Colloidal bismuth subcitrate impedes proton entry into Helicobacter pylori and increases the efficacy of growth-dependent antibiotics

Helicobacter pylori infection

Helicobacter pylori infection causes chronic gastritis, which can progress to severe gastroduodenal pathologies, including peptic ulcer, gastric cancer and gastric mucosa-associated lymphoid tissue lymphoma. H. pylori is usually transmitted in childhood and persists for life if untreated. The infection affects around half of the population in the world but prevalence varies according to location and sanitation standards. H. pylori has unique properties to colonize gastric epithelium in an acidic environment. The pathophysiology of H. pylori infection is dependent on complex bacterial virulence mechanisms and their interaction with the host immune system and environmental factors, resulting in distinct gastritis phenotypes that determine possible progression to different gastroduodenal pathologies. The causative role of H. pylori infection in gastric cancer development presents the opportunity for preventive screen-and-treat strategies. Invasive, endoscopy-based and non-invasive methods, including breath, stool and serological tests, are used in the diagnosis of H. pylori infection. Their use depends on the specific individual patient history and local availability. H. pylori treatment consists of a strong acid suppressant in various combinations with antibiotics and/or bismuth. The dramatic increase in resistance to key antibiotics used in H. pylori eradication demands antibiotic susceptibility testing, surveillance of resistance and antibiotic stewardship.

The cure rate of 10-day bismuth-containing quadruple therapy for Helicobacter pylori eradication is equivalent to 14-day: a systematic review and meta-analysis

Helicobacter pylori (H. pylori) infection is a major cause of duodenal ulcers, gastric ulcers, and gastric cancer. However, the optimal duration for H. pylori eradication therapy remains controversial. Most studies have mainly focused on triple therapy, and there is insufficient research on bismuth-containing quadruple therapy. The aim of this study was to compare the clinical effect of the 10-day bismuth-containing quadruple treatment regimen with the 14-day regime in eradicating H. pylori. We searched PubMed, Embase, Web of Science, and the Cochrane Library for randomized controlled trials published in English until May 2022 according to the eligibility criteria. Summary risk ratios (RRs) and 95% confidence intervals (CIs) for eradication rates, adverse effects, and compliance were calculated for included studies. Four studies, involving 1173 patients, were eligible for inclusion. The eradication rate was similar in the 10-day treatment group and the 14-day treatment group in the intention-to-treat analysis (RR 0.97, 95% CI 0.93 to 1.01). Meanwhile, the incidence of adverse effects was lower in patients who received 10 days of treatment than in those who received 14 days of treatment and patients' compliance was almost the same between two groups. Compared to the 14-day bismuth-containing quadruple regimens, 10-day regimens had similar efficacy and lower incidence of adverse effects. Therefore, the 10-day regimen is safe and well-tolerated and should be recommended for H. pylori infection.

The Effect of Quadruple Therapy with Polaprezinc or Bismuth on Gut Microbiota after Helicobacter pylori Eradication: A Randomized Controlled Trial

Background: Quadruple therapy with polaprezinc provided an alternative to Helicobacter pylori eradication; however, the effect on gut microbiota remains uncertain. This study aims to identify whether polaprezinc-containing quadruple therapy causes adverse microbiota effects among asymptomatic adults, compared with bismuth therapy. Methods: This was a randomized control trial. One hundred asymptomatic H. pylori-infected adults were randomly (1:1) assigned to two treatment groups (polaprezinc-containing therapy, PQT; or bismuth-containing therapy, BQT). Fecal samples were collected from subjects before and 4−8 weeks after therapy. Samples were sequenced for the V4 regions of the 16S rRNA gene. Results: The relative abundance of the three dominant bacterial phyla (Bacteroidota, Firmicutes, and Proteobacteria) accounted for more than 95% of each treatment group. The alpha diversity between eradications that succeeded and those that failed had no significant difference (p > 0.05). After successful eradication, the alpha diversity in the BQT group decreased in comparison with the baseline (p < 0.05). Subjects who were successfully eradicated by BQT showed considerably lower alpha diversity indices than those of the PQT at follow-up (p < 0.05). The abundance of Parasutterella in subjects who were successfully eradicated by PQT was four times greater than that of BQT (q < 0.05). Conclusion: A 14-day PQT may be superior to BQT in maintaining short-term gut microbiota homeostasis after H. pylori treatment. Our findings preliminarily provide evidence of the short-term impacts of the gut microbiota after PQT treatment of H. pylori infection.

In vitro evaluation of the antibacterial effect of colloidal bismuth subcitrate on Porphyromonas gingivalis and its biofilm

OBJECTIVE

To investigate the antibacterial and anti-biofilm effects of colloidal bismuth subcitrate (CBS) on Porphyromonas gingivalis (P. gingivalis) in its planktonic and biofilm forms and also compare it with that of 0.2% chlorhexidine (CHX).

DESIGN

The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of CBS were determined by the microdilution method; the bacteriostatic rate of CBS was determined by the MTT assay; the effect of CBS on the membrane integrity of P. gingivalis was investigated by the flow cytometric methods. The effects of CBS on the biomass and bacterial activity of biofilm were investigated. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were used to investigate the activity and structure of biofilms.

