Tailored therapy guided by genotypic resistance of clarithromycin and levofloxacin detected by polymerase chain reaction in the first-line treatment of Helicobacter pylori infection.

OBJECTIVES: We aimed to explore the efficacy and safety of tailored therapy guided by genotypic resistance in the first-line treatment of Helicobacter pylori (H. pylori) infection in treatment-naive patients. METHODS: Gastric mucosal specimens were taken during gastroscopy, and main mutations of clarithromycin- and levofloxacin-resistant genes were detected by polymerase chain reaction (PCR). Sensitive antibiotics were selected individually for treating H. pylori infection with tailored bismuth-containing quadruple therapy (BQT) consisting of esomeprazole 20 mg twice daily, bismuth potassium citrate 220 mg twice daily, amoxicillin 1 g twice daily, and clarithromycin 500 mg twice daily, or levofloxacin 500 mg once daily, or metronidazole 400 mg four times daily. Safety and patient compliance were assessed 1-3 days after eradication. Treatment outcome was evaluated by urea breath test 4-8 weeks after eradication. RESULTS: One hundred and thirty-two treatment-naive patients with H. pylori infection were included. PCR results suggested resistance rates of 47.7% and 34.9% for clarithromycin and levofloxacin, respectively, and a dual resistance rate of 18.2%. Eradication rates of tailored BQT were 87.1% and 95.8% by intention-to-treat (ITT) analysis and per-protocol (PP) analysis, respectively. There was no statistically significant difference in the efficacy of 7-day clarithromycin-containing, 7-day levofloxacin-containing, and 14-day full-dose metronidazole-containing BQT (ITT analysis: P = 0.488; PP analysis: P = 0.833). The incidence of adverse events was 19.7%, and patient compliance was 97.7%. CONCLUSION: Tailored BQT guided by genotypic resistance can achieve satisfactory efficacy, safety, and patient compliance in the first-line treatment of H. pylori infection.

[Comparison of Epsilometer test and agar dilution method in detecting the sensitivity of Helicobacter pylori to metronidazole].

OBJECTIVE: Agar dilution method (ADM) was used as the golden standard to evaluate the consistency of Epsilometer test (E-test) in detecting the sensitivity of Helicobacter pylori (H. pylori) to metronidazole. METHODS: From August 2018 to July 2020, patients with H. pylori infection treated for the first time in Peking University Third Hospital for gastroscopy due to dyspepsia were included in this study. Gastric mucosas were taken from the patients with H. pylori infection. H. pylori culture was performed. Both the ADM and E-test were applied to the antibiotic susceptibility of H. pylori to metro-nidazole, and the consistency and correlation between the two methods were validated. RESULTS: In the study, 105 clinical isolates of H. pylori were successfully cultured, and the minimum inhibitory concentration ≥ 8 mg/L was defined as drug resistance. Both ADM and the E-test showed high resistance rates to metronidazole, 64.8% and 62.9%, respectively. Among them, 66 drug-resistant strains were detected by ADM and E-test, and 37 were sensitive strains, so the consistency rate was 98.1%. Two strains were evaluated as drug resistance by ADM, but sensitive by the E-test, with a very major error rate of 1.9%. There was zero strain sensitive according to ADM but assessed as resistant by the E-test, so the major error rate was 0%. Taking ADM as the gold standard, the sensitivity of E-test in the detection of metronidazole susceptibility was 97.1% (95%CI: 0.888-0.995), and the specificity was 100% (95%CI: 0.883-1.000). Cohen's kappa analysis showed substantial agreement, and kappa coefficient was 0.959 (95%CI: 0.902-1.016, P < 0.001). Spearmans correlation analysis confirmed this correlation was significant (r=0.807, P < 0.001). The consistency evaluation of Bland-Altman method indicated that it was good, and there was no measured value outside the consistency interval. In this study, cost analysis, including materials and labor, showed a 32.2% higher cost per analyte for ADM as compared with the E-test (356.6 yuan vs. 269.8 yuan). CONCLUSION: The susceptibility test of H. pylori to metronidazole by E-test presents better agreement with ADM. Because it is less expensive, less labor intensive, and more rapid, it is an easy and reliable method for H. pylori susceptibility testing.

