori growth and to counteract the proliferation of AGS cells, both contributing to the occurrence of gastric cancer.

Rescue therapy with rifabutin regimen for refractory Helicobacter pylori infection with dual drug-resistant strains

Background

There is no current standard rescue treatment for dual drug-resistant strains of Helicobacter pylori (H. pylori). This aim of this study was to investigate the efficacy of rifabutin-based triple therapy for patients infected with dual drug-resistant strains to clarithromycin and levofloxacin.

Methods

After 2 or 3 H. pylori treatment failures, patients underwent upper endoscopy with tissue biopsies. Phenotypic and genotypic resistances were determined using agar dilution test and polymerase chain reaction with direct sequencing, respectively. Patients infected with dual drug-resistant (clarithromycin and levofloxacin) strains and receiving rifabutin-based triple therapy (rifabutin 150 mg bid, amoxicillin 1 g bid and esomeprazole 40 mg bid for 10 days) were enrolled. Eradication status was determined by 13C-urea breath test 4 weeks after treatment completion.

Results

A total of 39 patients infected with dual drug-resistant strains were enrolled in this study, with a mean age of 55.9 years. The eradication rate was 79.5% (31/39) (95% confidence intervals: 54.96% ~ 111.40%). Adverse event was reported in 23.1% (9/39) of patients but they were mild and tolerable. In univariate analysis, no factor was identified as an independent predictor of eradication failure.

Conclusions

Our current study demonstrated that rifabutin-based triple therapy was well tolerated and yielded an acceptable eradication rate for patients infected with dual drug-resistant strains of H. pylori.

Passive Ceiling Light Disinfection System to Reduce Bioburden in an Intensive Care Unit

A ceiling-installed narrow spectrum (402-420 nm) bactericidal blue light disinfection system was installed in a large suburban medical intensive care unit (ICU) and evaluated for implementation feasibility and effectiveness in reducing environmental bioburden. Installation of 54 ceiling devices was accomplished at low cost and with minimal ICU process disruption. Postinstallation high-touch surface colony counts were significantly lower than preinstallation. Linear mixed modeling demonstrated a 21% average overall decrease in colony count after installation, with consistent reduction in colony counts starting from week 4 postinstallation. Automated technology is potentially more efficient in reducing environmental bioburden in the acute care setting compared with other bioburden reducing methods or can provide a robust compliment to manual cleaning.

Antibacterial activity of ovatodiolide isolated from Anisomeles indica against Helicobacter pylori

Helicobacter pylori infection is associated with high incidence of gastric diseases. The extensive therapy of H. pylori infection with antibiotics has increased its resistance rates worldwide. Ovatodiolide, a pure constituent isolated from Anisomeles indica, has been demonstrated to possess bactericidal activity against H. pylori. In this study, ovatodiolide inhibited the growth of both H. pylori reference strain and clinical multidrug-resistant isolates. Docking analysis revealed that ovatodiolide fits into the hydrophobic pocket of a ribosomal protein, RpsB. Furthermore, ovatodiolide inhibited bacterial growth by reducing levels of RpsB, which plays a crucial role in protein translation. Our results demonstrate that ovatodiolide binds to a ribosomal protein and interferes with protein synthesis. This study provides evidence that ovatodiolide has the potential to be developed into a potent therapeutic agent for treating H. pylori infection.

Herbal medicine as an auspicious therapeutic approach for the eradication of Helicobacter pylori infection: A concise review

Helicobacter pylori (H. pylori) causes gastric mucosa inflammation and gastric cancer mostly via several virulence factors. Induction of proinflammatory pathways plays a crucial role in chronic inflammation, gastric carcinoma, and H. pylori pathogenesis. Herbal medicines (HMs) are nontoxic, inexpensive, and mostly anti-inflammatory reminding meticulous emphasis on the elimination of H. pylori and gastric cancer. Several HM has exerted paramount anti-H. pylori traits. In addition, they exert anti-inflammatory effects through several cellular circuits such as inhibition of 5'-adenosine monophosphate-activated protein kinase, nuclear factor-κB, and activator protein-1 pathway activation leading to the inhibition of proinflammatory cytokines (interleukin 1α [IL-1α], IL-1β, IL-6, IL-8, IL-12, interferon γ, and tumor necrosis factor-α) expression. Furthermore, they inhibit nitrous oxide release and COX-2 and iNOS activity. The apoptosis induction in Th1 and Th17-polarized lymphocytes and M2-macrophagic polarization and STAT6 activation has also been exhibited. Thus, their exact consumable amount has not been revealed, and clinical trials are needed to achieve optimal concentration and their pharmacokinetics. In the aspect of bioavailability, solubility, absorption, and metabolism of herbal compounds, nanocarriers such as poly lactideco-glycolide-based loading and related formulations are helpful. Noticeably, combined therapies accompanied by probiotics can also be examined for better clearance of gastric mucosa. In addition, downregulation of inflammatory microRNAs (miRNAs) by HMs and upregulation of those anti-inflammatory miRNAs is proposed to protect the gastric mucosa. Thus there is anticipation that in near future HM-based formulations and proper delivery systems are possibly applicable against gastric cancer or other ailments because of H. pylori.

Can light-based approaches overcome antimicrobial resistance?

