Levofloxacin-Resistant <i>Helicobacter pylori </i>in Hong Kong

Abstract

Background: Fluoroquinolone-resistant Helicobacter pylori emerged in 1995 and the resistance was due to point mutation in the gyrA gene. In this study we investigate the resistance mechanism and the antimicrobial susceptibilities of clarithromycin, metronidazole, amoxicillin, tetracycline and telithromycin against levofloxacin-resistant H. pylori in Hong Kong. Methods: One hundred and ninety-one nonduplicate H. pylori isolates were collected during 2004 and 2005, and 25 isolates with levofloxacin zone sizes less than 30 mm were selected for minimal inhibitory concentration determination by agar dilution, gyrA gene amplication and sequencing the amplified gyrA gene. Results: The prevalence of levofloxacin-resistant H. pylori was 11.5% (22/191). Among these levofloxacin-resistant strains, 7 (31.8%) and 10 (45.5%) were resistant to clarithromycin and metronidazole, respectively, 17 (77.3%) had point mutations in gyrA gene at amino acids 87, 91 and 130 and the most frequent mutation point was at position 91. Conclusions: Amoxicillin, tetracycline and telithromycin were active against levofloxacin-resistantH. pylori and levofloxacin resistance was mainly due to point mutation in the gyrA gene, especially at amino acid position 91.

Antimicrobial Sensitivity Pattern of Helicobacter pylori Isolates among Subgroup of Bangladeshi Patients

“…Study conducted in Taiwan 21 , Hong kong 28 , Japan 29 and Italy 30 shown that Levofloxacin resistant rate 9.4%, 11.5%, 15% and 14.6% respectively. In this study Levofloxacin resistance was found among 19.5% of H. pylori isolates and is almost consistent with previous study.…”

Helicobacter pylori: Antibiotic resistance and treatment options

“…Encouragingly, primary levofloxacin resistance appears fairly low in many places where surveys have been done. 1,13 However, as with clarithromycin, secondary resistance emerges readily after failed first-line therapy. Outcome data from audits of salvage eradication therapy have been generally favorable.…”

“…11 On average, Asians have a smaller parietal cell mass than Europeans, which makes them more responsive to PPI. 13 Moreover, there are published data that indicate there is an increased prevalence of the 'poor metabolizer' genotype for PPI in Asians which again would exaggerate the responsiveness to PPI. 13,14 Most PPI are metabolized predominantly through the cytochrome P450 (CYP) enzymes, more specifically through CYP2C19.…”

“…13 Moreover, there are published data that indicate there is an increased prevalence of the 'poor metabolizer' genotype for PPI in Asians which again would exaggerate the responsiveness to PPI. 13,14 Most PPI are metabolized predominantly through the cytochrome P450 (CYP) enzymes, more specifically through CYP2C19. The majority of omeprazole metabolism occurs through his pathway, while esomeprazole > pantoprazole > lansoprazole are less metabolized through this pathway.…”

Effects of Grepafloxacin on the Function of Human Polymorphonuclear Leukocytes and the Phosphorylation of p38 Mitogen-Activated Protein Kinase

“…Many studies on the efflux systems of bacterial cells have been performed so far, e.g. the NQ resistance mechanism [36] as well as the point mutations in gyrA , which encodes DNA gyrase, affecting Mycobacterium tuberculosis [37] , Klebsiella oxytoca [38] or Helicobacter pylori resistance [39] .…”