Analysis of the in vitro quinolones resistance in Helicobacter pylori strains isolated in Zhejiang province

Abstract

Objective To investigate the in vitro quinolones resistance in Helicobacter pylori (HP) strains isolated in Zhejiang province and to provide references for the clinical application of quinolones in the eradication of HP infection. Methods A total of 713 HP strains were isolated from several hospitals located in different regions of Zhejiang province from April to June 2013. Drug sensitivity test was performed to measure the resistance of those HP strains to levofloxacin and moxifloxacin by using the agar dilution method recommended by the Clinical and Laboratory Standards Institute (CLSI). The antibiotic solutions were added to the agar and diluted into corresponding critical concentrations. The mixed liquors were placed in dilution plates and added with the bacteria suspension. If there were bacterial expansion on the plates after incubation, the strains were considered to be drug-resistant strains. Results The resistance rates of 713 HP strains to levofloxacin and moxifloxacin were 19.50%. In addition to the Jinhua area, drug resistance rates in the other 7 areas including Hangzhou, Wenzhou, Shaoxing, Jiaxing, Taizhou, Lishui and Zhoushan were above 15%. The highest drug resistance rate of HP was found in Wenzhou, which was significantly higher than that in Jinhua area (26.40% vs 9.52%, P<0.05). No significant differences in the resistance rate of HP to quinolone were found between Wenzhou area and the other regions in Zhejiang. Conclusion Compared with amoxicillin and furazolidone, higher resistance rates of HP to levofloxacin and moxifloxacin were observed in Zhejiang province. Because the mechanisms of drug resistance to levofloxacin and moxifloxacin were same and the drug targets within HP to which the two antibiotics binding were similar, levofloxacin and moxifloxacin shared common characteristics of drug resistance among HP strains, indicating that prescription of the two antibiotics in replacement should be avoided in clinical treatment of HP drug-resistant strains. Key words: Helicobacter pylori; Quinolones; Drug sensitivity test; Resistance