RESULTS

The MIC and MBC values were 18.75 µg/mL and 37.5 µg/mL. CBS could damage the cell membrane of P. gingivalis. CBS effectively inhibited biofilm formation and promoted dissociation at higher concentrations of 37.5 µg/mL and 75 µg/mL, respectively. The results also indicated an altered biofilm structure and reduced biofilm thickness and bacterial aggregation.

CONCLUSIONS

CBS affected the metabolic and physiological processes of P. gingivalis, inhibited the formation of biofilm, and disrupted the mature biofilm.

Efficacy and safety of bismuth-based quadruple therapy for Helicobacter pylori eradication in children

OBJECTIVES

To evaluate the efficacy and safety of a 10-day quadruple therapy containing colloidal bismuth sub-citrate (CBS), esomeprazole (ESO), amoxicillin (AMO), and metronidazole (MET) for Helicobacter pylori (H. pylori) eradication in children.

METHODS

Monocentric, open-label, prospective, single-arm clinical trial in children aged 6-17 years with H. pylori infection. The study was carried out on consecutive patients with upper gastrointestinal symptoms and H. pylori infection confirmed by histology and culture of gastric biopsies. The outcome was evaluated using a ¹³ C-urea breath test 8-10 weeks post-therapy. Adverse events and compliance were evaluated by daily journal and pill counting.

RESULTS

A total of 36 children fulfilling the inclusion criteria were enrolled. Eight (22.2%) of them had a prior H. pylori eradication treatment. Thirteen (36.1%) patients were infected by a strain resistant to MET and 8 (22.2%) by a strain resistant to both MET and Clarithromycin (CLA). In the intention-to-treat population (ITT), eradication was achieved in 35/36 patients (95%CI: 85%-99%). Twenty-three children reported at least one adverse event (63.8%), mostly mild (nausea, vomiting, abdominal pain, diarrhea, dark stool, metallic taste, headache, and rash). The compliance rate was high, with 30 (83.3%) patients taking >90% of the treatment.

CONCLUSION

10-day quadruple therapy containing CBS, ESO, AMO, and MET for H. pylori eradication in children is a safe and very effective solution, especially for previously treated patients and those infected with double resistant strains.

Facile Synthesis of Zn-Doped Bi2O3 Nanoparticles and Their Selective Cytotoxicity toward Cancer Cells

Bismuth (III) oxide nanoparticles (Bi2O3 NPs) have shown great potential for biomedical applications because of their tunable physicochemical properties. In this work, pure and Zn-doped (1 and 3 mol %) Bi2O3 NPs were synthesized by a facile chemical route and their cytotoxicity was examined in cancer cells and normal cells. The X-ray diffraction results show that the tetragonal phase of β-Bi2O3 remains unchanged after Zn-doping. Transmission electron microscopy and scanning electron microscopy images depicted that prepared particles were spherical with smooth surfaces and the homogeneous distribution of Zn in Bi2O3 with high-quality lattice fringes without distortion. Photoluminescence spectra revealed that intensity of Bi2O3 NPs decreases with increasing level of Zn-doping. Biological data showed that Zn-doped Bi2O3 NPs induce higher cytotoxicity to human lung (A549) and liver (HepG2) cancer cells as compared to pure Bi2O3 NPs, and cytotoxic intensity increases with increasing concentration of Zn-doping. Mechanistic data indicated that Zn-doped Bi2O3 NPs induce cytotoxicity in both types of cancer cells through the generation of reactive oxygen species and caspase-3 activation. On the other hand, biocompatibility of Zn-doped Bi2O3 NPs in normal cells (primary rat hepatocytes) was greater than that of pure Bi2O3 NPs and biocompatibility improves with increasing level of Zn-doping. Altogether, this is the first report highlighting the role of Zn-doping in the anticancer activity of Bi2O3 NPs. This study warrants further research on the antitumor activity of Zn-doped Bi2O3 NPs in suitable in vivo models.

Bismuth salts with versus without acid suppression for Helicobacter pylori infection: A transmission electron microscope study

BACKGROUND

Bismuth oxychloride produced by interaction of bismuth compounds with gastric acid is believed to damage Helicobacter pylori. The effect of bismuth salts on H. pylori in the presence of strong acid suppression is unknown. This randomized trial aimed to determine effects of bismuth subcitrate on H. pylori with and without acid suppression.

METHODS

H. pylori -positive participants were allocated (1:1:1) to receive (a) no treatment (control), (b) colloidal bismuth subcitrate (CBS, 125 mg/tab), or (c) CBS plus high-dose proton-pump inhibitor (PPI), esomeprazole 40 mg q.i.d. for 3 days. In the treatment groups, CBS was given: 1 dose, 1 hour before endoscopy, 1 dose, 4 hours before endoscopy, or q.i.d. 24 hours before endoscopy. The study end-points were evaluated using transmission electron microscopy to observe the morphological changes of H. pylori in antral and corpus biopsies.