The relentless rise of antibiotic resistance is considered one of the most serious problems facing mankind. This mini-review will cover three cutting-edge approaches that use light-based techniques to kill antibiotic-resistant microbial species, and treat localized infections. First, we will discuss antimicrobial photodynamic inactivation using rationally designed photosensitizes combined with visible light, with the added possibility of strong potentiation by inorganic salts such as potassium iodide. Second, the use of blue and violet light alone that activates endogenous photoactive porphyrins within the microbial cells. Third, it is used for "safe UVC" at wavelengths between 200 nm and 230 nm that can kill microbial cells without damaging host mammalian cells. We have gained evidence that all these approaches can kill multidrug resistant bacteria in vitro, and they do not induce themselves any resistance, and moreover can treat animal models of localized infections caused by resistant species that can be monitored by noninvasive bioluminescence imaging. Light-based antimicrobial approaches are becoming a growing translational part of anti-infective treatments in the current age of resistance.

Probiotic Lactobacillus spp. act Against Helicobacter pylori-induced Inflammation

The bacterial species, Helicobacter pylori, is associated with several gastrointestinal diseases, and poses serious health threats owing to its resistance to antibiotics. Lactobacillus spp., on the other hand, possess probiotic activities that have beneficial effects in humans. However, the mechanisms by which Lactobacillus spp. harbor favorable functions and act against H. pylori infection remain to be explored. The aim of this study was to investigate the ability of bacterial strains, Lactobacillus rhamnosus and Lactobacillus acidophilus, termed GMNL-74 and GMNL-185, respectively, to inhibit H. pylori growth and inflammation. Our results showed that GMNL-74 and GMNL-185 possess potent antimicrobial activity against multidrug resistant (MDR)-H. pylori. In addition, an in vitro cell-based model revealed that the inhibition of H. pylori adhesion and invasion of gastric epithelial cells and interleukin-8 production were significantly decreased by treatment with both the Lactobacillus strains. In vivo studies demonstrated that colonization of H. pylori and induced inflammation in the mouse stomach were also alleviated by these Lactobacillus strains. Furthermore, the abundance of beneficial gut bacteria, including Bifidobacterium spp. and Akkermansia muciniphilia, were significantly increased in H. pylori-infected mice treated with GMNL-74 and GMNL-185. These results demonstrate that Lactobacillus spp. ameliorate H. pylori-induced inflammation and supports beneficial gut specific bacteria that act against H. pylori infection.

Effective antimicrobial activity of rifabutin against multidrug-resistant Helicobacter pylori

BACKGROUND

Helicobacter pylori resistance to more than one antibiotic is the main reason for failure in bacterial eradication in a considerable number of patients. Rifabutin (RFB) with a broad-spectrum of antimicrobial therapy has been suggested for treatment of refractory multidrug-resistant infections.

METHODS

Helicobacter pylori isolates from 104 patients were examined for resistance to 5 currently used antibiotics and RFB, using agar dilution method. Twofold serial dilutions of antibiotics were used and MICs (μg/mL) determined as metronidazole (MTZ 8), clarithromycin (CLR 2), amoxicillin (AMX 1), tetracycline (TET 0.5), furazolidone (FRZ 0.5), and RFB (0.06).

RESULTS

Of 104 H. pylori isolates, only 7 (6.7%) were sensitive to all the 6 antibiotics. However, 30 (28.8%) were resistant to one antibiotic, 28 (26.9%) to two, 19 (18.2%) to three, 14 (13.4%) to four, and 6 (5.7%) to five currently used antibiotics. Overall, 67(64.4%) of isolates were resistant to 2-5 currently used antibiotics and considered as multidrug-resistant (MDR), with 59 (88.1%) showing sensitivity to RFB and 8 (11.9%) resistance (P < 0.05). Of 33 isolates resistant to both MTZ and CLR, 25 (75.7%) were sensitive to RFB and 8 (24.3%) resistant (P < 0.05).

DISCUSSION

In vitro antimicrobial effectiveness of RFB on MDR H. pylori including those with resistance to both MTZ and CLR was demonstrated. However, RFB efficacy decreased as the number of antibiotics responsible for MDR increased. Considering that RFB inhibits both extra- and intracellular H. pylori, it can be suggested as an effective antibiotic against of MDR H. pylori.

Phenotypic analysis of antibiotic resistance and genotypic study of the vacA, cagA, iceA, oipA and babA genotypes of the Helicobacter pylori strains isolated from raw milk

Background

Foods with animal origins and particularly milk play a considerable role in transmission of Helicobacter pylori. The current study was performed to assess phenotypic characters of antibiotic resistance and genotyping pattern of vacA, cagA, iceA, oipA and babA2 alleles amongst the H. pylori strains isolated from raw milk.

Methods

Six-hundred and thirty raw milk samples were collected and cultured on Wilkins Chalgren anaerobe media. Antibiotic resistance and genotyping patterns were studied using disk diffusion and PCR, respectively.

