The relationship between consumption of antimicrobial agents and the prevalence of primary Helicobacter pylori resistance

Background. Primary and acquired resistance to the antimicrobial agents is a primary reason for the failure of Helicobacter pylori eradication therapies. We assessed the primary antibiotic resistance rates of H. pylori to three different antibiotics and its relationship due to the annual antibiotic consumption in Japan during the period prior to approval of anti‐H. pylori therapy in Japan. Materials and Methods. Antibiotic susceptibility was tested using the agar dilution method for clarithromycin, amoxicillin and metronidazole. Isolates were considered resistant when the MIC value was > 8 mg/l for metronidazole, > 1 mg/l for clarithromycin and < 0.5 mg/l for amoxicillin. Results. Helicobacter pylori isolates were obtained from 593 Japanese patients from 1995 to 2000. Primary resistance of H. pylori to clarithromycin, metronidazole and amoxicillin was found in 11%, 9% and 0.3% strains, respectively. The proportion with clarithromycin resistance significantly increased from 7% in 1997–98 to 15.2% in 1999–2000 (p = .003). During the same period the metronidazole resistance rate also increased from 6.6% in 1997–98 to 12% in 1999–2000 (p = .02). The prevalence of clarithromycin and metronidazole was related to the annual consumption of these antimicrobial agents. Conclusion. Resistance rates for both clarithromycin and metronidazole appear to reflect the annual consumption of these agents. The high rate of clarithromycin resistance in Japan suggests that the effectiveness of clarithromycin‐based therapies may be compromised in the near future.     

Dual-Priming Oligonucleotide-Based Multiplex PCR for the Detection of Helicobacter pylori and Determination of Clarithromycin Resistance with Gastric Biopsy Specimens

Background:  Assessment of Helicobacter pylori ( H. pylori ) clarithromycin resistance has rarely been performed routinely despite an increasing resistance rate. Our aim was to develop and evaluate the use of dual-priming oligonucleotide (DPO)-based multiplex polymerase chain reaction (PCR) to detect point mutations in the 23S rRNA gene responsible for clarithromycin resistance of H. pylori.
Materials and Methods:  Gastric biopsy specimens from 212 untreated patients with dyspepsia were examined by culture, histology, and DPO-based multiplex PCR. A disk diffusion test and E-test were used for performing phenotypic antibiotic susceptibility tests.
Results:  Among the biopsy specimens tested, 22.2% (47/212), 42.5% (90/212), and 41.5% (88/212) of the specimens were classified as H. pylori positive by culture, histology, and DPO-based multiplex PCR, respectively. Among 96 strains identified by either culture or DPO-based multiplex PCR, 80 strains were clarithromycin-susceptible and 16 strains (16.7%) were clarithromycin-resistant. There was 94.1% (32/34) concordance between phenotypic susceptibility tests and DPO-based multiplex PCR. In two patients with discrepant results, only DPO-based multiplex PCR detected clarithromycin-resistant strains. DPO-based multiplex PCR identified additional 49 clarithromycin-resistant or clarithromycin-susceptible H. pylori among 165 culture-negative specimens.
Conclusions:  DPO-based multiplex PCR can be used as a practical method for the detection of H. pylori infection and the determination of clarithromycin susceptibility in addition to phenotypic antimicrobial susceptibility tests.     

A Randomized Clinical Trial to Determine the Efficacy of Regimens Containing Clarithromycin, Metronidazole, and Amoxicillin Among Histologic Subgroups for Helicobacter pylori Eradication in a Developing Country