RESULTS

Twenty-seven H. pylori carriers were enrolled in this trial with qualitative end-points. In the no treatment group, active budding and replication of H. pylori were observed. In the CBS group, cellular swelling, vacuolization, structural degradation, and cell wall eruption of H. pylori were observed, with no apparent association with when the CBS was given. Among those receiving high-dose PPI-plus CBS or CBS only, there were no differences in number of H. pylori present or severity of bacterial damage whether CBS was given 1, 4, or 24 hours before endoscopy.

CONCLUSIONS

Based on direct morphological evaluation, the toxic effect of CBS treatment on H. pylori was demonstrated independent of acid suppression with PPI.

Antofloxacin-based bismuth quadruple therapy is safe and effective in Helicobacter pylori eradication: A prospective, open-label, randomized trial

BACKGROUND AND STUDY AIMS

The present study was designed to evaluate the safety, efficacy, and tolerability of antofloxacin-based bismuth quadruple therapy in Chinese patients with Helicobacter pylori infection.

PATIENTS AND METHODS

Total 290 patients with H. pylori infection were randomly and equally divided into two groups as per different bismuth quadruple therapies for 14 d: colloidal bismuth pectin 200 mg thrice a day, lansoprazole 30 mg twice a day, amoxicillin 1 g twice a day, and antofloxacin 200 mg once a day (ACLA group) or levofloxacin 500 mg once a day (LCLA group). Eradication was assessed with ¹³C-urea breath test 6 wk after treatment completion; the primary endpoint was the eradication rate by intention-to-treat (ITT) and per-protocol (PP) analyses. The minimum inhibitory concentration was measured with the PDM epsilometer test to assess the susceptibility of H. pylori strains on gastric biopsy specimens to antofloxacin and levofloxacin.

RESULTS

The eradication rates of H. pylori in the ACLA group were 93.8% and 97.8% for the ITT and PP analysis, respectively; these rates were significantly higher than those in the LCLA group, at 86.2% and 92.6%, respectively (p = 0.031 and 0.041, respectively). The total incidence of adverse events during the eradication therapy did not significantly differ between the ACLA and LCLA groups (31.7% vs. 37.9%%, p = 0.267), and the two groups displayed similar severity of adverse events (p = 0.156) and compliance rate (100% by ACLA vs. 97.8% by LCLA, p = 0.080). The eradication rate with the antofloxacin susceptible strains in the ACLA group was significantly higher than that with the resistant strains (99.2% vs. 66.7%, p = 0.045). Moreover, the eradication rate with the levofloxacin susceptible strains in the LCLA group was significantly higher than that with the resistant strains (95.3% vs. 80.0%, p = 0.013).

CONCLUSION

Antofloxacin is safe and effective for H. pylori eradication. Antofloxacin-based bismuth quadruple therapy could be an alternative treatment for H. pylori eradication.

The appropriate cutoff gastric pH value for Helicobacter pylori eradication with bismuth-based quadruple therapy

BACKGROUND

This study aimed to investigate whether an increased proton pump inhibitor (PPI) dose enhanced the efficacy of Helicobacter pylori (H. pylori) eradication and determine the appropriate cutoff intragastric pH value that could predict H. pylori eradication with bismuth-based quadruple therapy.

MATERIALS AND METHODS

A total of 207 H. pylori infected, treatment naive patients were enrolled in this prospective, open-label, randomized controlled trial. Patients were randomly allocated into Eso40-group (esomeprazole 40 mg bid) and Eso20-group (esomeprazole 20 mg bid), and their CYP2C19 genotyping status was assessed. The 24-h intragastric pH monitoring on day 7 was performed, and percentage of time gastric pH ≥ 3, ≥4, ≥5, and ≥6 (pH holding time ratios; HTRs) were measured. H. pylori eradication was evaluated using ¹³ C-urea breath test.

RESULTS

No significant difference in the eradication rates was observed between two groups. The median 24-h intragastric pH value was not significant different between two groups but the Eso40 Group had a significant higher pH4 HTRs (91.11% [95%CI: 87.50%-95.83%] vs. 95.83% [95.83%-100%]; p = .002). Additionally, the median 24-h intragastric pH value showed significantly difference between two groups in EM genotype (Eso20 Group 6.00 [95%CI; 5.75-6.15] vs. Eso40 Group 6.30 [6.05-6.30]; p = .019). Similar results were observed in pH4 HTRs. There were significant differences in intragastric pH value (6.10 [95%CI: 4.40-7.00] vs. 5.65 [4.85-5.95], p = .038) and in pH4 HTRs (96% [95%CI: 92.00%-96.00%] vs. 87.5% [67.00%-100.0%], p = .019) between eradication-successful and eradication-failed patients. Statistical analysis suggested that the median intragastric pH = 5.7 could identify the success of H. pylori eradication.

CONCLUSIONS

Bismuth-based quadruple therapy resulted in high H. pylori eradication rates either in PPI standard or double doses. Double dose of esomeprazole is associated with better intragastric acid suppression. A median 24-h intragastric pH of 5.7 could be appropriate cutoff value for predicting the successful H. pylori eradication.

