Update on the first-line treatment for Helicobacter pylori infection - a continuing challenge from an old enemy

Vitamin B6 inhibits activity of Helicobacter pylori adenylosuccinate synthetase and growth of reference and clinical, antibiotic-resistant H. pylori strains

The current therapies against gastric pathogen Helicobacter pylori are ineffective in over 20% of patients. Enzymes belonging to the purine salvage pathway are considered as novel drug targets in this pathogen. Therefore, the main aim of the current study was to determine the antibacterial activity of pyridoxal 5'-phosphate (PLP), an active form of vitamin B6, against reference and clinical strains of H. pylori. Using a broad set of microbiological, physicochemical (UV absorption, LC-MS, X-ray analysis) and in silico experiments, we were able to prove that PLP inhibits adenylosuccinate synthetase (AdSS) from H. pylori by the competition with GTP (IC50eq ∼30 nM). This behaviour was attributed to formation of a Schiff base with a lysine residue (a covalent bond with Lys322 in the GTP binding site of AdSS) and was potentiated by the presence of vitamin C. This antibacterial activity of PLP gives hope for its future use against H. pylori.

The Role of Probiotics in the Eradication of Helicobacter pylori and Overall Impact on Management of Peptic Ulcer: A Study Involving Patients Undergoing Triple Therapy in Bangladesh

Background Helicobacter pylori infection has been identified to cause constantly recurring inflammation, leading to gastrointestinal tract disorders, including carcinoma. The standard triple therapy (STT), used to eradicate H. pylori, includes two antimicrobials and a proton pump inhibitor for two weeks. Other drug regimens have also been developed since H. pylori exhibits antimicrobial resistance. These regimens, including probiotics, have been shown to lower adverse drug reactions (ADR), improve drug adherence, exert bacteriostatic effect, and reduce inflammation. Objective This study intended to explore probiotic intervention for improving eradication rates and mitigating adverse effects while administrating STT.  Methods This prospective study was conducted from May to December, 2021, in the Department of Gastroenterology of Ship International Hospital, Dhaka, Bangladesh, to observe the effects of probiotics inclusion along with STT on H. pylori eradication. A total of 100 patients aged ≥18 years who tested positive for H. pylori were included. The experimental group (n=50) was given STT and probiotics, and the control group (n=50) was given only STT without probiotics for 14 days. Necessary follow-up was done six weeks after treatment. An independent sample t-test, chi-square test, and multiple regression analysis were used for statistical analysis. Result The odds of getting rapid urease test (RUT) negative results from positive were 2.06 times higher (95%CI= 0.95, 3.22, p=0.054) in the experimental group. ADRs were crucially towering in the control group (p=0.045) compared to the probiotics group. The probiotics group had a lower risk of having adverse effects by 0.54 times (95%CI=0.19, 0.84, p=0.032) than the control group. Conclusion Using probiotics and STT together to eradicate H. pylori may lower ADR and improve treatment adherence. It may also help terminate H. pylori infection more effectively. More research is required as H. pylori is very contagious and can ultimately cause life-threatening gastric cancer.

Glycyrrhizin, an inhibitor of HMGB1 induces autolysosomal degradation function and inhibits Helicobacter pylori infection

BACKGROUND

Helicobacter pylori is a key agent for causing gastric complications linked with gastric disorders. In response to infection, host cells stimulate autophagy to maintain cellular homeostasis. However, H. pylori have evolved the ability to usurp the host's autophagic machinery. High mobility group box1 (HMGB1), an alarmin molecule is a regulator of autophagy and its expression is augmented during infection and gastric cancer. Therefore, this study aims to explore the role of glycyrrhizin (a known inhibitor of HMGB1) in autophagy during H. pylori infection.

MAIN METHODS

Human gastric cancer (AGS) cells were infected with the H. pylori SS1 strain and further treatment was done with glycyrrhizin. Western blot was used to examine the expression of autophagy proteins. Autophagy and lysosomal activity were monitored by fluorescence assays. A knockdown of HMGB1 was performed to verify the effect of glycyrrhizin. H. pylori infection in in vivo mice model was established and the effect of glycyrrhizin treatment was studied.

RESULTS

The autophagy-lysosomal pathway was impaired due to an increase in lysosomal membrane permeabilization during H. pylori infection in AGS cells. Subsequently, glycyrrhizin treatment restored the lysosomal membrane integrity. The recovered lysosomal function enhanced autolysosome formation and concomitantly attenuated the intracellular H. pylori growth by eliminating the pathogenic niche. Additionally, glycyrrhizin treatment inhibited inflammation and improved gastric tissue damage in mice.

CONCLUSION

This study showed that inhibiting HMGB1 restored lysosomal activity to ameliorate H. pylori infection. It also demonstrated the potential of glycyrrhizin as an antibacterial agent to address the problem of antimicrobial resistance.

