Antibacterial Resistance Patterns of Helicobacter pylori Clinical Isolates From Gastric Biopsy of Patients in Yazd

Antibiotic resistance pattern and frequency of cagA and vacA genes in Helicobacter pylori strains isolated from patients in Tabriz city, Iran

Objective

Helicobacter pylori is one of the most common causes of gastric infections in humans. It is estimated that approximately 50% of people around the world are infected with this bacterium. This study aimed to determine the antibiotic resistance pattern, as well as the frequency of cagA and vacA genes in H. pylori isolates obtained from patients in the clinical centers in Tabriz city, Iran.

Results

The culture method detected 100 (45.25%) H. pylori isolates from 221 biopsy samples during 3 years. The results showed that 63% and 81% of the isolates were positive for cagA and vacA genes, respectively. The highest resistance of isolates was seen against metronidazole (79%) and amoxicillin (36%), respectively. Also, the isolates showed the least resistance to tetracycline (8%).

An Updated Systematic Review and Meta-Analysis on the Helicobacter pylori Antibiotic Resistance in Iran (2010-2020)

This updated systematic review and meta-analysis followed two objectives: (1) to determine Helicobacter pylori antibiotic resistance in Iran during 2010-2020 and (2) to assess the trend of resistance from 1997 to 2020. A systematic search in multiple databases, including ISI Web of Knowledge, PubMed, Scopus, Google Scholar, and the Scientific Information Database (SID), was performed using MeSH-extracted keywords. Meta-analysis was done on extracted data from a total of 27 included citations published between 2010 and January 20, 2020. The overall mean prevalence of H. pylori resistance was 64.9% for metronidazole, 25.3% for clarithromycin, 20.7% for amoxicillin, 16.1% for tetracycline, 21.9% for levofloxacin, 22.8% for rifampicin, 27.2% for furazolidone, 32.3% for ciprofloxacin, and 38.7% for erythromycin. In addition, the prevalence of multidrug-resistant strains of H. pylori was 26.5% in Iran. The pooled prevalence of point mutations A2143G, A2142G, and A2142C associated with clarithromycin resistance were 46.6%, 37.2%, and 5.5%, respectively; mutations in frxA and rdxA genes associated with metronidazole resistance were 46.4% and 19.7%, respectively; gyrA and gyrB genes mutations among fluoroquinolone-resistant strains were 55.3% and 48.2%, respectively; and resistance associated with integrons was 47%. According to the present findings, resistance of H. pylori to antibiotics used for eradication therapy has reached an alarming level in Iran. Furthermore, the trend of H. pylori resistance has increased between 1997 and 2020. Hence, continuous surveillance on resistance patterns, logical prescription and appropriate consumption of antibiotics, and selecting effective therapeutic regimens in accordance with local resistance patterns are required to prevent further spread of resistance and ensuing treatment failures.

Efficacy and Tolerability of Two Quadruple Regimens: Bismuth, Omeprazole, Metronidazole with Amoxicillin or Tetracycline as First-Line Treatment for Eradication of Helicobacter Pylori in Patients with Duodenal Ulcer: A Randomized Clinical Trial

AIM

To evaluate the efficacy and tolerability of tetracycline vs. high-dose amoxicillin in bismuth-based quadruple therapy for Helicobacter pylori(H. pylori) eradication.

METHODS

This randomized, open-label clinical trial included 228 patients with H.pylori infection and duodenal ulcer without a history of H.pylori treatment. Patients were randomly divided into two groups. The amoxicillin group received metronidazole 500mg, bismuth subcitrate 240mg, and amoxicillin 1000mg, all three times a day, plus omeprazole 20 mg twice a day, for 14 days. The tetracycline group received metronidazole 500mg three times a day; bismuth subcitrate240mg and tetracycline HCl 500mg, both four times a day; and omeprazole 20 mg twice a day, for 14 days. Evaluation for compliance and drug-relatedadverse effects were evaluated at the end of two weeks. Eight weeks after the end of treatment, the rate of H.pylori eradication was assessed by the C13urease breath test.

RESULTS

There were no significant demographic differences between the two groups. Eradication rate was higher with the amoxicillin-containing regimen than the tetracycline-containing regimen: 105/110 (95.51%; 95% confidence interval, 91.5%-99.3%) vs. 88/105 (83.8%; 95%CI, 76.7%-90.8%) by per-protocol analysis (p = 0.005) and 92.9% (95%CI, 88.1%-97.6%) vs. 76.5% (95%CI, 68.7%-84.2%) by intention-to-treat analysis (ITT, p = 0.001). Adverse effects were significant higher in the tetracycline groupthan in the amoxicillin group (65.2% vs. 43.4%; p = 0.001).

CONCLUSION

Bismuth-based quadruple therapy including high-dose amoxicillin and metronidazole achieved an acceptable rate of H.pylori infection eradication with good tolerance in patients with duodenal ulcer. This regimen can overcome treatment resistance in areas with high prevalence of metronidazole and clarithromycin resistance.

TRIAL REGISTRATION

The Thai Clinical Trial Registry (TCTR) 20170623004.