Background: Most treatments deemed effective for Helicobacter pylori eradication in developed countries are less effective in developing countries. Regimens containing clarithromycin, metronidazole, and amoxicillin seem efficacious despite antibiotic resistance, and may be a viable option in developing countries. Materials and Methods: We evaluated the efficacy of a 14‐day regimen with 500 mg clarithromycin b.i.d., 500 mg metronidazole t.i.d., and 500 mg amoxicillin t.i.d. (with and without a proton pump inhibitor), and a 10‐day regimen containing 500 mg clarithromycin b.i.d., 1 g amoxicillin b.i.d., and 20 mg omeprazole b.i.d. in Pasto, Colombia, using a randomized, single‐blind design stratified by presence of atrophic gastritis. Results: H. pylori was eradicated in 86.8% and 85.3% of the participants randomized to a clarithromycin‐metronidazole‐amoxicillin and clarithromycin‐amoxicillin‐omeprazole regimens, respectively (p = .79). Per‐protocol analyses indicated greater efficacy for the clarithromycin‐metronidazole‐amoxicillin regimen (97%) versus the clarithromycin‐amoxicillin‐omeprazole regimen (86%) (p = .04), particularly for participants with atrophic gastritis (clarithromycin‐metronidazole‐amoxicillin = 100%, clarithromycin‐amoxicillin‐omeprazole = 81%; p = .02). Adverse events were mild, but adverse event‐related non‐compliance was reported more often for regimens containing clarithromycin, metronidazole, and amoxicillin. Conclusions: Our results suggest that an eradication rate of > 85% can be achieved with 14‐day clarithromycin, metronidazole, and amoxicillin and 10‐day clarithromycin, amoxicillin, and omeprazole regimens in Pasto, Colombia. The regimens containing clarithromycin, metronidazole, and amoxicillin appear to be superior to the clarithromycin, amoxicillin, and omeprazole regimen for compliant participants and those with atrophic gastritis. Our findings provide treatment options for a population in a developing country with a high prevalence of H. pylori infections and antibiotic resistance.     

Levofloxacin-containing triple therapy to eradicate the persistent H. pylori after a failed conventional triple therapy

OBJECTIVE: To identify the optimal dosage of levofloxacin to eradicate persistent Helicobacter pylori when triple therapy with amoxicillin, clarithromycin, and omeprazole fails. METHODS: We investigated 124 patients whose triple therapy including clarithromycin had failed. Clarithromycin resistance was indirectly assessed by the (13)C-urea breath test, with a post-treatment value cut-off point at 15. All patients were randomly divided into two groups, to receive 1-week amoxicillin 1 g and lansoprazole 30 mg twice daily, plus either levofloxacin 500 mg once (ALL-500 group) or twice daily (ALL-1000 group). Six weeks later, the (13)C-urea breath test was repeated to assess whether H. pylori was eradicated. RESULTS: Intention-to-treat (ITT) and per-protocol (PP) analysis showed no difference in H. pylori eradication rates in both the ALL-500 and ALL-1000 groups (ITT: 79% vs. 80.6%, p > .05; PP: 86% vs. 87.5%, p > .05). For both groups, the per-protocol H. pylori eradication rates were also similarly high between patients with a post-treatment value of (13)C-urea breath test < or = 15 and those with a value > 15 (ALL-500: 85% vs. 86.5%, p > .05; ALL-1000: 88.9% vs. 86.8%, p > .05). CONCLUSION: One-week levofloxacin 500 mg daily-based triple therapy is effective for eradicating the persistent H. pylori after a failed triple therapy with amoxicillin, clarithromycin, and omeprazole.     

Is There a Benefit to Extending the Duration of Helicobacter pylori Sequential Therapy to 14 Days?

Background and Aims: Ten‐day sequential therapy with a proton‐pump inhibitor (PPI) and amoxicillin followed by a PPI, clarithromycin, and an imidazole typically achieves Helicobacter pylori (H. pylori) eradication rates between 90 and 94% (i.e., Grade B success). It has been suggested that prolonging the duration of therapy might improve the treatment success. We tested whether prolonging treatment duration to 14‐days would improve the results to 95% or greater eradication. Methods: This was a multi‐center, single site, pilot study in which H. pylori‐infected patients received a 14‐day sequential therapy (esomeprazole and amoxicillin for 7 days followed by esomeprazole, clarithromycin, and metronidazole for 7 days). H. pylori status was assessed 8 weeks after therapy. Success was defined as achieving 95% or greater eradication by per‐protocol (PP) analysis. Results: One hundred and twenty‐three subjects received the 14‐day sequential therapy. The eradication rate was 93.9% (95% confidence interval [CI], 89.5–98.3%) by PP and 91.9% (95% CI, 87.1–96.7%) by intention‐to‐treat analysis. Adverse events were experienced by 21.1%; compliance of 90% or greater was 95.9%. Conclusions: Extending sequential therapy to 14 days did not result in improving the treatment outcome to 95% or greater.     

