Sequencing-based detection of 23S rRNA domain V mutations in treatment-naïve Helicobacter pylori patients from Malaysia

• Published in: Journal of global antimicrobial resistance. Vol. 23; pp. 345 - 348
• Main Authors: Ng, Heng Kang, Goh, Khean Lee, Chuah, Kee Huat, Thalha, Abdul Malik, Kee, Boon Pin, Por, Lip Yee, Chua, Kek Heng, Puah, Suat Moi
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01-12-2020; Elsevier
• Subjects: 23S rRNA; Biopsy; Clarithromycin resistance; Helicobacter pylori; Malaysia; Treatment-naïve patients; Malaysia; 23S rRNA; Helicobacter pylori; Biopsy; Treatment-naïve patients; Clarithromycin resistance
• ISSN: 2213-7165; 2213-7173
• DOI: 10.1016/j.jgar.2020.10.012

•Total of 37 point mutations were detected, including 6 known and 31 novel mutations.•Results support A2147G as a clinically significant point mutation.•Novel T2929C mutation was associated with an increased treatment failure rate.
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.
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.
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.
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.