Update on the first-line treatment of Helicobacter pylori infection in areas with high and low clarithromycin resistances

Current international consensuses on Helicobacter pylori eradication therapy recommend that only regimens that reliably produce eradication rates of ⩾90% should be used for empirical treatment. The Real-world Practice & Expectation of Asia-Pacific Physicians and Patients in Helicobacter Pylori Eradication Survey also showed that the accepted minimal eradication rate in H. pylori-infected patients was 91%. According to efficacy prediction model, the per-protocol eradication rates of 7-day and 14-day standard triple therapies fall below 90% when clarithromycin resistance rate ⩾5%. Several strategies including bismuth-containing, non-bismuth-containing quadruple therapies (including sequential, concomitant, hybrid and reverse hybrid therapies), high-dose dual therapy and vonoprazan-based triple therapy have been proposed to increase the eradication rate of H. pylori infection. According to efficacy prediction model, the eradication rate of 14-day concomitant therapy, 14-day hybrid therapy and 7-day vonoprazan-based triple therapy is less than 90% if the frequency of clarithromycin-resistant strains is higher than 90%, 58% and 23%, respectively. To meet the recommendation of the consensus report and patients' expectation, local surveillance networks for resistance of H. pylori to clarithromycin are required to select appropriate eradication regimens in each geographic region. In areas with low (<5%) clarithromycin resistance (e.g. Sweden, Philippine, Myanmar and Bhutan), 7-day and 14-day standard triple therapies can be adopted for the first-line treatment of H. pylori infection with eradication rates of ⩾90%. In areas with high (⩾5%) clarithromycin resistance (most other countries worldwide) or unknown clarithromycin resistance, 14-day hybrid, 14-day reverse hybrid, 14-day concomitant and 10- to 14-day bismuth quadruple therapy can be used to treat H. pylori infection.

The efficacy of culture-guided versus empirical therapy with high-dose proton pump inhibitor as third-line treatment of Helicobacter pylori infection: A real-world clinical experience

BACKGROUND AND AIM

Most consensuses recommend culture-guided therapy as third-line Helicobacter pylori treatment. This study aimed to investigate the efficacies of culture-guided therapy and empirical therapy with high-dose proton pump inhibitor (PPI) in the H. pylori third-line treatment.

METHODS

Between August 2012 and October 2021, H. pylori-infected patients with at least two failed eradication attempts received anti-H. pylori therapy according to the results of antimicrobial sensitivity tests plus high-dose rabeprazole and/or bismuth. They were categorized into three groups: patients who had positive results of culture with equal to or more than three susceptible antibiotics were treated by culture-guided non-bismuth quadruple therapy, patients who had positive results of culture with one or two susceptible antibiotics were treated by culture-guided bismuth-containing therapy, and patients who had a negative result of culture were treated by an empirical therapy with high-dose rabeprazole plus amoxicillin, tetracycline and levofloxacin. A post-treatment assessment was conducted at week 8.

RESULTS

We recruited 126 patients. The eradication rates of culture-guided non-bismuth quadruple therapy (n = 50), culture-guided bismuth-containing therapy (n = 46) and empirical therapy (n = 30) were 84.0%, 87.0%, and 66.7% (95% confidence interval: 73.8-94.2%, 77.3-96.7%, and 49.8-83.6%), respectively. Overall, culture-guided therapy achieved a higher eradication rate than empirical therapy (85.4% vs 66.7%; 95% confidence interval, 0.4% to 37.0%, P = 0.022).

CONCLUSIONS

Culture-guided therapy with high-dose PPI achieves a higher eradication rate than empirical therapy with high-dose PPI in the third-line treatment of H. pylori infection. The eradication rate of rescue therapy with bismuth plus two susceptible antibiotics is not inferior to that with three susceptible antibiotics.

Extra virgin olive oil inhibits Helicobacter pylori growth in vitro and the development of mice gastric mucosa lesions in vivo

Helicobacter pylori infection is widespread worldwide, with more than a half of the world population infected. H. pylori antibiotic-resistant strains and non-compliance to therapy are the major causes of H. pylori eradication failure. The search for new therapies based on plant extracts is a scientific interest field. The present study was conducted to evaluate the effect in vitro of extra virgin olive oil (EVOO), hydroxytyrosol (HT), and oleuropein (Olp) against two H. pylori strains and the effect in vivo of the oral administration of EVOO on the gastric mucosa of BALB/c mice infected with this microorganism. The broth microdilution method assayed the antibacterial in vitro activity of EVOO, HT, and Olp against H. pylori strains. For in vivo studies, male BALB/c mice were infected orally with an H. pylori suspension every 72 h. Four groups were used: (1) Control, (2) H. pylori-infected (HP), (3) EVOO, and (4) HP + EVOO. Mice were sacrificed at 7, 15, and 30 days. The stomachs were removed and observed under a microscope. Scoring of the degree of erosion was determined. Samples were processed by histological techniques for light microscopy. Macroscopic analysis showed that the presence of small erosions increased, both in number and size, in the infected group. Animals infected and treated with EVOO exhibited the presence of fewer erosions, which decreased in number as the treatment progressed. The mucosa of the control and EVOO groups showed normal histological characteristics at the three times studied. The mucosa of animals infected with H. pylori showed disruptions of the lining epithelium, damage to gastric glands, and vasodilation. The mucosa of animals infected with H. pylori and treated with EVOO showed morphological characteristics similar to those of normal and EVOO mucosa. For the first time, the current study showed the effect in vitro and in vivo of EVOO and combined administration of HT and Olp against H. pylori using an animal model. Future studies are needed to establish the mechanism of EVOO’s action at the gastric mucosa level to propose this product as a natural antimicrobial agent for the treatment of gastric H. pylori infections.

