Isolation of Helicobacter pylori using leftover tissue in the rapid urease test kit

Helicobacter pylori Antimicrobial Susceptibility Testing-Guided Eradication Therapy in the Southeast Region of China: A Retrospective Study

Background and Aim

Antibiotic resistance of Helicobacter pylori is increasing worldwide, lowering its efficacy in eradication therapy and posing a serious threat to human health. This study evaluated H. pylori resistance to antibiotics in the southeast region of China and explored factors related to eradication failure guided by antimicrobial susceptibility testing (AST).

Methods

In this retrospective study, patients who tested positive underwent gastroscopy, and H. pylori infection was confirmed by histological staining and H. pylori culture. We determined the rate of H. pylori antibiotic resistance, success rate of AST-guided eradication therapy, and risk factors associated with treatment failure.

Results

Among the 210 enrolled patients, 188 (89.5%) had successful cultures, and 183 (87.1%) underwent AST. The most common antibiotic resistance was to metronidazole and clarithromycin (89.6%), followed by levofloxacin (68.3%), and amoxicillin (14.2%). Furazolidone (3.0%) and tetracycline (0.5%) showed relatively low resistance rates. There were no statistically significant differences in the rates of resistance to MET, LEV, or AMX between naive and non-naive patients. However, CLA resistance rates in non-naive patients were significantly higher than those in naive patients. The overall success rate of AST-guided therapy was high and showed no significant difference between first-line and rescue therapy. Sex, age, prior therapy, and proton pump inhibitors (PPIs) or potassium-competitive acid blockers (P-CABs) use were not significantly associated with an increased risk of eradication failure in AST-guided therapy.

In Vitro Susceptibility and Synergistic Effect of Bismuth Against Helicobacter pylori

Background/objectives: Bismuth is commonly used in Helicobacter pylori (H. pylori) eradication therapy. However, few studies have examined the in vitro susceptibility of H. pylori to bismuth. Moreover, the exact mechanism of action of bismuth on H. pylori remains unclear. The aim of this study was to identify the anti-bacterial effect of bismuth as well as to evaluate potential synergistic effects between bismuth and various antibiotics. Methods: The minimum inhibitory concentrations (MICs) of three bismuth preparations, bismuth subsalicylate, bismuth potassium citrate, and colloidal bismuth subcitrate (CBS, De-Nol) were determined for H. pylori strains using the agar dilution technique. Agar plates of varying pH values from 5.0 to 8.0 were used to investigate whether acidity influences the anti-bacterial effect of bismuth. A checkerboard assay was performed to assess the synergism between CBS and antibiotics (amoxicillin, clarithromycin, and metronidazole). Results: Twelve H. pylori strains, including three reference strains (H. pylori 26695, J99, and ATCC 43504), and nine clinically isolated strains were tested. The MICs for bismuth subsalicylate, bismuth potassium citrate, and CBS ranged from 4 to 32 μg/mL, 2 to 16 μg/mL, and 1 to 8 μg/mL, respectively. The bismuth MICs for the reference strains were similar at pH 5-8. In the checkerboard assay, no interactions between CBS and any of the antibiotics were observed in the reference H. pylori strains. Conclusions: Bismuth showed in vitro susceptibility against H. pylori. The enhanced eradication efficacy of bismuth-containing regimens appears to be due to mechanisms other than direct synergy with antibiotics.

Helicobacter pylori Infection, Its Laboratory Diagnosis, and Antimicrobial Resistance: a Perspective of Clinical Relevance

Despite the recent decrease in overall prevalence of Helicobacter pylori infection, morbidity and mortality rates associated with gastric cancer remain high. The antimicrobial resistance developments and treatment failure are fueling the global burden of H. pylori-associated gastric complications. Accurate diagnosis remains the opening move for treatment and eradication of infections caused by microorganisms. Although several reports have been published on diagnostic approaches for H. pylori infection, most lack the data regarding diagnosis from a clinical perspective. Therefore, we provide an intensive, comprehensive, and updated description of the currently available diagnostic methods that can help clinicians, infection diagnosis professionals, and H. pylori researchers working on infection epidemiology to broaden their understanding and to select appropriate diagnostic methods. We also emphasize appropriate diagnostic approaches based on clinical settings (either clinical diagnosis or mass screening), patient factors (either age or other predisposing factors), and clinical factors (either upper gastrointestinal bleeding or partial gastrectomy) and appropriate methods to be considered for evaluating eradication efficacy. Furthermore, to cope with the increasing trend of antimicrobial resistance, a better understanding of its emergence and current diagnostic approaches for resistance detection remain inevitable.