Clinical Usefulness of Antimicrobial Susceptibility Test for Helicobacter pylori

Abstract

Background : Antimicrobial resistance of Helicobacter pylori is considered as the main cause of failure of eradication therapy. Because resistance to metronidazole has been reported in 25.8% to 66.2% of H. pylori, a combination of proton pump inhibitors (PPI), amoxicillin, and clarithromycin is currently recommended as a primary therapy. We investigated the prevalence of antimicrobial resistance to the primary drugs and the impact of antimicrobial resistance on eradication rates.Methods : Between May and August 2005, H. pylori isolates from 93 patients were tested for antimicrobial susceptibility at Asan Medical Center. Susceptibility tests of clarithromycin and amoxicillin were performed by the disk diffusion method and those of metronidazole and tetracycline by Etest (AB Biodisk, Solna, Sweden). The medical records of the patients were reviewed to collect the data such as demographic findings, previous and current eradication therapies, and bacteriological outcome. The appropriate therapy was defined as three-drug-combination including susceptible drugs only, or four-drug-combination including metronidazole in the case of metronidazole-resistance.Results : Resistance rates to clarithromycin and metronidazole were 17.2% and 33.3%, respectively, but there was no resistance to tetracycline and amoxicillin. The eradication was successful in 32 of the 36 patients (88.9%) who received the appropriate therapy, but none of 4 patients who received an inappropriate therapy (P<0.01).Conclusions : Resistance to clarithromycin seemed to increase and contribute to the failure of eradication therapy. For the appropriate therapy of H. pylori infection, the susceptibility results should be reported before initiation of the eradication therapy. (Korean J Lab Med 2006;26:179-84)

Resistance of Helicobacter pylori strains to antibiotics in Korea with a focus on fluoroquinolone resistance

“…The gyr A mutation patterns were different from those of the previous Korean study, which showed that all the resistance mutation patterns were associated with Asn91. 35 Interestingly, metronidazole resistance was significantly decreased in our study. 16 Other mutations were Asn91 (10/29, 34.5%), Ala88 (2/29, 6.9%) and Arg130Lys.…”

Clarithromycin and Amoxicillin Susceptibility Testing ofHelicobacter pyloriby Disk Diffusion Method

“…CLR에 대한 H. pylori 내성률로 볼 때 우리나라에 서 H. pylori 치료 시 항균제 재치료 시 뿐만 아니라 초회 치료 시에도 CLR에 대한 감수성 검사가 필요함을 시사한다 [4,7].…”

Second-line Helicobacter pylori Eradication: A Randomized Comparison of 1-week or 2-week Bismuth-containing Quadruple Therapy

“…In the previous study, the treatment‐naïve metronidazole resistance rate for metronidazole was decreased from 32.9% in 2003–2006 to 28.0% in 2007–2009 [16]. In Asan Medical Center, it was decreased from 45.1% (28/62) in 2005 to 33.3% (42/154) in 2007 [20]. Another plausible explanation is the geographic difference between the previous study and our study, which showed different antibiotic resistance patterns according to the institution [21].…”