Favorable outcomes of culture-based Helicobacter pylori eradication therapy in a region with high antimicrobial resistance.

BACKGROUND: The eradication rate of Helicobacter pylori has declined, mainly due to antimicrobial resistance. To overcome resistance-associated treatment failure, the efficacy of culture-based, susceptibility-guided therapy was demonstrated as the first-line eradication therapy for H pylori infection. AIMS: To evaluate the efficacy of culture-based therapy as the first-line eradication therapy in regions with high levels of antimicrobial resistance. METHODS: Helicobacter pylori-positive patients without previous eradication treatment history were recommended to undergo culture to determine the minimal inhibitory concentration (MIC). If they consented, 7-day clarithromycin-containing PPI triple; 7-day esomeprazole, moxifloxacin, and amoxicillin (MEA) therapy; or 7- or 14-day esomeprazole, bismuth, metronidazole, and tetracycline (quadruple) therapy were administered based on the agar dilution-determined MIC. Eradication, treatment compliance, and adverse events were examined. RESULTS: In total, 74 patients were enrolled, and 69 patients completed the protocols. The overall resistance rates to amoxicillin, clarithromycin, metronidazole, and moxifloxacin were 6.7%, 31.0%, 41.8%, and 39.2%, respectively. The patients were allocated to the PPI triple (n = 50), MEA (n = 8) or quadruple (n = 16) therapy. The eradication rate in the intention-to-treat analysis was 93.1% (69 of 74 patients). The eradication rates in the per-protocol analysis were 100.0% (69 of 69 patients). Epigastric pain, nausea, and vomiting were less common than those of other empirical therapies. CONCLUSIONS: Culture-based, susceptibility-guided therapy is effective first-line eradication therapy, especially in regions with high levels of antimicrobial resistance.

Ultimate eradication rate of Helicobacter pylori after first, second, or third-line therapy in Korea.

BACKGROUND AND AIMS: Resistance rates of Helicobacter pylori to clarithromycin, metronidazole, and quinolone are over 30% in South Korea. The aim of this prospective study was to evaluate the ultimate eradication rate of H. pylori after first, second, or third-line therapy in Korea. METHODS: A cohort of 2202 patients with H. pylori was treated with proton pump inhibitor (PPI)-based triple therapy for seven days. In case of treatment failure or recurrence, moxifloxacin-based triple therapy (MA) or bismuth-based quadruple therapy (QUAD) was randomly given. When the second-line treatment failed or H. pylori recurred, the unused MA or QUAD was used as a third-line treatment. RESULTS: Eighty-six patients had recurrence at least once during consecutive lines of treatments. Among 2116 patients (intention-to-treat [ITT]) without recurrence, 1644 (77.7%, per-protocol [PP]) completely followed our treatment flow. The ITT and PP rates of first-line treatment were 69.8% and 89.3%. After second line, they reached 78.4% (ITT) and 98.4% (PP). The "final" eradication rate up to third line treatment were 80.0% (1692/2116) and 99.8% (1641/1644), respectively. Resistance to clarithromycin showed significantly lower eradication rate (OR 0.358, P < 0.001) than those with susceptible strains in multivariate analysis. However in PP analysis, there was no significant difference in ultimate success rate regarding resistance pattern. CONCLUSION: Final success rate of PP was high, 99.8% in Korea in spite of high antibiotic resistance rates. However, high rate of refusal of further treatment and follow-up loss made ITT eradication rate low. Proper strategy to improve the treatment adherence is needed.

Mutations of Helicobacter pylori associated with fluoroquinolone resistance in Korea.

BACKGROUND AND AIM: Fluoroquinolone resistance of Helicobacter pylori is known to be dependent on mutations in the QRDR of gyrA. This study was performed to investigate the distribution of gyrA point mutations and to evaluate the impact of the mutations on second-line H. pylori eradication therapy. METHODS: After H. pylori isolation from gastric mucosal specimens, fluoroquinolone resistance was examined using the agar dilution method. DNA sequencing of the QRDR of gyrA was performed in 89 fluoroquinolone-resistant and 27 fluoroquinolone-susceptible isolates. Transformation experiments were performed to confirm mutations in the resistant strains. The eradication rates of moxifloxacin-containing triple therapy were evaluated depending on the resistance of fluoroquinolone. RESULTS: The gyrA mutations were detected in 75.3% (55 of 73 strains) of the primary resistant strains and 100% (16 strains) of the secondary resistant strains. The most common mutations were Asp-91 (36.0%) and Asn-87 (33.7%). The MIC values in the transformed strains differed depending on the gyrA mutations, N87, and D91. Six patients with fluoroquinolone-resistant strains received moxifloxacin-containing triple therapy as the second-line therapy, and two of three patients with Asn-87 mutations (66.7%) failed in the eradication. By contrast, three patients with Asp-91 mutations had successful eradication treatment. CONCLUSIONS: Fluoroquinolone resistance of H. pylori was caused by gyrA Asn-87 and Asp-91 point mutations. The Asn-87 mutation seems to be an important determinant of failure of fluoroquinolone-containing triple eradication therapy based on eradication results.