Current guidelines for Helicobacter pylori treatment in East Asia 2022: Differences among China, Japan, and South Korea

Helicobacter pylori (H. pylori) infection is highly prevalent in East Asia. The overall seroprevalence rate of H. pylori infection is 44.2% in China, 37.6%-43.2% in Japan, and 51.0% in South Korea. H. pylori can cause peptic ulcer disease and gastric cancer. East Asian countries have high rates of gastric cancer (age-standardized incidence rate: 20-30 per 100000). The Kyoto global consensus report emphasized that H. pylori gastritis should be considered the main cause for the development of gastric cancer. H. pylori treatment guidelines in China, Japan, and South Korea have recently been revised according to data from each of those countries. However, emerging antibiotic resistance is an important barrier to H. pylori eradication. The recommended H. pylori treatment regimens differ among those three East Asian countries. In this review, recent guidelines and up-to-date research on H. pylori treatment regimens from China, Japan, and South Korea are discussed.

Helicobacter pylori infection treatment in the United States: clinical consequences and costs of eradication treatment failure

INTRODUCTION

Helicobacter pylori (Hp) is causal in benign and malignant gastrointestinal diseases. Accordingly, current guidelines recommend Hp eradication in patients with active infection. Unfortunately, treatment failure is common, exposing patients to complications associated with persistent Hp infection and consequences of repeated treatment, including promotion of antibiotic resistance. In the United States (US), data regarding eradication rates with available therapies are limited. Moreover, the clinical and economic burden of eradication treatment failure have not been thoroughly described.

AREAS COVERED

We aimed to characterize Hp eradication rates and the clinical consequences and associated costs of persistent Hp infection among US adults. We conducted focused literature reviews using initial searches in Embase, MEDLINE, and Cochrane Database of Systematic Reviews via Ovid followed by manual searches to identify relevant publications.

EXPERT OPINION

Hp eradication rates were suboptimal, with most studies reporting rates ≤80% with clarithromycin-based triple therapy and bismuth quadruple therapy. There was direct evidence supporting numerous benefits of successful Hp eradication, including decreased risk of recurrent or complicated peptic disease and non-cardia gastric cancer. Cost benefits of eradication were related to mitigation of conditions associated with persistent Hp infection, (e.g. complicated peptic ulcer disease, and gastric cancer) which altogether exceed US$5.3 billion.

Detection of clarithromycin resistance and 23SrRNA point mutations in clinical isolates of Helicobacter pylori isolates: Phenotypic and molecular methods

BACKGROUND AND OBJECTIVES

Peptic ulcer disease, chronic gastritis, and stomach cancer are all caused by H. pylori. The most notable drug for the treatment is the antibiotic clarithromycin, which is currently the drug of choice. H. pylori clarithromycin resistance has been associated with point mutations in 23srRNA, the most prominent of which are A2143 and A2144G. In H. pylori bacteria, methylase synthesis, macrolide-inactivating enzyme activity, and active efflux have all been found to be resistance mechanisms. The goal of the study is to determine how resistant H. pylori is to clarithromycin and what the minimum inhibitory concentration is for various antimicrobials. Furthermore, gastro-endoscopy will be performed on Iraqi patients to detect the presence of A2143G and A2144G point mutations in Helicobacter pylori infections, as diagnosed from the pyloric region and other anatomical regions.

METHODS

One hundred fifteen samples were collected from patients strongly suspected of H. pylori infection presented for upper gastrointestinal endoscopy at Ramadi Teaching Hospitals and Private Clinics for the period from January 2020 until February 2021. Specimens were cultured on brain heart infusion agar containing various antibiotics and were incubated at 37 °C under microaerophilic conditions. For identification of H. pylori, isolates of the biochemical tests and RT-PCR assay were applied. The Epsilometer test was used in the antibiotic susceptibility testing as dependent on the CLSI standard. The Restriction Fragment Length Polymorphism technique was used to determine point mutations.