Results

Sixty-seven out of 630 (10.63%) raw milk samples were positive for H. pylori. Ovine raw milk (17.27%) samples had the highest prevalence of H. pylori, while camel (5.00%) had the lowest. H. pylori strains harbored the highest prevalence of resistance against ampicillin (82.08%), tetracycline (76.11%), amoxicillin (74.62%), metronidazole (65.67%) and erythromycin (53.73%). Prevalence of resistance against more than 10 types of antibiotics was 17.91%. VacA s1a (83.58%), m1a (80.59%), s2 (77.61%) and m2 (68.65%), cagA (73.13%) and babA2 (44.77%) were the most commonly detected genotypes. We found that S1am1a (56.71%), s2m1a (56.71%), s1 am2 (43.28%) and s2 m2 (43.28%) were the most commonly detected genotyping pattern. Frequency of cagA-, oipA- and babA2- genotypes were 26.86%, 62.68% and 55.22%, respectively. We found that S1a/cagA+/iceA1/oipA-/babA2- (28.35%), m1a/cagA+/iceA1/oipA-/babA2- (28.35%) and s2/cagA+/iceA1/oipA-/babA2- (26.86%) were the most commonly detected combined genotyping pattern.

Conclusions

Simultaneous presence of vacA, cagA, iceA, oipA and babA2 genotypes in antibiotic resistant H. pylori strains indicates important public health issue regarding the consumption of raw milk. However, additional researches are required to find molecular genetic homology and other epidemiological aspects of H. pylori in milk.

Selective killing of Helicobacter pylori with pH-responsive helix-coil conformation transitionable antimicrobial polypeptides

Current clinical treatment of Helicobacter pylori infection, the main etiological factor in the development of gastritis, gastric ulcers, and gastric carcinoma, requires a combination of at least two antibiotics and one proton pump inhibitor. However, such triple therapy suffers from progressively decreased therapeutic efficacy due to the drug resistance and undesired killing of the commensal bacteria due to poor selectivity. Here, we report the development of antimicrobial polypeptide-based monotherapy, which can specifically kill H. pylori under acidic pH in the stomach while inducing minimal toxicity to commensal bacteria under physiological pH. Specifically, we designed a class of pH-sensitive, helix-coil conformation transitionable antimicrobial polypeptides (HCT-AMPs) (PGA)m-r-(PHLG-MHH)n, bearing randomly distributed negatively charged glutamic acid and positively charged poly(γ-6-N-(methyldihexylammonium)hexyl-l-glutamate) (PHLG-MHH) residues. The HCT-AMPs showed unappreciable toxicity at physiological pH when they adopted random coiled conformation. Under acidic condition in the stomach, they transformed to the helical structure and exhibited potent antibacterial activity against H. pylori, including clinically isolated drug-resistant strains. After oral gavage, the HCT-AMPs afforded comparable H. pylori killing efficacy to the triple-therapy approach while inducing minimal toxicity against normal tissues and commensal bacteria, in comparison with the remarkable killing of commensal bacteria by 65% and 86% in the ileal contents and feces, respectively, following triple therapy. This strategy renders an effective approach to specifically target and kill H. pylori in the stomach while not harming the commensal bacteria/normal tissues.

Optimization strategies aimed to increase the efficacy of H. pylori eradication therapies

BACKGROUND

As with any other infectious disease, we should aim for treatments offering ≥90% Helicobacter pylori eradication rates in clinical practice.

AIM

To summarize optimization strategies aimed to increase the efficacy of H. pylori eradication therapies.

METHODS

A systematic bibliographic search (in PubMed up to August 2016) was designed to identify studies investigating optimization strategies aimed to increase the efficacy of H. pylori eradication therapies.

RESULTS

The most direct way to optimize a treatment is using higher doses of drugs unless it has been shown that lower doses are equally effective. Similarly, prescriptions should use 14-day duration unless a shorter scheme has been shown locally to be equally effective. Double-dose proton-pump inhibitor therapy is recommended for triple therapy and may probably increase the efficacy of nonbismuth concomitant regimen as well. The efficacy of triple therapies in the presence of resistance can be significantly improved by the addition of bismuth salts, which offer an additive effect in combination with antibiotics. Overall, probiotics seem to reduce antibiotic side effects, but the increase in eradication rates is not so evident; therefore, they cannot be generally recommended for clinical practice yet.

CONCLUSIONS

Using potent acid inhibition and/or higher antibiotic doses-especially by increasing the number of daily intakes-and lengthening treatments up to 14 days improves efficacy in most regimens and should be generally recommended. Triple therapies can be efficiently improved by the addition of bismuth salts, turning them into quadruple therapies. Finally, some treatments will require a combination of optimization strategies to significantly improve results.

[Frequency of Helicobacter pylori nitroreductase RdxA mutations for metronidazole activation in a population in the Cauca Department, Colombia]

INTRODUCTION

Resistance to metronidazole is a key factor associated with Helicobacter pylori treatment failure. Even though resistance is mostly associated with RdxA nitroreductase mutations, studies of this H. pylori protein in Popayán (Colombia) are still incipient.

OBJECTIVE

To evaluate the frequency of mutations in the RdxA nitroreductase in a population of patients with H. pylori-positive gastrointestinal disease.

MATERIALS AND METHODS

We amplified the DNA of 170 gastric biopsies by PCR to detect mutations in the RdxA nitroreductase. An analysis of DNA sequences translated into amino acid sequences was done and then compared to the reference strain 26695.

RESULTS

The frequency of RdxA nitroreductase mutations in this study population was 78%. Its most frequent distribution was found in positions D59N (153 samples), R131K (101 samples), R90K (97 samples), A118T (42 samples), I160F (32 samples) and H97T (26 samples), and meaningful stop codons Q50*, D59*; E75*, C159* and I160* in five, one, three, ten and six samples, respectively. The most common virulence genotype was vacAs1/m1 cagA negative (48.6 %).

