Sequencing-based detection of 23S rRNA domain V mutations in treatment-naïve Helicobacter pylori patients from Malaysia.
J Glob Antimicrob Resist 2020;
23:345-348. [PMID:
33137535 DOI:
10.1016/j.jgar.2020.10.012]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 09/28/2020] [Accepted: 10/14/2020] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVES
In Malaysia, the prevalence of Helicobacter pylori resistance to clarithromycin is increasing. This study aimed to determine mutations in the 23S rRNA domain V directly using bacterial DNA extracted from gastric biopsy specimens with a urease-positive result.
METHODS
A 1085-bp fragment of 23S rRNA domain V from samples of 62 treatment-naïve patients with H. pylori infection was amplified by PCR with newly designed primers, followed by sequencing.
RESULTS
Of the 62 cases, 42 patients were treated with clarithromycin-based triple therapy and 20 patients were treated with amoxicillin and proton pump inhibitor only; both therapies showed successful eradication rates of 70-73.8%. Sequencing analysis detected 37 point mutations (6 known and 31 novel) with prevalences ranging from 1.6% (1/62) to 72.6% (45/62). A2147G (aka A2143G) appears to be associated with a low eradication rate [40% (2/5) failure rate and 13.3% (6/45) treatment success rate], supporting its role as a clinically significant point mutation. T2186C (aka T2182C) was found in 71.1% (32/45) and 80% (4/5) of treatment success and failure cases, respectively, suggesting that the mutation is clinically insignificant. The eradication success rate in patients with the novel T2929C mutation was decreased three-fold (6.7%; 3/45) compared with the failure rate (20%; 1/5), suggesting that it may play an important role in clarithromycin resistance, thus warranting further study.
CONCLUSION
This study identified multiple known and novel mutations in 23S rRNA domain V through direct sequencing. Molecular detection of clarithromycin resistance directly on biopsies offers an alternative to conventional susceptibility testing.
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