RESULTS

In total, 55 (47.8%) Helicobacter pylori isolates were cultured from the 115 biopsy specimens, among which 16 (29.1%), 38 (69.1%), 20 (36.4%), and 40 (72.7%) revealed some degree of resistance to levofloxacin, clarithromycin, ciprofloxacin, and metronidazole, respectively. The frequency of A2144G and A2143 point mutations were 23 (60.5%) and 19 (50%), respectively.

CONCLUSIONS

According to our results, Helicobacter pylori showed high resistance to clarithromycin. Our results demonstrate the requirement for antibiotic susceptibility testing and molecular methods in selecting drug regimens.

A randomized clinical trial comparing triple therapy versus non-bismuth based quadruple therapy for the eradication of Helicobacter Pylori in Kuwait

Introduction:

Helicobacter pylori-induced chronic infection is associated with peptic ulcer, chronic gastritis, gastric cancer, and increasing antibiotic resistance. We aimed to evaluate the efficacy of clarithromycin-based triple therapy and non-bismuth based quadruple therapy for eradicating H. pylori in patients with chronic gastritis in Kuwait.

Methods:

We enrolled a total of 603 treatment-naive dyspeptic patients with gastric biopsy-proven chronic gastritis secondary to H. pylori in a prospective, open-label, randomized study. Patients were randomized into two groups: a group received the standard triple therapy (omeprazole, amoxicillin, and clarithromycin) for 14 days and a group received quadruple therapy (omeprazole, amoxicillin, clarithromycin, and metronidazole) for 14 days. All patients were tested for the eradication of H. pylori by carbon-13 urea breath test 1 month after eradication therapy.

Results:

The overall eradication rate was 63.2%. The eradication rates in intention-to-treat (ITT) and per protocol (PP) population were 58.4% and 64.6%, respectively, in triple therapy group. In the quadruple therapy group, the eradication rates in ITT and PP population were 68.0% and 78.5%, respectively, with a statistically significant higher eradication rate in patients treated by quadruple therapy than the triple therapy (P < 0.01). Multivariate logistic regression analysis revealed that treatment regimen was the only significant predictor for successful H. pylori eradication. The most common adverse events were abnormal taste, headache, dizziness, and abdominal pain.

Conclusion:

Non-bismuth based quadruple therapy is more effective than standard clarithromycin-based triple therapy for eradicating H. pylori in patients with chronic gastritis.

ClinicalTrials.gov Identifier: NCT04617613

Tailored susceptibility-guided therapy via gastric juice PCR for the first-line H. pylori eradication, a randomized controlled trial

BACKGROUND/PURPOSE

Clarithromycin-based standard triple therapy is still commonly adopted by 81.4% of physicians in real-world practice but yields low eradication rates. Therefore, we conducted this study to compare the efficacy of gastric juice-guided therapy for first-line eradication with the standard triple therapy, in order to provide an alternative to real-world practice.

METHODS

A total of 182 treatment-naïve Hp-infected patients were included and randomly allocated to either susceptibility-guided therapy (SGT) with gastric juice PCR or Clarithromycin-based standard triple therapy (STT) for 7 days.

RESULTS

The intention-to-treat eradication rates were 89% (81/91) in SGT and 75.8% in STT (p < 0.031). The per-protocol eradication rates were 91.0% (81/89) in SGT and 79.3% (69/87) in STT (p < 0.034). Among the subgroups of different antibiotic resistance, patients with SGT demonstrated superior eradication rates (91.7% vs 45.5%, p < 0.027) in the subgroup of both clarithromycin resistance and levofloxacin resistance.

CONCLUSION

This prospective randomized controlled trial demonstrated the reliable efficacy of susceptibility-guided therapy via gastric juice PCR for the first-line Hp eradication. In Asia-Pacific area, where standard triple therapy is still adopted by the majority of the physicians, it is a recommended alternative to overcome the increasing antibiotic resistance.

A comprehensive method for determining cellular uptake of purine nucleoside phosphorylase and adenylosuccinate synthetase inhibitors by H. pylori

Due to the growing number of Helicobacter pylori strains resistant to currently available antibiotics, there is an urgent need to design new drugs utilizing different molecular mechanisms than those that have been used up to now. Enzymes of the purine salvage pathway are possible targets of such new antibiotics because H. pylori is not able to synthetize purine nucleotides de novo. The bacterium's recovery of purines and purine nucleotides from the environment is the only source of these essential DNA and RNA building blocks. We have identified formycins and hadacidin as potent inhibitors of purine nucleoside phosphorylase (PNP) and adenylosuccinate synthetase (AdSS) from H. pylori - two key enzymes of the purine salvage pathway. However, we have found that these compounds are not effective in H. pylori cell cultures. To address this issue, we have developed a universal comprehensive method for assessing H. pylori cell penetration by drug candidates, with three alternative detection assays. These include liquid chromatography tandem mass spectrometry, UV absorption, and inhibition of the target enzyme by the tested compound. Using this approach, we have shown that cellular uptake by H. pylori of formycins and hadacidin is very poor, which reveals why their in vitro inhibition of PNP and AdSS and their effect on H. pylori cell cultures are so different. The cell penetration assessment method developed here will be extremely useful for validating the cellular uptake of other drug candidates, facilitating the design of new potent therapeutic agents against H. pylori. KEY POINTS: • A method for assessing H. pylori cells penetration by drug candidates is described. • Three alternative detection assays that complement each other can be used. • The method may be adapted for other bacteria as well.