Dual Clarithromycin and Metronidazole Resistance Is the Main Cause of Failure in Ultimate Helicobacter pylori Eradication

BACKGROUND/AIM

Antimicrobial resistance significantly affects the cure rate of Helicobacter pylori (H. pylori) eradication. We evaluated the risk factor of failure in ultimate H. pylori eradication and assessed the efficacy of current regimens to overcome antibiotic resistance.

METHODS

Patients with H. pylori infection were prospectively enrolled in a single center. They were classified into 3 groups according to the previous history of H. pylori eradication, and antibiotic susceptibility was evaluated by culture and minimum inhibitory concentrations (MICs).

RESULTS

Ninety-seven patients were successfully cultured for H. pylori and 81 (83.5%), 7 (7.2%), and 9 (9.3%) were classified into primary resistance, 1st eradication failure, and 2nd or more eradication failure groups; the resistance to clarithromycin (CLA), metronidazole (MET), and levofloxacin increased in the 1st eradication failure (85.7, 57.1, and 42.9%) and 2nd or more eradication failure (88.9, 88.9, and 55.6%) groups. The prevalence of MDR was 21.0% (17/81), 57.1% (4/7), and 88.9% (8/9) in the primary, 1st eradication failure, and 2nd or more eradication failure groups, respectively. In multivariate analysis, dual CLA/MET resistance (CLA/MET-R) (OR = 31.432, 95% CI: 3.094-319.266, p = 0.004) was an independent risk factor for ultimate H. pylori eradication failure. In patients with dual CLA/MET-R, the eradication ratio of concomitant therapy was 57.1% (4/7), whereas that of bismuth-containing quadruple therapy was 27.3% (3/11) (p = 0.350).

CONCLUSIONS

Dual CLA/MET-R was the main cause of failure in ultimate H. pylori eradication, and 7-day bismuth quadruple or concomitant regimen would not be suitable for H. pylori eradication in the dual CLA/MET-R group.

High-dose dual therapy versus bismuth-containing quadruple therapy for the treatment of Helicobacter pylori infection – A review of the strengths, weaknesses, and proposed solutions

Helicobacter pylori is the principal cause of peptic ulcers, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. The first treatment to H. pylori infection is dual therapy (a bismuth compound plus metronidazole). On the launch of omeprazole in 1988, dual therapy became omeprazole and amoxicillin (low dose). The poor H. pylori eradication rates by either bismuth-based or low-dose dual therapy drove more combinations of antibiotics were needed. Antibiotic resistance, especially clarithromycin and metronidazole, has made bismuth-containing quadruple therapy (BCQT) a savior for first-line and second-line treatments. However, its complicated dosing regimen commonly causes more adverse events and poor drug compliance. Thus, high-dose dual therapy (HDDT) has been re-arising. This article reviews the strengths and weaknesses of HDDT versus BCQT with proposed solutions.

Amoxicillin or tetracycline in bismuth-containing quadruple therapy as first-line treatment for Helicobacter pylori infection

AIM

To compare the efficacy and safety between modified quadruple- and bismuth-containing quadruple therapy as first-line eradication regimen for Helicobacter pylori infection.

METHODS

This study was a multicenter, randomized-controlled, non-inferiority trial. Subjects endoscopically diagnosed with H. pylori infection were randomly allocated to receive modified quadruple- (rabeprazole 20 mg bid, amoxicillin 1 g bid, metronidazole 500 mg tid, bismuth subcitrate 300 mg qid [elemental bismuth 480 mg]; PAMB) or bismuth-containing quadruple therapy (rabeprazole 20 mg bid, bismuth subcitrate 300 mg qid, metronidazole 500 mg tid, tetracycline 500 mg qid; PBMT) for 14 days. Rates of eradication success and adverse events were investigated. Antibiotic resistance was determined using the agar dilution and DNA sequencing of the clarithromycin resistance point mutations in the 23 S rRNA gene of H. pylori.

RESULTS

In total, 233 participants were randomized, 27 were lost to follow-up, and four violated the protocol. Both regimens showed an acceptable eradication rate in the intention-to-treat (PAMB: 87.2% vs. PBMT: 82.8%, P = .37), modified intention-to-treat (96.2% vs. 96%, P > .99), and per-protocol (96.2% vs. 96.9%, P > .99) analyses. Non-inferiority in the eradication success between PAMB and PBMT was confirmed. The amoxicillin-, metronidazole-, tetracycline-, clarithromycin-, and levofloxacin-resistance rates were 8.3, 40, 9.4, 23.5, and 42.2%, respectively. Antimicrobial resistance did not significantly affect the efficacy of either therapy. Overall compliance was 98.1%. Adverse events were not significantly different between the two therapies.

CONCLUSION

Modified quadruple therapy comprising rabeprazole, amoxicillin, metronidazole, and bismuth is an effective first-line treatment for the H. pylori infection in regions with high clarithromycin and metronidazole resistance.

Annual eradication rate of bismuth-containing quadruple therapy as second-line treatment for Helicobacter pylori infection: A 15-year prospective study at a tertiary hospital in Korea

BACKGROUND

Bismuth-containing quadruple therapy is widely used as second-line treatment for Helicobacter pylori infection. This prospective study investigated the changes in the annual H. pylori eradication rates of quadruple therapy.