Bismuth, esomeprazole, metronidazole and amoxicillin or tetracycline as a first-line regimen for Helicobacter pylori eradication: A randomized controlled trial.

BACKGROUND: Due to general unavailability and common side effects of tetracycline, the clinical application of bismuth quadruple therapy (BQT) is greatly limited. Whether amoxicillin can replace tetracycline in BQT remains unknown. This study aimed to compare the eradication rate, safety and compliance between amoxicillin-containing and tetracycline-containing BQT as a first-line regimen for Helicobacter pylori eradication. METHODS: This randomized trial was conducted on 404 naïve patients for H. pylori eradication. The participants were randomly assigned to 14-day amoxicillin-containing (bismuth potassium citrate 110 mg four times/day, esomeprazole 20 mg twice daily, metronidazole 400 mg four times/day and amoxicillin 500 mg four times/day) and tetracycline-containing (tetracycline 500 mg four times/day and the other three drugs used as above) BQT. Safety and compliance were assessed within 3 days after eradication. Urea breath test was performed 4-8 weeks after eradication to evaluate outcome. RESULTS: As for the eradication rates of amoxicillin-containing and tetracycline-containing BQT, the results of both intention-to-treat and per-protocol analyses showed that the difference rate of the lower limit of 95% confidence interval was above -10.0% (intention-to-treat analysis: 81.7% vs. 83.2%, with a rate difference of -1.5% [-6.3% to 9.3%]; per-protocol analysis: 89.0% vs. 91.6%, -2.6% [-4.1% to 9.3%]). The incidence of adverse events in amoxicillin-containing BQT was significantly lower than tetracycline-containing BQT (29.5% vs. 39.7%). Both groups achieved relatively good compliance (92.0% vs. 89.9%). CONCLUSION: The eradication efficacy of amoxicillin-containing BQT was non-inferior to tetracycline-containing BQT as a first-line regimen for H. pylori eradication with better safety and similar compliance.

[The effects of pronase on drugs concentrations for treatment of Helicobacter pylori infection in gastric tissue].

OBJECTIVE: To evaluate the effect of pronase on amoxicillin and metronidazole concentrations in gastric tissue. METHODS: C57BL/6 mice were randomly divided into experimental group (n = 70) and control group (n = 70). Amoxicillin (28.6 mg/kg), metronidazole (22.5 mg/kg) and omeprazole (138.2 mg/kg) were administered orally to C57BL/6 mice, combined with pronase (110 mg/kg) or same amount of sterile PBS. Gastric tissue and blood plasma samples were taken at 10 point-in-time (7 mice/time) from 15 min up to 360 min after administration. Concentrations of amoxicillin and metronidazole were detected by high performance liquid chromatography. Gastritis index of gastric mucosa (hematoxylin-eosin staining) and the gastric tissue expressions of mucin 5AC (Western blot) were detected at 120 min and 360 min after administration. RESULTS: The time to peak concentration of amoxicillin and metronidazole in gastric tissue appeared earlier than that in blood plasma (15 min vs 60 min). Tissue concentrations of amoxicillin and metronidazole of experimental group were significantly higher than those of control, and they were mainly at 15 min to 90 min (P < 0.05). Plasma concentrations of amoxicillin and metronidazole of experimental group at 15 min and 30 min were higher than those of control (P < 0.05). There was no difference in gastritis index between experimental group and control at 120 min and 360 min after administration (0.28 ± 0.18 vs 0.14 ± 0.14, P > 0.05; 0.43 ± 0.20 vs 0.28 ± 0.18, P > 0.05). The expressions of mucin 5AC in experimental group were lower than those of control (0.036 ± 0.006 vs 0.197 ± 0.058; P < 0.05; 0.039 ± 0.008 vs 0.208 ± 0.072, P < 0.05). CONCLUSIONS: Pronase can significantly enhance the drugs penetration from mucus into gastric tissue. Concentrations of amoxicillin and metronidazole of experimental group in local gastric tissue and plasma are higher than those of control, especially in improving concentrations of gastric tissue and prolongation of exposed time.