CONCLUSIONS

The high frequency of RdxA nitroreductase mutations in H. pylori isolates in Popayán (Colombia) indicates that empirical therapy with metronidazole may not be a valid option for the eradication of H. pylori in patients of the studied population.

Detection of Helicobacter pylori resistance to clarithromycin and fluoroquinolones in Brazil: A national survey

AIM

To evaluate bacterial resistance to clarithromycin and fluoroquinolones in Brazil using molecular methods.

METHODS

The primary antibiotic resistance rates of Helicobacter pylori (H. pylori) were determined from November 2012 to March 2015 in the Southern, South-Eastern, Northern, North-Eastern, and Central-Western regions of Brazil. Four hundred ninety H. pylori patients [66% female, mean age 43 years (range: 18-79)] who had never been previously treated for this infection were enrolled. All patients underwent gastroscopy with antrum and corpus biopsies and molecular testing using GenoType HelicoDR (Hain Life Science, Germany). This test was performed to detect the presence of H. pylori and to identify point mutations in the genes responsible for clarithromycin and fluoroquinolone resistance. The molecular procedure was divided into three steps: DNA extraction from the biopsies, multiplex amplification, and reverse hybridization.

RESULTS

Clarithromycin resistance was found in 83 (16.9%) patients, and fluoroquinolone resistance was found in 66 (13.5%) patients. There was no statistical difference in resistance to either clarithromycin or fluoroquinolones (P = 0.55 and P = 0.06, respectively) among the different regions of Brazil. Dual resistance to clarithromycin and fluoroquinolones was found in 4.3% (21/490) of patients. The A2147G mutation was present in 90.4% (75/83), A2146G in 16.9% (14/83) and A2146C in 3.6% (3/83) of clarithromycin-resistant patients. In 10.8% (9/83) of clarithromycin-resistant samples, more than 01 mutation in the 23S rRNA gene was noticed. In fluoroquinolone-resistant samples, 37.9% (25/66) showed mutations not specified by the GenoType HelicoDR test. D91N mutation was observed in 34.8% (23/66), D91G in 18.1% (12/66), N87K in 16.6% (11/66) and D91Y in 13.6% (9/66) of cases. Among fluoroquinolone-resistant samples, 37.9% (25/66) showed mutations not specified by the GenoType HelicoDR test.

CONCLUSION

The H. pylori clarithromycin resistance rate in Brazil is at the borderline (15%-20%) for applying the standard triple therapy. The fluoroquinolone resistance rate (13.5%) is equally concerning.

Eradication of Helicobacter pylori Infection

Helicobacter pylori infects about 50 % of the world's population, causing at a minimum chronic gastritis. A subset of infected patients will ultimately develop gastric or duodenal ulcer disease, gastric adenocarcinoma, or MALT (mucosa-associated lymphoid tissue) lymphoma. Eradication of H. pylori requires complex regimens that include acid suppression and multiple antibiotics. The efficacy of treatment using what were once considered standard regimens have declined in recent years, mainly due to widespread development of antibiotic resistance. Addition of bismuth to standard triple therapy regimens, use of alternate antibiotics, or development of alternative regimens using known therapies in novel combinations have improved treatment efficacy in specific populations, but overall success of eradication remains less than ideal. Novel regimens under investigation either in vivo or in vitro, involving increased acid suppression ideally with fewer antibiotics or development of non-antibiotic treatment targets, show promise for future therapy.

Failed Eradication for Helicobacter pylori. What Should Be Done?

Failed eradication of Helicobacter pylori occurs when the antibiotic concentration at the site where H. pylori is located is lower than the minimal inhibitory concentration of the antibiotic for this bacterium. The main reason for this is the acquisition of resistance; and in the context of the most common treatment, the main reason is the acquisition of resistance to clarithromycin. Several options can then be followed. The most rational option is to use a tailored therapy, that is, to look for clarithromycin resistance either by culture plus antibiogram or by a molecular method. The standard triple therapy is used only in the case of clarithromycin susceptibility. In case of resistance or if an empiric treatment must be given, a good option is to use a bismuth-based quadruple therapy. If unavailable, clarithromycin-based quadruple therapies can be used either as sequential or 'concomitant' or hybrid. The limit, especially for concomitant therapy, is the use of clarithromycin, which will be inactive in about 2/3 of the cases, adding to cost and adverse events. Recently, the dual therapy proton pump inhibitor-amoxicillin has been revisited especially in the Far East, and increasing the dose and the frequency of administration gives excellent results.

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.

Detection of clarithromycin-resistant Helicobacter pylori in clinical specimens by molecular methods: A review

Various molecular methods have been developed to rapidly detect clarithromycin (CLR) resistance in Helicobacter pylori isolates in clinical specimens. All of these assays for detecting CLR resistance in H. pylori are based on detection of mutations in the 23S rRNA gene. In this article, we summarise current knowledge regarding the detection of H. pylori CLR resistance in clinical specimens by molecular tests. The available data showed that restriction fragment length polymorphism (RFLP), 3'-mismatch PCR, DNA sequencing, the PCR line probe assay (PCR-LiPA) and fluorescence in situ hybridisation assay (FISH) are able to detect CLR-resistant H. pylori in clinical specimens with excellent specificity and sensitivity. However, several factors limit their clinical application, including fastidious, time-consuming preparation and low-throughput as well as carrying a risk of contamination. Furthermore, as an invasive method, FISH is not suitable for children or the elderly. Among the molecular methods, one that is most promising for the future is real-time PCR probe hybridisation technology using fluorescence resonance energy transfer (FRET) probes, which can rapidly detect CLR resistance with high sensitivity and specificity in biopsies and stool specimens, even though mixed infections are present in clinical specimens. Moreover, due to the advantages that this method is simple, rapid and economical, real-time PCR is technically feasible for clinical application in small- and medium-sized hospitals in developing countries. Second, with high sensitivity, specificity and throughput, DNA chips will also be a valuable tool for detecting resistant H. pylori isolates from cultures and clinical specimens.