METHODS

This study included an intention-to-treat (ITT) population of 452 subjects who failed first-line eradication therapy for H. pylori between 2003 and 2018. All subjects received a 14-day course of bismuth-containing quadruple therapy consisting of esomeprazole (40 mg twice daily), metronidazole (500 mg thrice daily), bismuth subcitrate (120 mg four times daily), and tetracycline (500 mg four times daily). Per-protocol (PP) analysis of data was performed in subjects who followed up with strict treatment adherence. Eradication was confirmed based on the results of the ¹³ C-urea breath test, rapid urease test (CLOtest^® ), and histopathologic evaluation. Compliance and adverse effects were also investigated. A minimal inhibitory concentration test was performed on tissue samples obtained from 103 subjects.

RESULTS

The overall eradication rates following ITT and PP analyses were 78.8% (356/452) and 89.5% (314/351), respectively. The annual eradication success rate did not show significant changes (P = .062 [ITT], P = .857 [PP]) over the 15-year study period. Adverse events were reported in 57.3% of the ITT population. The rates of resistance to metronidazole and tetracycline were 44.7% and 18.4%, respectively.

CONCLUSIONS

Despite high antibiotic resistance rates, no significant reduction in annual eradication rates was observed during the study period.

High-dose PPI-amoxicillin dual therapy with or without bismuth for first-line Helicobacter pylori therapy: A randomized trial

BACKGROUND

A reliably highly effective high-dose proton-pump inhibitor plus amoxicillin (dual Helicobacter pylori therapy) has remained elusive. We compared whether the addition of bismuth to high-dose dual therapy would improve the efficacy of high-dose dual therapy as first-line treatment.

METHODS

This was an open-label, randomized single-center study of 160 treatment-naive patients with H. pylori infection who were randomly assigned to 14-day therapy with esomeprazole 40 mg twice a day plus amoxicillin 1 g three times a day with or without bismuth potassium citrate 600 mg (elemental bismuth 220 mg) twice a day. Antibiotic resistance was determined by agar dilution method and eradication by ¹³ C-urea breath test.

RESULTS

The per-protocol eradication rates were 96.1%; 95% CI = 88.9%-99.2% (73/76) without bismuth vs 93.3%; 95% CI = 85.1%-97.8% (70/75) with bismuth (P = 0.494). The intention-to-treat eradication rates were 92.5%; 95% CI = 84.4%-97.2% (74/80) without bismuth and 88.8%; 95% CI = 79.7%-94.7% (71/80) with bismuth (P = 0.416). Resistance to amoxicillin, clarithromycin, metronidazole, and levofloxacin was 0%, 31.7%, 81.4%, and 40.7%, respectively. Smoking reduced treatment effectiveness limited to those not receiving bismuth. The per-protocol eradication rates were 70% (7/10) vs 100% (66/66) in smokers vs non-smokers without bismuth (P = 0.002), and 100% (10/10) in smokers vs 92.3% (60/65) in non-smokers with bismuth (P = 1.0). The adverse event rates were 7.5% (6/80) without bismuth vs 11.3% (9/80) with bismuth (P = 0.416).

CONCLUSIONS

Fourteen-day high-dose dual therapy was both effective and safe for first-line treatment in a region of high prevalence antibiotic resistance. Adding bismuth only improved treatment effectiveness among smokers.

Cefuroxime, levofloxacin, esomeprazole, and bismuth as first-line therapy for eradicating Helicobacter pylori in patients allergic to penicillin

Background

Eradicating Helicobacter pylori infection is clinically challenging, notably in cases with penicillin allergy. Cephalosporin could be used in lieu of amoxicillin to eradicate Helicobacter pylori. The current work aimed to assess therapeutic efficacy and safety of a cefuroxime-based quadruple regimen in treatment-naïve individuals with penicillin allergy, as well as patient compliance.

Methods

In the present prospective single-center cohort study, 152 Helicobacter pylori infected individuals with penicillin allergy received eradication therapy with cefuroxime (500 mg twice/day), levofloxacin (500 mg once/day), esomeprazole (20 mg twice/day) and bismuth potassium citrate (220 mg twice/day; 14 days). Safety and compliance were evaluated 1 to 3 days upon eradication. The urea breath test was carried out 8 to 12 weeks upon eradication for efficacy assessment.

Results

This quadruple antimicrobial regimen eradicated the pathogen at 85.5% (95% confidence interval (CI) 79.6–90.8%), 88.4% (95% CI 83.0–93.2%) and 90.1% (95% CI 85.2–94.4%) in intention-to-treat, modified intention-to-treat and per-protocol analyses, respectively, with resistance rates of 4.6 and 40.0% in the background of cefuroxime and levofloxacin, respectively. Meanwhile, 21.3% of patients had adverse reactions, but none was serious. A total of 95.3% of patients showed good compliance. Poor compliance and cefuroxime resistance were detected by uni- or multivariate analyses as independent factors predicting therapeutic failure. Eradication rates in patients with dual levofloxacin and cefuroxime susceptibility, isolated levofloxacin resistance, isolated cefuroxime resistance and dual resistance were 97.2, 84.0, 50.0, and 0%, respectively (P = 0.002).

