Work

Novel DNA gyrase mutations in levofloxacin-resistant Helicobacter pylori isolates from southern Vietnam

Year: 2025

Type: article

Abstract: BACKGROUND: The escalating antibiotic resistance in Helicobacter pylori (H. pylori) has become a significant concern in the management of infections. This study aimed to investigate the mutations associated with levofloxacin resistance in H. pylori isolated from southern Vietnam. METHODS: Levofloxacin-resistant H. pylori strains were isolated from peptic ulcer patients and DNA sequencing of DNA gyrase (gyrA and gyrB) genes was performed. RESULTS: We found that 97 % of resistant isolates bearing at least one mutation in GyrA and 32.3 % had a simultaneous mutation in GyrB. Additionally, we identified three previously known mutations, G85C (1.5 %), N87 (34.3 %), and D91 (14.9 %), within the quinolone-resistance-determining region (QRDR) region of GyrA, which confer resistance through natural transformation and were the most prevalent in our study. Notably, we demonstrated a mutation (A88V MIC 4 μg/mL) in GyrA and four novel mutations (E422R MIC 16 μg/mL, A426G MIC 32 μg/mL, S429E MIC 4 μg/mL, and P443A MIC 4 μg/mL) in GyrB, belonging to the QRDR. Additionally, several mutations outside the QRDR were observed, including R190K (16.4 %), P219A/G (13.4 %), L45F (9 %), P220E (6 %), Y28I (4.5 %), A27L (3 %) in GyrA, and S457A (7.5 %), A382F (5.9 %), L389F (4.5 %), D412R (1.5 %), L460P (1.5 %), I482V (1.5 %), and L518E (1.5 %) that have not been documented in any previous studies and were not functionally validated. CONCLUSION: These results highlight the high genetic diversity and prevalence of levofloxacin-resistant H. pylori strains in southern Vietnam and provide valuable insights into levofloxacin resistance mechanisms for future diagnostic and treatment advancements.

Source: Journal of Microbiology Immunology and Infection

DOI: 10.1016/j.jmii.2025.03.012

Authors: Thi Nhu Le Tran, Ngoc-Niem Bui, Vu Trung Nguyen, Ngoc Anh Tran