Evaluation of Two Triple‐Therapy Regimens with Metronidazole or Clarithromycin for the Eradication of H. pylori Infection in Vietnamese Children: a Randomized,Double‐Blind Clinical Trial

Background: Eradication of Helicobacter pylori infection in children in developing countries needs further investigations upon which to base treatment recommendations. The aim of the study was to compare two 2‐week triple therapies in a randomized double‐blind trial. Materials and Methods: In order not to exceed recommended dosages, the 238 H. pylori‐infected children, aged 3 to 15 years (mean 8.6), were divided in two weight categories receiving at weights 13–22 kg: lansoprazole 15 mg once‐daily and amoxicillin 500 mg twice‐daily with metronidazole 250 mg twice‐daily or clarithromycin 250 mg once‐daily; at weights 23–45 kg: lansoprazole 15 mg and amoxicillin 750 mg with metronidazole 500 mg or clarithromycin 250 mg, all administered twice daily. H. pylori status was assessed by culture and a monoclonal‐based antigen‐in‐stool test (Premier Platinum HpSA PLUS) and side effects by structured questionnaires. Results: The overall per‐protocol eradication (n = 233) was similar in the two treatment regimens, 62.1% for the metronidazole and 54.7% for the clarithomycin‐containing therapy. Eradication rate was higher in children ≥ 23 kg (70.9%) than in children < 23 kg (45.7%). In children ≥ 23 kg (n = 117) that received twice‐daily administration of all drugs, efficacy of the methronidazole and clarithromycin‐containing treatments were 69.5% and 72.4%, respectively. Conclusions: The two treatments gave similar eradication rates. Significant differences for both treatments were found by weight, which could be the result of the once‐daily proton pump inhibitor and clarithromycin and/or more antibiotic resistant strains in younger children.     

Mycobacterium massiliense is differentiated from Mycobacterium abscessus and Mycobacterium bolletii by erythromycin ribosome methyltransferase gene (erm) and clarithromycin susceptibility patterns

Erythromycin ribosome methyltransferase gene (erm) sequences of Mycobacterium massiliense and Mycobacterium bolletii isolates were newly investigated. Forty nine strains of M. massiliense that were analyzed in the present study had a deleted erm(41). Due to a frame‐shift mutation, large deletion, and truncated C‐terminal region, the Erm(41) of M. massiliense had only 81 amino acids encoded by 246 nucleotides. Corresponding to these findings, most of the M. massiliense isolates (89.8%) were markedly clarithromycin susceptible, but resistant strains invariably had a point mutation at the adenine (A₂₀₅₈ or A₂₀₅₉) in the peptidyltransferase region of the 23S rRNA gene, which is quite different from Mycobacterium abscessus and M. bolletii. In addition, erm(41) sequences of M. massiliense were more conserved than those of M. abscessus and M. bolletii. The results of species identification using erm(41) showed concordant results with those of multi‐locus sequence analysis (rpoB, hsp65, sodA and 16S‐23S ITS) where there were originally inconsistent results between rpoB and hsp65 sequence analysis in previous research. Therefore, erm(41) PCR that was used in the present study can be efficiently used to simply differentiate M. massiliense from M. abscessus and M. bolletii.     

Identification of a novel mutation affecting domain V of the 23S rRNA gene in Helicobacter pylori

BACKGROUND: This study analyzes clarithromycin resistance status and 23S rRNA gene mutations in Helicobacter pylori strains from Central Italian patients. MATERIALS AND METHODS: H. pylori strains from 235 dyspeptic patients (205 with no history of clarithromycin exposure and 30 referred for failure of eradication therapy) were tested for clarithromycin resistance by screening agar method and E-test. Resistant strains were analyzed for mutations of the 23S rRNA gene by PCR-RFLP and sequencing. RESULTS: Primary resistance was observed in strains from 43/205 (21%) patients with no history of clarithromycin exposure and secondary resistance in 30/30 (100%) strains from previously treated patients. A single mutant strain was detected in 54/73 (74%) cases, a mixture of one or more mutant(s) plus the wild type in the remaining 19/73 (26%) cases. One 23S rRNA gene mutation (A-->T transversion at nucleotide 2144) in the peptidyltransferase region of domain V was novel. CONCLUSIONS: This study shows: (a) a high prevalence of H. pylori strains with primary or secondary clarithromycin resistance in an urban area of Central Italy; (b) colonization by both mutant and wild-type H. pylori in the same patient; (c) a novel variant of the H. pylori 23S rRNA gene.