A Comparison between 10-day and 12-day Concomitant Regimens for Helicobacter Pylori Eradication: A Randomized Clinical Trial

BACKGROUND

Helicobacter pylori (H. pylori) infection is one of the most common bacterial infections worldwide, which is associated with peptic ulcer disease and gastric cancer. In this study, we compared the efficacy of 10-day versus 12-day concomitant therapy as the first-line treatment for H. pylori eradication in Iran.

METHODS

218 patients with peptic ulcer disease and naïve H. pylori infection, were randomly divided into two groups to receive either 10-day or 12-day concomitant regimens, composed of pantoprazole 40 mg, amoxicillin 1000 mg, clarithromycin 500 mg, and metronidazole 500 mg, all given twice daily. Eight weeks after treatment, H. pylori eradication was assessed by 14C- urea breath test. The trial was registered in the Iranian Registry of Clinical Trials (code: IRCT20170521034070N2).

RESULTS

212 patients completed the study. According to the intention to treat analysis, the eradication rates were 83.6% (95% CI: 76.6-90.5) and 88.8% (95% CI: 82.8-94.7) in 10-day and 12-day concomitant therapy groups, respectively (p = 0.24). Per-protocol eradication rates were 85.9% (95% CI: 79.3–92.4) and 92.6% (95% CI: 87.6–97.5), respectively (p = 0.19). The rates of severe side effects were not statistically different between the two groups (3.6% vs. 8.1%; p = 0.428).

CONCLUSION

12-day concomitant therapy could achieve ideal eradication rates by both intention to treat and perprotocol analyses. In order to reduce the cost of drugs and the rate of adverse effects of therapy, among 10-day and 12day regimens, 12-day concomitant therapy seems to be a good alternative to 14-day concomitant therapy that has been suggested by international guidelines.

Reverse hybrid therapy achieves a similar eradication rate as standard hybrid therapy for Helicobacter pylori infection

BACKGROUND

Reverse hybrid therapy is a simplified hybrid treatment for Helicobacter pylori infection. It achieves a higher eradication rate than standard triple therapy. This study aimed to compare the efficacies of reverse hybrid and hybrid therapies in the treatment of H. pylori infection.

METHODS

From September 2008 to September 2017, 490 H. pylori-infected patients who received 14 days of reverse hybrid therapy (proton pump inhibitor plus amoxicillin for 14 days and clarithromycin plus metronidazole for the initial 7 days; n = 252) or hybrid therapy (proton pump inhibitor plus amoxicillin for 14 days and clarithromycin plus metronidazole for the final 7 days; n = 238) were included in this retrospective cohort study. Helicobacter pylori status was examined 6-8 weeks after therapy.

RESULTS

The eradication rates of the reverse hybrid and hybrid therapies by modified intention-to-treat analysis were comparable (96.4% vs 96.6%; p = 0.899). There were no differences in the efficacy of eradication between therapies for clarithromycin-resistant strains (87.0% vs 90.0%) or metronidazole-resistant strains (97.7% vs 100.0%). In addition, there were comparable frequencies of adverse events for both treatments (18.7% vs 13.0%) and treatment adherence (94.4% vs 97.1%).

CONCLUSION

Reverse hybrid therapy can achieve a similar eradication rate to hybrid therapy for H. pylori infection.

Short-term and long-term impacts of Helicobacter pylori eradication with reverse hybrid therapy on the gut microbiota

BACKGROUND AND AIMS

Anti-Helicobacter pylori therapy may lead to the growth of pathogenic or antibiotic-resistant bacteria in the gut. The study aimed to investigate the short-term and long-term impacts of H. pylori eradication with reverse hybrid therapy on the components and macrolide resistance of the gut microbiota.

METHODS

Helicobacter pylori-related gastritis patients were administered a 14-day reverse hybrid therapy. Fecal samples were collected before treatment and at the end of week 2, week 8, and week 48. The V3-V4 region of the bacterial 16S rRNA gene in fecal specimens was amplified by polymerase chain reaction and sequenced on Illumina MiSeq platform. Additionally, amplification of erm(B) gene (encoding erythromycin resistance methylase) was performed.