Molecular Approaches to Identify Helicobacter pylori Antimicrobial Resistance

Antimicrobial susceptibility testing is needed to adapt Helicobacter pylori treatment to obtain the best results. Beside the standard phenotypic methods, molecular methods are increasingly used. The value of these molecular tests is that they are quick, independent of the transport conditions, easy to standardize, and commercial kits are available. In this article, these methods are reviewed, focusing on the determination of H pylori resistance to macrolides and fluoroquinolones, and mentioning also the methods used for tetracycline and rifampin.

Omega-3 Polyunsaturated Fatty Acids Intake to Regulate Helicobacter pylori-Associated Gastric Diseases as Nonantimicrobial Dietary Approach

Omega-3 polyunsaturated fatty acids (n-3 PUFAs), commonly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been acknowledged as essential long-chain fatty acids imposing either optimal health promotion or the rescuing from chronic inflammatory diseases such as atherosclerosis, fatty liver, and various inflammatory gastrointestinal diseases. Recent studies dealing with EPA and DHA have sparked highest interests because detailed molecular mechanisms had been documented with the identification of its receptor, G protein coupled receptor, and GPR120. In this review article, we have described clear evidences showing that n-3 PUFAs could reduce various Helicobacter pylori- (H. pylori-) associated gastric diseases and extended to play even cancer preventive outcomes including H. pylori-associated gastric cancer by influencing multiple targets, including proliferation, survival, angiogenesis, inflammation, and metastasis. Since our previous studies strongly concluded that nonantimicrobial dietary approach for reducing inflammation, for instance, application of phytoceuticals, probiotics, natural products including Korean red ginseng, and walnut plentiful of n-3 PUFAs, might be prerequisite step for preventing H. pylori-associated gastric cancer as well as facilitating the rejuvenation of precancerous atrophic gastritis, these beneficial lipids can restore or modify inflammation-associated lipid distortion and correction of altered lipid rafts to send right signaling to maintain healthy stomach even after chronic H. pylori infection.

Efficacy of moxifloxacin-based sequential therapy for first-line eradication of Helicobacter pylori infection in gastrointestinal disease

AIM: To evaluate the efficacy of 14-d moxifloxacin-based sequential therapy as first-line eradication treatment of Helicobacter pylori (H. pylori) infection.

METHODS: From December 2013 to August 2014, 161 patients with confirmed H. pylori infection randomly received 14 d of moxifloxacin-based sequential group (MOX-ST group, n = 80) or clarithromycin-based sequential group (CLA-ST group, n = 81) therapy. H. pylori infection was defined on the basis of at least one of the following three tests: a positive ¹³C-urea breath test; histologic evidence of H. pylori by modified Giemsa staining; or a positive rapid urease test (CLOtest; Delta West, Bentley, Australia) by gastric mucosal biopsy. Successful eradication therapy for H. pylori infection was defined as a negative ¹³C-urea breath test four weeks after the end of eradication treatment. Compliance was defined as good when drug intake was at least 85%. H. pylori eradication rates, patient compliance with drug treatment, adverse event rates, and factors influencing the efficacy of eradication therapy were evaluated.

RESULTS: The eradication rates by intention-to-treat analysis were 91.3% (73/80; 95%CI: 86.2%-95.4%) in the MOX-ST group and 71.6% (58/81; 95%CI: 65.8%-77.4%) in the CLA-ST group (P = 0.014). The eradication rates by per-protocol analysis were 93.6% (73/78; 95%CI: 89.1%-98.1%) in the MOX-ST group and 75.3% (58/77; 95%CI: 69.4%-81.8%) in the CLA-ST group (P = 0.022). Compliance was 100% in both groups. The adverse event rates were 12.8% (10/78) and 24.6% (19/77) in the MOX-ST and CLA-ST group, respectively (P = 0.038). Most of the adverse events were mild-to-moderate in intensity; there was none serious enough to cause discontinuation of treatment in either group. In multivariate analysis, advanced age (≥ 60 years) was a significant independent factor related to the eradication failure in the CLA-ST group (adjusted OR = 2.13, 95%CI: 1.97-2.29, P = 0.004), whereas there was no significance in the MOX-ST group.

CONCLUSION: The 14-d moxifloxacin-based sequential therapy is effective. Moreover, it shows excellent patient compliance and safety compared to the 14-d clarithromycin-based sequential therapy.

Complete Genome Sequence of a Metronidazole-Resistant Helicobacter pylori Strain

We report here the complete genome sequence of a metronidazole-resistant Helicobacter pylori strain (MET^r). The MET^r strain was obtained under exposure of H. pylori 26695 on agar plates with low metronidazole concentrations. The genome data provide insight into the genomic changes of H. pylori under selection by metronidazole in vitro.