Conclusions

Cefuroxime, levofloxacin, esomeprazole, and bismuth achieved decent efficacy, safety and compliance as first-line antimicrobial regimen in patients with Helicobacter pylori and penicillin allergy.

Initial Trials With Susceptibility-Based and Empiric Anti-H. pylori Therapies in Mongolia

Background: Mongolia has a high prevalence of Helicobacter pylori infection and gastric cancer. We conducted a prospective, randomized, single-blind study to evaluate the efficacy of common regimens in Mongolia and to obtain specimens for susceptibility testing. Methods: Empiric treatments: 270 patients with confirmed H. pylori infection were randomized to receive 10 days clarithromycin-triple therapy (Clari-TT) (n = 90), modified bismuth quadruple therapy (M-BQT) (n = 90), or sequential therapy (ST) (n = 90). A second group of 46 patients received susceptibility-based Clari-TT. H. pylori was cultured from 131 patients and susceptibility testing was performed. H. pylori eradication was confirmed by stool antigen 4 weeks after the therapy. Results: Intention-to-treat (ITT) analysis cure rates were 71.1% (95% CI = 61.7-80.5%) for Clari-TT, 87.8% (95% CI = 81-94.6%) for M-BQT, 67.8% (95% CI = 58.1-77.5%) for ST vs. 89.1% (95% CI = 86-98.2%) for susceptibility-based Clari-TT. Per-protocol (PP) analysis results for these therapies were 72.7% (63.4-82%), 89.8% (83.5-96.1%), 68.5% (58.8-78.2%), and 97.6% (89.5-99.8%), respectively. Among 131 cultured H. pylori, resistance rates to amoxicillin, clarithromycin, and metronidazole were 8.4, 37.4, and 74%, respectively. Conclusion: In Mongolia, the prevalence of H. pylori resistance is high requiring bismuth quadruple therapy or susceptibility-based therapy to obtain acceptable cure rates.

Risk factors of rescue bismuth quadruple therapy failure for Helicobacter pylori eradication

BACKGROUND AND AIM

Failure of bismuth quadruple therapy for Helicobacter pylori eradication is frequently observed. To increase the eradication rate, comprehensive analyses need to be performed regarding risk factors of bismuth quadruple therapy failure based on complete standard culture and antimicrobial susceptibility testing results.

METHODS

Patients with history of failed first therapy who had H. pylori colonies isolated from culture and successful minimum inhibitory concentration (MIC) test were enrolled. Esomeprazole, bismuth, metronidazole, and tetracycline (quadruple) therapies for 7 or 14 days were given. Eradication rate, treatment compliance, adverse events, and risk factors for the failure of bismuth quadruple therapy were analyzed.

RESULTS

A total 54 patients were enrolled. Overall eradication rate in the present study was 88.8%. The eradication rate for cases with metronidazole resistance such as MIC 8-16 μg/mL or 16-32 μg/mL was 92.8% (13/14). For cases with high level metronidazole resistance (MIC > 32 μg/mL), the eradication rate was only 60% (6/10). Multivariate analysis regarding compliance, treatment duration, age > 60, three kinds of metronidazole MICs, tetracycline MIC > 4 μg/mL, adverse events and any other parameters, "metronidazole resistance, high level (MIC > 32 μg/mL)" was the only independent risk factor for eradication failure (P = 0.007).

CONCLUSION

For cases with metronidazole resistance at MIC > 32 μg/mL, rescue therapy other than bismuth-containing quadruple therapy is needed.

Multi-omics and temporal dynamics profiling reveal disruption of central metabolism in Helicobacter pylori on bismuth treatment

Integration of multi-omics enables uncovering cellular responses to stimuli or the mechanism of action of a drug at a system level. Bismuth drugs have long been used for the treatment of Helicobacter pylori infection and their antimicrobial activity was attributed to dysfunction of multiple proteins based on previous proteome-wide studies. Herein, we investigated the response of H. pylori to a bismuth drug at transcriptome and metabolome levels. Our multi-omics data together with bioassays comprehensively reveal the impact of bismuth on a diverse array of intracellular pathways, in particular, disruption of central carbon metabolism is systematically evaluated as a primary bismuth-targeting system in H. pylori. Through temporal dynamics profiling, we demonstrate that bismuth initially perturbs the TCA cycle and then urease activity, followed by the induction of oxidative stress and inhibition of energy production, and in the meantime, induces extensive down-regulation in H. pylori metabolome. The present study thus expands our knowledge on the inhibitory actions of bismuth and provides a novel systematic perspective of H. pylori in response to a clinical drug that sheds light on enhanced therapeutic methodologies.