RESULTS

Reverse hybrid therapy resulted in decreased relative abundances of Firmicutes (from 62.0% to 30.7%; P < 0.001) and Actinobacteria (from 3.4% to 0.6%; 0.032) at the end of therapy. In contrast, the relative abundance of Proteobacteria increased from 10.2% to 49.1% (0.002). These microbiota alterations did not persist but returned to the initial levels at week 8 and week 48. The amount of erm(B) gene in fecal specimens was comparable with the pretreatment level at week 2 but increased at week 8 (0.025) and then returned to the pretreatment level by week 48.

CONCLUSIONS

Helicobacter pylori eradication with reverse hybrid therapy can lead to short-term gut dysbiosis. The amount of erm(B) gene in the stool increased transiently after treatment and returned to the pretreatment level at 1-year post-treatment.

Effect of Drug Combination on Omeprazole Metabolism by Cytochrome P450 2C19 in Helicobacter pylori Eradication Therapy

Helicobacter pylori (H. pylori) infection is common and can result in gastric and duodenal ulcers, and in some cases, gastric lymphoma and cancer. Omeprazole (OMP)-in combination with clarithromycin (CLR), amoxicillin (AMX), tinidazole (TND), or metronidazole (MET)-is used in double or triple combination therapy for eradication of H. pylori. However, the roles of the drugs other than OMP are not clearly understood. Therefore, in the present study, we aimed to investigate any effects of these drugs on OMP metabolism by wild-type CYP2C19 using spectroscopy and enzyme kinetics. The dissociation constants (K_d) for CYP2C19 with OMP, CLR, AMX, TND, and MET were 8.6, 126, 156, 174, and 249 µM, respectively. The intrinsic clearance of OMP was determined to be 355 mL/min/µmol of CYP2C19. Metabolism of OMP was significantly inhibited by 69, 66, 28, and 40% in the presence of CLR, TND, AMX, and MET, respectively. Moreover, the combination of CLR and TND resulted in 76% inhibition of OMP metabolism, while the combination of AMX and MET resulted in 48% inhibition of OMP metabolism. Both combinations of drugs not only have antibacterial effects, but also enhance the effect of OMP by inhibiting its metabolism by CYP2C19. These results indicate that drug-drug interactions of co-administered drugs can cause complex effects, providing a basis for OMP dose adjustment when used in combination therapy for H. pylori eradication.

Gastric juice-based PCR assay: An alternative testing method to aid in the management of previously treated Helicobacter pylori infection

BACKGROUND

Culture of Helicobacter pylori with previous eradication failure has been emphasized in clinical guidelines. The current unmet need to manage previously treated H pylori is one tool with diagnostic accuracy and ability for antibiotics susceptibility. Gastric juice PCR can provide diagnosis and antibiotics susceptibility; however, whether treatment failure affects its accuracy remains uninvestigated. Our study aimed to investigate diagnostic accuracy and antibiotics susceptibility of juice PCR in previously treated H pylori and to compare with the current standard of culture.

METHODS

We categorized all 547 patients into treatment-naïve, post-1st treatment, post-2nd treatment, and post-3rd treatment. Helicobacter pylori infection was confirmed using gold standards. Sensitivity, specificity, positive predictive value, negative predictive value, receiver operating characteristic (ROC) curve and area under ROC curve (AUC) of juice PCR and culture were calculated. Intra-gastric H pylori density was evaluated. Lastly, the antibiotics susceptibility results of gastric juice and culture were compared.

RESULTS

Our findings demonstrated AUC was higher in juice PCR than culture in all patients (96.7% vs 91.3%, P < 0.0001). The superiority of juice PCR was statistically significant in previously treated patients (P < 0.0001) but not in treatment-naïve patients (P = 0.13). Antral H pylori density was less marked in previously treated patients (P = 0.014). The comparisons of PCR-RFLP and E-test for Clarithromycin resistance showed reliable AUC = 89.8%.

CONCLUSION

Compared with the current standard of culture, the gastric juice PCR contains the strengths of performing the antibiotics susceptibility and overcomes the shortcomings of low accuracy. Consequently, gastric juice PCR suits the unmet need to manage previously treated H pylori.

Synthesis, Urease Inhibition and Molecular Modelling Studies of Novel Derivatives of the Naturally Occurring β-Amyrenone

Urease enzyme (UE) has been reported to be a potent virulence factor for Helicobacter pylori (HP) bacteria indicated to be responsible for various gastrointestinal diseases. Therefore, the spread of HP, currently regarded by the World Health Organization as a class 1 carcinogen, could be better controlled by targeting UE. It is in this line that we have synthesized three new derivatives (2-4) of the naturally occurring olean-12-en-3-one (1), which was previously isolated from the figs of Ficus vallis-choudae Delile (Moraceae). Among the synthesized compounds, 3 and 4 contain an indole moiety. Their structures were unambiguously assigned by spectroscopic and spectrometric techniques (1D-NMR, 2D-NMR and MS). The starting material and the synthesized compounds were screened for UE inhibition activity, and showed significant activities with IC₅₀ values ranging from 14.5 to 24.6 μM, with compound (1) being the most potent as compared to the positive control thiourea (IC₅₀ = 21.6 μM). Amongst the synthetic derivatives, compound 4 was the most potent (IC₅₀ = 17.9 μM), while the others showed activities close to that of the control. In addition, molecular docking study of target compounds 2-4 was performed in an attempt to explore their binding mode for the design of more potent UE inhibitors.

