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Background: Metronidazole is a first‐line antibiotic to treat Helicobacter pylori infections. However, the Clinical Laboratory Standards Institute guidelines recommend against using antimicrobial susceptibility test (AST) to test metronidazole resistance, due to the unreliable predictive power which can result in treatment failure. Objectives: The aim of this study was to establish an 8‐h, metabolic‐phenotype based AST for H. pylori metronidazole susceptibility using D2O‐probed Raman microspectroscopy. Methods: Minimal inhibitory concentration (MIC) measured by conventional AST (E‐test) were compared with expedited MIC via metabolic activity (eMIC‐MA) for 10 H. pylori isolates. Raman barcodes of cellular‐response to stress (RBCS) incorporating protein and carbohydrate Raman bands, were utilized to identify a biomarker to distinguish metronidazole susceptibility. Results: Specifically, eMIC‐MA produces metronidazole susceptibility results showing 100% agreement with E‐test, and determines the bactericidal dosage for both high‐ and low‐level resistant H. pylori strains. In addition, RBCS not just reliably distinguish between metronidazole‐susceptible and ‐resistant strains, but reveal their distinct mechanisms in bacterial responses to metronidazole. Conclusion: The speed, accuracy, low cost, and rich information content that reveals the mode‐of‐action of drugs suggest the method's value in guiding metronidazole prescriptions for H. pylori eradication and in rapid screening based on drug‐resistance mechanism. [ABSTRACT FROM AUTHOR]

Background Hybrid therapy has recently attracted widespread attention. However, many issues require further exploration. For example, research in regions with high antibiotic resistance rates is limited, and the correlation between eradication efficacy and antibiotic resistance remains unclear. The aim of this study was to determine the efficacy, compliance, safety, and risk factors of hybrid therapy as first-line regimen in a region with high antibiotic resistance rates. Materials and Methods This prospective study was conducted in a tertiary hospital between January 2014 and June 2015. A total of 196 patients with dyspepsia but without prior eradication therapy received hybrid regimen (esomeprazole 20 mg and amoxicillin 1000 mg twice daily for 14 days with the addition of clarithromycin 500 mg and tinidazole 500 mg twice daily for the final 7 days). All patients underwent Helicobacter pylori culture, antibiotic susceptibility testing and cytochrome P450 isoenzyme 2C19 polymorphism testing. Results Hybrid therapy achieved eradication rates of 77.0% (95% confidence interval ( CI), 70.9-83.7%) in intention-to-treat (ITT), 83.9% (78.9-88.9%) in modified ITT and 86.0% (80.2-91.3%) in per-protocol analyses in a setting with high antibiotic resistance rates (amoxicillin 2.0%, clarithromycin 44.9%, metronidazole 67.3% and dual clarithromycin and metronidazole 33.3%). Adverse reactions occurred in 31.9% patients and 2.7% discontinued medications due to adverse reactions. Good compliance was achieved by 92.0%. Multivariate analyses identified clarithromycin resistance (odds ratio, 3.494; 95% CI, 1.237-9.869), metronidazole resistance (3.012; 1.013-12.054) and poor compliance (5.840; 1.126-30.296) as independent predictors of treatment failure. The eradication rate with dual clarithromycin and metronidazole resistance (70.2%) was markedly decreased compared to isolated clarithromycin resistance (87.5%), isolated metronidazole resistance (88.6%), or dual susceptibility (96.4%) ( p = .014). Conclusions Despite good compliance and safety, hybrid therapy as first-line regimen in populations with high antibiotic resistance rates had unsatisfactory efficacy, primarily due to dual clarithromycin and metronidazole resistance. [ABSTRACT FROM AUTHOR]