Heng Kang Ng1, Khean Lee Goh2, Kee Huat Chuah2, Abdul Malik Thalha2, Boon Pin Kee1, Lip Yee Por3, Kek Heng Chua4, Suat Moi Puah5. 1. Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. 2. Department of Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. 3. Department of Computer System and Technology, Faculty of Computer Science & Information Technology, University of Malaya, 50603 Kuala Lumpur, Malaysia. 4. Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. Electronic address: khchua@um.edu.my. 5. Department of Biomedical Science, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia. Electronic address: suatmoi@um.edu.my.
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.
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. pyloriinfection 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.
Authors: A Karvelas; B Martinez-Gonzalez; V P Papadopoulos; M Panopoulou; D Sgouras; K Mimidis Journal: Hippokratia Date: 2021 Apr-Jun Impact factor: 0.522