Modified quadruple therapy versus bismuth-containing quadruple therapy in first-line treatment of Helicobacter pylori infection in Korea; rationale and design of an open-label, multicenter, randomized controlled trial

BACKGROUND

Clarithromycin-containing triple regimen for eradication of Helicobacter pylori is no longer acceptable in Korea due to high clarithromycin resistance. Concomitant therapy or bismuth-containing quadruple therapy is recommended as an alternative regimen. A recent study in Korea has shown that modified quadruple therapy has comparable efficacy and safety to concomitant therapy as a first-line regimen. However, there has been no comparative study of modified quadruple therapy with bismuth-containing quadruple therapy. The aim of this study is to compare the efficacy and safety of modified quadruple therapy with those of bismuth-containing quadruple therapy as a first-line regimen and to present the phenotypic and genotypic antibiotic resistance profile of H pylori.

METHODS

This study is an open-label, multicenter, randomized controlled trial. We are recruiting subjects endoscopically diagnosed with H pylori infection from 2 hospitals in Korea. Subjects will be randomly allocated either to modified quadruple therapy (proton-pump inhibitor bid, amoxicillin 1 g bid, metronidazole 500 mg tid, bismuth subcitrate 300 mg qid daily) or bismuth-containing quadruple therapy (proton-pump inhibitor bid, tetracycline 500 mg qid, metronidazole 500 mg tid, bismuth subcitrate 300 mg qid daily) for 14 days. The rate of eradication success and adverse events will be checked at least 4 weeks after the treatment. Antibiotic resistance will be established using both a bacterial culture with agar dilutions and DNA sequencing of the clarithromycin resistance point mutations in the 23S rRNA gene of H pylori.

CONCLUSION

The results of this study will provide solid evidence for determining the optimal treatment regimen for first-line H pylori eradication in Korea.

The Resistance Rate of Helicobacter Pylori to Clarithromycin and Main Mutations on Bacterial Genomic Responsible for Bacterial Resistance: A Comparative Study in Children and Adults, Tehran and Iran

BACKGROUND

High resistance to common antibiotics has become a huge global dilemma in eradicating Helicobacter Pylori infection in both children and adults. The great concern is about the resistance to different classes of antibiotics especially Clarithromycin because of its widespread use.

OBJECTIVES

The present survey aimed to assess the resistance rate to Clarithromycin in Helicobacter Pylori isolated in patients aged less than 15 years as compared to patients older than 15 years of age.

METHODS

In this cross-sectional study, total 72 patients with upper gastrointestinal symptoms requiring diagnostic endoscopy referred to Rasoul-e-Akram Hospital in Tehran during one year (August 2015 to August 2016). Helicobacter Pylori infection was diagnosed in patients using the Rapid Urease Test. The antibiotics resistance was detected in genomes using the real-time polymerase chain reaction (PCR) on 23S rRNA gene.

RESULTS

In total 72 patients, 36 cases aged less than or equal to 15 years and 36 patients were older than 15 years. Of all patients in this study, 17 cases were detected with gene mutations or polymorphisms related to resistance to Clarithromycin. Overall prevalence rate of resistance was reported 23.61%. Three polymorphisms on 23S rRNA gene including A2142G, A2142C, and A2143G were revealed in 47.1%, 5.9%, and 47.1% of patients, respectively. The bacterial resistance to Clarithromycin was observed more prevalent in patients that aged older than 15 years compared to patients younger than 15 years of age. Also, frequent consumption of any type of antibiotics was significantly associated with the higher resistance of bacterium to Clarithromycin.

CONCLUSION

The results of our study regarding the resistance of Helicobacter Pylori to Clarithromycin were similar to findings of other studies around the world. But, the Clarithromycin resistance rate was reported higher in patients older than 15 years of age and those patients who repeatedly received different types of antibiotics regardless of their age. Of all mutations in bacterial genome, the prominent mutations responsible for bacterial resistance to Clarithromycin included A2142C, A2142G, and A2143G nucleotide polymorphism on 23S rRNA gene.

Validation of a Blood Biomarker for Identification of Individuals at High Risk for Gastric Cancer

BACKGROUND

Helicobacter pylori is the leading cause of gastric cancer, yet the majority of infected individuals will not develop neoplasia. Previously, we developed and replicated serologic H. pylori biomarkers for gastric cancer risk among prospective cohorts in East Asia and now seek to validate the performance of these biomarkers in identifying individuals with premalignant lesions.