Search for novel candidate mutations for metronidazole resistance in Helicobacter pylori using next-generation sequencing

Metronidazole resistance is a key factor associated with Helicobacter pylori treatment failure. Although this resistance is mainly associated with mutations in the rdxA and frxA genes, the question of whether metronidazole resistance is caused by the inactivation of frxA alone is still debated. Furthermore, it is unclear whether there are other mutations involved in addition to the two genes that are associated with resistance. A metronidazole-resistant strain was cultured from the metronidazole-susceptible H. pylori strain 26695-1 by exposure to low concentrations of metronidazole. The genome sequences of both susceptible and resistant H. pylori strains were determined by Illumina next-generation sequencing, from which putative candidate resistance mutations were identified. Natural transformation was used to introduce PCR products containing candidate mutations into the susceptible parent strain 26695-1, and the metronidazole MIC was determined for each strain. Mutations in frxA (hp0642), rdxA (hp0954), and rpsU (hp0562) were confirmed by the Sanger method. The mutated sequence in rdxA was successfully transformed into strain 26695-1, and the transformants showed resistance to metronidazole. The transformants containing a single mutation in rdxA showed a low MIC (16 mg/liter), while those containing mutations in both rdxA and frxA showed a higher MIC (48 mg/liter). No transformants containing a single mutation in frxA or rpsU were obtained. Next-generation sequencing was used to identify mutations related to drug resistance. We confirmed that the mutations in rdxA are mainly associated with metronidazole resistance, and mutations in frxA are able to enhance H. pylori resistance only in the presence of rdxA mutations. Moreover, mutations in rpsU may play a role in metronidazole resistance.

Comparison of efficacy and safety of levofloxacin-containing versus standard sequential therapy in eradication of Helicobacter pylori infection in Korea

BACKGROUND

Declining of eradication rates for Helicobacter pylori in Korea may be partly from the increasing prevalence of antibiotic resistance, especially clarithromycin resistance.

AIM

To compare the efficacy and the safety of using 10-day standard sequential therapy and levofloxacin-containing sequential therapy as a first-line treatment for Helicobacter pylori eradication in Korea.

METHODS

A total of 200 patients with proven Helicobacter pylori infection randomly received 10-day standard sequential therapy (n = 100) or levofloxacin-containing sequential therapy (n = 100). The standard sequential therapy group received rabeprazole and amoxicillin for 5 days, followed by rabeprazole, clarithromycin, and metronidazole for 5 more days. The levofloxacin-containing sequential therapy group was treated with rabeprazole and amoxicillin for 5 days, followed by rabeprazole, levofloxacin, and metronidazole for 5 more days.

RESULTS

Intention-to-treat eradication rates were 79.0% and 78.0% for groups of standard sequential and levofloxacin-containing sequential therapy, respectively (P = 0.863). Per-protocol eradication rates were 84.9% and 81.3%, respectively, for these two therapies (P = 0.498). There were no significant differences between the groups in regard to the eradication rates and adverse events.

CONCLUSIONS

The 10-day levofloxacin-containing sequential regimen and the standard sequential regimen showed the similar eradication rates of Helicobacter pylori in Korea.

Centralized isolation of Helicobacter pylori from multiple centers and transport condition influences

AIM: To evaluate the efficacy of centralized culture and possible influencing factors.

METHODS: From January 2010 to July 2012, 66452 patients with suspected Helicobacter pylori (H. pylori) infection from 26 hospitals in Zhejiang and Jiangsu Provinces in China underwent gastrointestinal endoscopy. Gastric mucosal biopsies were taken from the antrum for culture. These biopsies were transported under natural environmental temperature to the central laboratory in Hangzhou city and divided into three groups based on their transport time: 5, 24 and 48 h. The culture results were reported after 72 h and the positive culture rates were analyzed by a χ² test. An additional 5736 biopsies from H. pylori-positive patients (5646 rapid urease test-positive and 90 ¹⁴C-urease breath test-positive) were also cultured for quality control in the central laboratory setting.

RESULTS: The positive culture rate was 31.66% (21036/66452) for the patient samples and 71.72% (4114/5736) for the H. pylori-positive quality control specimens. In the 5 h transport group, the positive culture rate was 30.99% (3865/12471), and 32.84% (14960/45553) in the 24 h transport group. In contrast, the positive culture rate declined significantly in the 48 h transport group (26.25%; P < 0.001). During transportation, the average natural temperature increased from 4.67 to 29.14 °C, while the positive culture rate declined from 36.67% (1462/3987) to 24.12% (1799/7459). When the temperature exceeded 24 °C, the positive culture rate decreased significantly, especially in the 48 h transport group (23.17%).

CONCLUSION: Transportation of specimens within 24 h and below 24 °C is reasonable and acceptable for centralized culture of multicenter H. pylori samples.

Ten day sequential versus 10 day modified bismuth quadruple therapy as empirical firstline and secondline treatment for Helicobacter pylori in Chinese patients: an open label, randomised, crossover trial

OBJECTIVE

Treatments with sequential therapy (SEQ) or bismuth quadruple (QUAD) therapy have been proposed as empirical firstline regimens for Helicobacter pylori. We compared the efficacy and tolerability of 10 day SEQ with 10 day modified QUAD as both firstline and secondline treatments for H pylori in a randomised crossover study.