The protective role of autophagy in nephrotoxicity induced by bismuth nanoparticles through AMPK/mTOR pathway

Bismuth is widely used in metallurgy, cosmetic industry, and medical diagnosis and recently, bismuth nanoparticles (NPs) (BiNP) have been made and proved to be excellent CT imaging agents. Previously, we have synthesized bovine serum albumin based BiNP for imaging purpose but we found a temporary kidney injury by BiNP. Due to the reported adverse events of bismuth on human health, we extended our studies on the mechanisms for BiNP induced nephrotoxicity. Blood biochemical analysis indicated the increase in creatinine (CREA) and blood urea nitrogen (BUN), and intraluminal cast formation with cell apoptosis/necrosis was evident in proximal convoluted tubules (PCTs) of mice. BiNP induced acute kidney injury (AKI) was associated with an increase in LC3II, while the autophagic flux indicator p62 remained unchanged. Chloroquine and rapamycin were used to evaluate the role of autophagy in AKI caused by BiNP. Results showed that BiNP induced AKI was further attenuated by rapamycin, while AKI became severe when chloroquine was applied. In vitro studies further proved BiNP induced autophagy in human embryonic kidney cells 293, presented as autophagic vacuole (AV) formation along with increased levels of autophagy-related proteins including LC3II, Beclin1, and Atg12. Specifically, reactive oxygen species (ROS) generated by BiNP could be the major inducer of autophagy, because ROS blockage attenuated autophagy. Autophagy induced by BiNP was primarily regulated by AMPK/mTOR signal pathway and partially regulated by Akt/mTOR. Our study provides fundamental theory to better understand bismuth induced nephrotoxicity for better clinical application of bismuth related compounds.

Exposure and nephrotoxicity concern of bismuth with the occurrence of autophagy

Metal nanoparticles or metal-based compounds have drawn attention in various fields ranging from industry to medicine because of their unique physicochemical properties. Bismuth (Bi) compounds and nanomaterials have been commonly used in alloys, electronic industry, batteries, and as flame retardants as well as for anti- Helicobacter pylori therapy, while the nanomaterial form has great potential for computed tomography imaging and thermotherapy, both of which will be introduced in this review. Although Bi was used for several decades, there is a lack of detailed information concerning their toxicity and mechanisms on human health. We described the toxicity of Bi on the kidney that seemed to be relatively known by researchers, while the mechanisms remain unclear. Recently, our group has found that Bi compounds, including bismuth nitrate (BN) and Bi nanomaterials, can induce autophagy in kidney cells. We also extended our findings by selecting five Bi compounds, and the results showed that BN, bismuth oxychloride, bismuth citrate, colloidal bismuth subcitrate, and Bi nanomaterials all induced slight cytotoxicity accompanied with autophagy. Although the role of autophagy in Bi-induced cytotoxicity and kidney injury is under investigation by us, autophagy may help with the exploration of the mechanisms of nephrotoxicity by Bi.

Efficacy and Safety of Wei Bi Mei, a Chinese Herb Compound, as an Alternative to Bismuth for Eradication of Helicobacter pylori

Bismuth-containing quadruple therapy has been recommended as the first line of treatment in areas of high clarithromycin or metronidazole resistance. However, safety concerns of bismuth agents have long been raised. We first assessed the efficacy and safety of Wei Bi Mei granules, which are bismuth compounds consisting of three synthetic drugs and five medicinal herbs, compared to bismuth aluminate and colloidal bismuth subcitrate (CBS) in H. pylori-infected mouse model. We then used atomic fluorescence spectroscopy and autometallography to measure the accumulation of three bismuth agents in the brain, heart, liver, and kidneys in adult Sprague-Dawley rats. We also evaluated the safety of bismuth agents by conducting clinical biochemistry tests in blood samples of experimental animals. Wei Bi Mei granules exhibited the highest efficacy of anti-H. pylori activity and yielded the lowest bismuth accumulation when compared to CBS and bismuth aluminate. Our findings show that Wei Bi Mei granules are a safe Chinese medicinal herb with potent anti-H. pylori activity and can be considered as an alternative to current bismuth compounds. Thus, Wei Bi Mei granules merit further evaluation, particularly with regard to efficacy and safety when they are combined with other H. pylori eradication medications in the clinical setting.

Randomized Clinical Trial: Esomeprazole, Bismuth, Levofloxacin, and Amoxicillin or Cefuroxime as First-Line Eradication Regimens for Helicobacter pylori Infection

BACKGROUND

The eradication of Helicobacter pylori infection remains a challenge, especially in the patients unsuitable to take penicillin. Cephalosporin has the potential to replace amoxicillin for H. pylori eradication.

AIMS

To compare the effectiveness, safety, and compliance of amoxicillin- and cefuroxime-containing quadruple regimens in treatment-naïve patients.

METHODS

In this open-label randomized control study, 400 patients with H. pylori infection were divided into amoxicillin-containing (esomeprazole 20 mg twice/day, amoxicillin 1000 mg twice/day, levofloxacin 500 mg once/day, and bismuth 220 mg twice/day for 14 days) or cefuroxime-containing (esomeprazole 20 mg twice/day, cefuroxime 500 mg twice/day, levofloxacin 500 mg once/day, and bismuth 220 mg twice/day for 14 days) quadruple therapy groups. The safety and compliance were assessed 1-3 days after eradication. Urea breath test was performed 8-12 weeks after eradication to determine treatment outcome.