METHODS

This cross-sectional study included 1,402 individuals from Linqu County screened by upper endoscopy. H. pylori protein-specific antibody levels were assessed using multiplex serology. Multivariable-adjusted logistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for prevalent intestinal metaplasia, indefinite dysplasia, or dysplasia, compared with superficial or mild atrophic gastritis.

RESULTS

Compared with individuals seronegative to Omp and HP0305, individuals seropositive to both were seven times more likely to have precancerous lesions (OR, 7.43; 95% CI, 5.59-9.88). A classification model for precancerous lesions that includes age, smoking, and seropositivity to H. pylori, Omp, and HP0305 resulted in an area under the curve (AUC) of 0.751 (95% CI, 0.725-0.777), which is significantly better than the same model, including the established gastric cancer risk factor CagA (AUC, 0.718; 95% CI, 0.691-0.746, P _difference = 0.0002).

CONCLUSIONS

The present study of prevalent precancerous gastric lesions provides support for two new serum biomarkers of gastric cancer risk, Omp and HP 0305.

IMPACT

Our results support further research into the serological biomarkers Omp and HP0305 as possible improvements over the established virulence marker CagA for identifying individuals with precancerous lesions in East Asia.

Helicobacter pylori eradication with bismuth quadruple therapy leads to dysbiosis of gut microbiota with an increased relative abundance of Proteobacteria and decreased relative abundances of Bacteroidetes and Actinobacteria

BACKGROUND

Bismuth quadruple therapy is the treatment of choice for the first-line therapy of Helicobacter pylori infection in areas of high clarithromycin resistance. Currently, the impact of the promising treatment on gut microbiota remains unclear.

AIM

To investigate the short-term and long-term impacts of bismuth quadruple therapy on gut microbiota.

METHODS

Adult patients with H. pylori-related gastritis were treated with 14-day bismuth quadruple therapy. Fecal samples were collected before treatment at week 2, week 8, and week 48. Nucleic acid extraction from fecal samples was performed. The V3-V4 region of the bacterial 16S rRNA gene was amplified by polymerase chain reaction and sequenced with the MiSeq followed by data analysis using Qiime pipeline.

RESULTS

Eleven patients received complete follow-up. Before treatment, the most abundant phyla were Firmicutes (45.3%), Bacteroidetes (24.3%), Proteobacteria (9.9%), and Actinobacteria (5.0%). At the end of bismuth therapy, the relative abundances of Bacteroidetes and Actinobacteria decreased to 0.5% (P < .001) and 1.3% (P = .038), respectively. Additionally, the relative abundance of Verrucomicrobia also decreased from 3.2% to 1.11E-3% (P = .034). In contrast, the relative abundances of Proteobacteria and Cyanobacteria increased (P < .001 and P = .003, respectively). At week 8, the relative abundances of all phyla restored to the levels at baseline. The relative abundances of all phyla at week 48 also did not significantly differ from those at baseline. During eradication therapy, 6 patients (55%) reported at least 1 adverse event. The relative abundance of phylum Proteobacteria in patients with adverse effects was more than that in patients without adverse effects (68.7% ± 8.8% vs 43.4% ± 25.5%; P = .048).

CONCLUSIONS

Bismuth quadruple therapy for H. pylori eradication can lead to short-term dysbiosis of gut microbiota. The increase in Proteobacteria in gut microbiota may attribute to the development of adverse effects during bismuth quadruple therapy.

Immunization with a recombinant fusion protein protects mice against Helicobacter pylori infection

More than 50% of the world's population is infected with the bacterium Helicobacter pylori. If left untreated, infection with H. pylori can cause chronic gastritis and peptic ulcer disease, which may progress into gastric cancer. Owing to the limited efficacy of anti-H. pylori antibiotic therapy in clinical practice, the development of a protective vaccine to combat this pathogen has been a tempting goal for several years. In this study, a chimeric gene coding for the antigenic parts of H. pylori FliD, UreB, VacA, and CagL was generated and expressed in bacteria and the potential of the resulting fusion protein (rFUVL) to induce humoral and cellular immune responses and to provide protection against H. pylori infection was evaluated in mice. Three different immunization adjuvants were tested along with rFUVL: CpG oligodeoxynucleotides (CpG ODN), Addavax, and Cholera toxin subunit B. Compared to the control group that had received PBS, vaccinated mice showed significantly higher cellular recall responses and antigen-specific IgG2a, IgG1, and gastric IgA antibody titers. Importantly, rFUVL immunized mice exhibited a reduction of about three orders of magnitude in their stomach bacterial loads. Thus, adjuvanted rFUVL might be considered as a promising vaccine candidate for the control of H. pylori infection.