Emerging Helicobacter pylori levofloxacin resistance and novel genetic mutation in Nepal. Issue 1 (December 2016)

• Record Type: Journal Article
• Authors: Miftahussurur, Muhammad; Shrestha, Pradeep; Subsomwong, Phawinee; Sharma, Rabi; Yamaoka, Yoshio
• Is Part Of: BMC microbiology. Volume 16:Issue 1(2016)
• Page Start: 1
• Page End: 10
• Publication Date: 2016-12
• Subjects: Nepal -- Drug resistance -- Helicobacter pylori -- Genetic mutation; Microbiology -- Periodicals; 579.05
• DOI: 10.1186/s12866-016-0873-6
• Languages: English
• ISSNs: 1471-2180

Abstract

Abstract Background The prevalence ofHelicobacter pylori antibiotic susceptibility in the Nepalese strains is untracked. We determined the antibiotic susceptibility forH. pylori and analyzed the presence of genetic mutations associated with antibiotic resistance in Nepalese strains. Results This study included 146 consecutive patients who underwent gastroduodenal endoscopy in Kathmandu, Nepal. Among 42 isolatedH. pylori, there was no resistance to amoxicillin and tetracycline. In contrast, similar with typical South Asian patterns; metronidazole resistance rate in Nepalese strains were extremely high (88.1 %, 37/42). Clarithromycin resistance rate in Nepalese strains were modestly high (21.4 %, 9/42). Most of metronidazole resistant strains had highly distributedrdxA andfrxA mutations, but were relative coincidence without a synergistic effect to increase the minimum inhibitory concentration (MIC). Among strains with the high MIC, 63.6 % (7/11) were associated with frameshift mutation at position 18 offrxA with or withoutrdxA involvement. However, based on next generation sequencing data we found that one strain with the highest MIC value had a novel mutation in the form of amino acid substituted at Ala-212, Gln-382, Ile-485 ofdppA and Leu-145, Thr-168, Glu-117, Val-121, Arg-221 indapF aside from missense mutations in full-lengthrdxA. Mutations at Asn-87 and/or Asp-91 of thegyrA were predominantly in levofloxacin-resistant strains. ThegyrB mutation had steady relationship with thegyrA 87–91 mutations. Although three (44.4 %) and two (22.2 %) of clarithromycin resistant strains had point mutation on A2143G and A2146G, we confirmed the involvement ofrpl22 andinfB in high MIC strains without an23SrRNA mutation. Conclusions The rates of resistance to clarithromycin, metronidazole and levofloxacin were high in Nepalese strains, indicating that these antibiotics-based triple therapies are not useful as first-line treatment in Nepal. Bismuth or non-bismuth-based quadruple regimens, furazolidone-based triple therapy or rifabutin-based triple therapy may become alternative strategy in Nepal.