RESULTS

The baseline data including antibiotic resistance were well matched between the two groups. The eradication rates between amoxicillin- and cefuroxime-containing quadruple therapy groups were not significantly different [intention-to-treat analysis: 83.5% (95% confidence interval 78.3-88.7%) vs. 81.0% (75.5-86.5%), P = 0.513; modified intention-to-treat analysis: 90.3% (86.0-94.6%) vs. 88.5% (83.9-93.2%), P = 0.586; per-protocol analysis: 91.6% (87.5-95.7%) vs. 89.8% (85.3-94.3%), P = 0.560]. The incidence of adverse effects (18.4 vs. 20.1%, P = 0.678) and compliance (94.7 vs. 94.2%, P = 0.813) were also similar. Variate analyses showed that antibiotic resistance and poor compliance were the independent risk factors for eradication failure.

CONCLUSIONS

Esomeprazole, bismuth, levofloxacin, and amoxicillin or cefuroxime achieved similar and relatively satisfactory cure rates, safety, and compliance in first-line H. pylori eradication. Cefuroxime may be a good alternative medicine for eradication instead of amoxicillin for the patients unsuitable to take penicillin.

Autophagy associated cytotoxicity and cellular uptake mechanisms of bismuth nanoparticles in human kidney cells

Bismuth compounds have been used for treatment of bacterial infection, and recently bismuth nanoparticles (BiNP) were synthesized for imaging and diagnostic purpose, while safety concern of bismuth cannot be ignored. Here, we prepared ultrasmall BiNP and showed an enhanced tumor imaging, but BiNP revealed a differentiated cytotoxicity in human embryonic kidney 293 cells (HEK293) compared to other cell types. For the first time, we found that BiNP can induce autophagy, shown as the increase of monodansylcadaverine fluorescence staining and the amount of LC3II that can be inhibited by 3-MA. BiNP were capable of entering cells in a dose and time dependent manner by fluorescence and element detection methods BiNP were found to be localized in the cytoplasm observed by transmission electron microscopy and intracellular bismuth element confirmed by energy dispersive X-ray analysis. Using endocytic inhibitors, BiNP were found to require ATP and endosomal trafficking pathways for their cellular uptake. Internalized BiNP did not co-localize with EEA1, but co-localized with Lysotracker/LAMP1/LAMP2 at late time points, indicating BiNP may be retained in the non-early endosomal vacuoles and late endosomes. With our novel finding of bismuth induced autophagy and endocytic mechanisms, potential approaches may be applied to reduce the toxicity by bismuth.

Current status of Helicobacter pylori infection and evolution of treatment strategy in China

Infection with Helicobacter pylori (H. pylori) has become a common digestive disease and the prevalence of H. pylori infection remains high in the Chinese population. Recently, the Kyoto global consensus report on H. pylori gastritis and the Toronto consensus for the treatment of H. pylori infection in adults were issued. Therefore, it is essential to discuss the prevention and control of H. pylori infection in China. Due to severe resistance to antibiotics, toxic and host factors, the eradication rate in China has currently became lower than before. Therefore, whether to intervene H. pylori infection in the asymptomatic population and enlarge the indication for eradication and the cost-effect for this new strategy should be discussed. In addition, the implementation of the "test and treat" policy or not in China is debatable. Developing optimal treatment strategy has become a major challenge that clinicians face. This review focuses on the current H. pylori infection situation and the evolution of treatment strategies in China.

Treatment of Helicobacter pylori infection 2016

Many interesting articles have been published from different parts of the world over the last year assessing various issues around Helicobacter pylori eradication therapy. This article will address the published literature over the last year pertaining to the topic of treatment of H. pylori infection. The main themes that emerge are assessing the efficacy of standard triple therapy, as well as exploring new first-line treatments, mainly optimized nonbismuth-containing and bismuth-containing quadruple therapies with some promising data also emerging on dual therapy. There was also considerable progress in investigating antibiotic resistance rates with much more data emerging from varied parts of the world compared to recent years. Advances in the use of adjunctive therapies, especially probiotic therapies have also been made. Undoubtedly, the eradication of H. pylori remains a worthwhile goal to alleviate the burden of diseases caused by the complications of this infection, including dyspepsia, peptic ulcer disease, and gastric cancer.

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.

Role of bismuth in improving Helicobacter pylori eradication with triple therapy

In most regions of the world, antimicrobial resistance has increased to the point where empirical standard triple therapy for Helicobacter pylorieradication is no longer recommended. The treatment outcome in a population is calculated as the sum of the treatment success in the subpopulation with susceptible infections plus treatment success in the subpopulation with resistant infections. The addition of bismuth (i.e., 14-day triple therapy plus bismuth) can improve cure rates despite a high prevalence of antimicrobial resistance. The major bismuth effect is to add an additional 30%-40% to the success with resistant infections. The overall result is therefore dependent on the prevalence of resistance and the treatment success in the subpopulation with resistant infections (eg, with proton-pump inhibitor-amoxicillin dual therapy). Here, we explore the contribution of each component and the mechanisms of how bismuth might enhance the effectiveness of triple therapy. We also discuss the limitations of this approach and provide suggestions how triple therapy plus bismuth might be further improved.