DESIGN

H pylori positive and treatment naïve patients were randomly assigned to receive either 10 day SEQ (esomeprazole for 10 days, amoxicillin for an initial 5 days, followed by clarithromycin and metronidazole for a subsequent 5 days) or modified QUAD (esomeprazole, bismuth subcitrate, tetracycline and metronidazole). H pylori eradication was confirmed by urea breath test at 8 weeks. Patients who failed the initial assigned treatment were crossed over to receive the alternate regimen. The primary outcome was eradication rates of firstline treatment by intention to treat (ITT) and per protocol (PP) analyses.

RESULTS

357 patients were randomised to receive either SEQ or QUAD. The PP eradication rates of the SEQ and QUAD groups were 95.2% and 98.8%, respectively (p=0.10). Based on ITT analysis, the corresponding eradication rates were 89.4% and 92.7%, respectively (p=0.36). Eight (4.8%) patients in the SEQ and two (1.2%) patients in the QUAD who failed the firstline treatment were crossed over to the alternate regimen with 100% retreatment success. The overall incidence of adverse events was higher in the QUAD (16.7%) than in the SEQ (8.1%; p=0.032) group.

CONCLUSIONS

Ten day sequential and modified bismuth quadruple therapies are both highly effective as empirical firstline therapies for H pylori in Chinese patients.

CLINICALTRIALSGOV

NCT 01760824.

Comparison of standard triple therapy, sequential therapy and moxifloxacin-based triple therapy for Helicobacter pylori infection: Patients' compliance and bacterial eradication rates

OBJECTIVE

To compare the patients' compliance with and the efficacy of existing treatments for Helicobacter pylori eradication, including moxifloxacin-based triple therapy, sequential treatment and the standard treatment.

METHODS

Patients with H. pylori infection were randomly assigned to three therapy groups. The triple therapy (MML) group was given moxifloxacin 400 mg/day, metronidazole 500 mg b.i.d. and lansoprazole 30 mg b.i.d. for 10 days. The sequential treatment (AL-CML) group was administrated amoxicillin 1 g b.i.d. and lansoprazole 30 mg b.i.d. for the first 5 days, followed by clarithromycin 500 mg b.i.d., metronidazole 500 mg b.i.d. and lansoprazole 30 mg b.i.d. for the second 5 days. The standard treatment (CAL) group received amoxicillin 1 g b.i.d., clarithromycin 500 mg b.i.d. and lansoprazole 30 mg b.i.d. for 14 days. The eradication rates were evaluated by per-protocol (PP) analysis and intention-to-treat (ITT) analysis.

RESULTS

The eradication rates were 87.1, 85.9 and 85.2% by PP analysis and 87.1, 84.9 and 84.2% by ITT analysis in the MML, AL-CML and CAL group, respectively, and patients' compliance rates were 98.2, 96.5 and 97.1%, respectively. There were no significant differences in treatment efficacy and compliance rates in the MML, AL-CML and CAL groups (P > 0.05).

CONCLUSIONS

The present study revealed that standard triple therapy, sequential therapy and moxifloxacin-based triple therapy are all effective treatment regimens in terms of H. pylori eradication rates and compliance with therapy in Turkey.

Using informatics and the electronic medical record to describe antimicrobial use in the clinical management of diarrhea cases at 12 companion animal practices

Antimicrobial drugs may be used to treat diarrheal illness in companion animals. It is important to monitor antimicrobial use to better understand trends and patterns in antimicrobial resistance. There is no monitoring of antimicrobial use in companion animals in Canada. To explore how the use of electronic medical records could contribute to the ongoing, systematic collection of antimicrobial use data in companion animals, anonymized electronic medical records were extracted from 12 participating companion animal practices and warehoused at the University of Calgary. We used the pre-diagnostic, clinical features of diarrhea as the case definition in this study. Using text-mining technologies, cases of diarrhea were described by each of the following variables: diagnostic laboratory tests performed, the etiological diagnosis and antimicrobial therapies. The ability of the text miner to accurately describe the cases for each of the variables was evaluated. It could not reliably classify cases in terms of diagnostic tests or etiological diagnosis; a manual review of a random sample of 500 diarrhea cases determined that 88/500 (17.6%) of the target cases underwent diagnostic testing of which 36/88 (40.9%) had an etiological diagnosis. Text mining, compared to a human reviewer, could accurately identify cases that had been treated with antimicrobials with high sensitivity (92%, 95% confidence interval, 88.1%-95.4%) and specificity (85%, 95% confidence interval, 80.2%-89.1%). Overall, 7400/15,928 (46.5%) of pets presenting with diarrhea were treated with antimicrobials. Some temporal trends and patterns of the antimicrobial use are described. The results from this study suggest that informatics and the electronic medical records could be useful for monitoring trends in antimicrobial use.

Discovery of novel mutations for clarithromycin resistance in Helicobacter pylori by using next-generation sequencing

OBJECTIVES

Resistance to clarithromycin is the most important factor causing failure of Helicobacter pylori eradication. Although clarithromycin resistance is mainly associated with three point mutations in the 23S rRNA genes, it is unclear whether other mutations are associated with this resistance.

METHODS

Two types of clarithromycin-resistant strains (low- and high-resistance strains) were obtained from clarithromycin-susceptible H. pylori following exposure to low clarithromycin concentrations. The genome sequences were determined with a next-generation sequencer. Natural transformation was used to introduce the candidate mutations into strain 26695. Etest and an agar dilution method were used to determine the MICs.

RESULTS

High-resistance strains contained the mutation A2143G in the 23S rRNA genes, whereas low-resistance strains did not. There were seven candidate mutations in six genes outside of the 23S rRNA genes. The mutated sequences in hp1048 (infB), hp1314 (rpl22) and the 23S rRNA gene were successfully transformed into strain 26695 and the transformants showed an increased MIC of and low resistance to clarithromycin. The transformants containing a single mutation in infB or rpl22 (either a 9 bp insertion or a 3 bp deletion) or the 23S rRNA gene showed low MICs (0.5, 2.0, 4.0 and 32 mg/L, respectively) while the transformants containing double mutations (mutation in the 23S rRNA genes and mutation in infB or rpl22) showed higher MICs (>256 mg/L).

CONCLUSIONS

Next-generation sequencing can be a useful tool for screening mutations related to drug resistance. We discovered novel mutations related to clarithromycin resistance in H. pylori (infB and rpl22), which have synergic effects with 23S rRNA resulting in higher MICs.

[Ideal treatment for Helicobacter pylori: a systematic review]

BACKGROUND

The success rates of therapies for treating Helicobacter pylori vary greatly worldwide and the ideal treatment has yet to be clearly established.

AIMS

A systematic review was carried out to evaluate the effectiveness of current first and second-line therapies in treating H.pylori infection.

METHODS

Two researchers independently carried out Internet search engine reviews (PUBMED, EMBASE, MEDLINE) of clinical trials on adults published between 1990 and 2012 in both English and Spanish.

RESULTS

Forty-three (n=8,123) clinical trials were evaluated that included first and second-line triple, quadruple, and sequential therapies. The eradication rates of the standard triple therapy are unacceptable (≤80%) in countries where H.pylori is highly resistant to clarithromycin and metronidazole. Administration of the standard triple therapy for more than 7 days does not improve its effectiveness. No statistically significant differences were observed between the eradication rates of the quadruple therapy with bismuth and the standard triple therapy. Even though the sequential and concomitant therapies are equally successful regimens, the triple therapy with levofloxacin offers the best results as first and second-line treatment, but quinolone resistance can diminish its effectiveness. The triple therapy with levofloxacin and the sequential and concomitant treatments were superior to the standard triple regimen as first-line therapy.

CONCLUSIONS

Currently there is no ideal first or second-line treatment for achieving 100% eradication. The therapeutic order should be carried out according to the initial treatment and local antimicrobial resistance studies.

Complete Genome Sequences of Helicobacter pylori Clarithromycin-Resistant Strains

We report the complete genome sequences of two Helicobacter pylori clarithromycin-resistant strains. Clarithromycin (CLR)-resistant strains were obtained under the exposure of H. pylori strain 26695 on agar plates with low clarithromycin concentrations. The genome data provide insights into the genomic changes of H. pylori under selection by clarithromycin in vitro.

Managing peptic ulcer and gastroesophageal reflux disease in elderly Chinese patients--focus on esomeprazole

Peptic ulcer disease (PUD) and gastroesophageal reflux disease (GERD) are not uncommon in elderly patients. Clinical presentations of these acid-related disorders may be atypical in the geriatric population. Older individuals are at increased risk for poor outcomes in complicated PUD and for development of GERD complications. Multiple risk factors (eg, Helicobacter pylori [HP], use of nonsteroidal anti-inflammatory drugs [NSAIDs], aspirin) contribute to the development of PUD. Recent data has shown that HP-negative, NSAID-negative idiopathic peptic ulcers are on the rise and carry a higher risk of recurrent ulcer bleeding and mortality. Effective management of PUD in the geriatric population relies on identification and modification of treatable risk factors. Elderly patients with GERD often require long-term acid suppressive therapy. Proton pump inhibitors (PPI) including esomeprazole are effective in the treatment of reflux esophagitis, maintenance of GERD symptomatic control, and management of PUD as well as its complications. Potential safety concerns of long-term PPI use have been reported in the literature. Clinicians should balance the risks and benefits before committing elderly patients to long-term PPI therapy.

Light based anti-infectives: ultraviolet C irradiation, photodynamic therapy, blue light, and beyond

Owing to the worldwide increase in antibiotic resistance, researchers are investigating alternative anti-infective strategies to which it is supposed microorganisms will be unable to develop resistance. Prominent among these strategies, is a group of approaches which rely on light to deliver the killing blow. As is well known, ultraviolet light, particularly UVC (200-280 nm), is germicidal, but it has not been much developed as an anti-infective approach until recently, when it was realized that the possible adverse effects to host tissue were relatively minor compared to its high activity in killing pathogens. Photodynamic therapy is the combination of non-toxic photosensitizing dyes with harmless visible light that together produce abundant destructive reactive oxygen species (ROS). Certain cationic dyes or photosensitizers have good specificity for binding to microbial cells while sparing host mammalian cells and can be used for treating many localized infections, both superficial and even deep-seated by using fiber optic delivered light. Many microbial cells are highly sensitive to killing by blue light (400-470 nm) due to accumulation of naturally occurring photosensitizers such as porphyrins and flavins. Near infrared light has also been shown to have antimicrobial effects against certain species. Clinical applications of these technologies include skin, dental, wound, stomach, nasal, toenail and other infections which are amenable to effective light delivery.