Substitutions in Penicillin-Binding Protein 1 in Amoxicillin-Resistant Helicobacter pylori Strains Isolated from Korean Patients.
- Author:
Beom Jin KIM
1
;
Jae G KIM
Author Information
1. Department of Internal Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea. jgkimd@cau.ac.kr
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
Helicobacter pylori;
Amoxicillin resistance;
Penicillin-binding proteins;
Amino acid substitution
- MeSH:
Adult;
Amino Acid Sequence;
*Amino Acid Substitution;
Amoxicillin/*pharmacology;
Anti-Bacterial Agents/*pharmacology;
Female;
Helicobacter Infections/drug therapy;
Helicobacter pylori/*chemistry/*drug effects/genetics;
Humans;
Male;
Microbial Sensitivity Tests;
Middle Aged;
*Penicillin Resistance/genetics;
Penicillin-Binding Proteins/*chemistry/genetics;
Republic of Korea;
Sequence Analysis, Protein;
Transformation, Genetic
- From:Gut and Liver
2013;7(6):655-660
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND/AIMS: A worldwide increase in amoxicillin resistance in Helicobacter pylori is having an adverse effect on eradication therapy. In this study, we investigated the mechanism of the amoxicillin resistance of H. pylori in terms of amino acid substitutions in penicillin-binding protein 1 (PBP1). METHODS: In total, 150 H. pylori strains were isolated from 144 patients with chronic gastritis, peptic ulcers, or stomach cancer. The minimum inhibitory concentrations (MICs) of the strains were determined with a serial 2-fold agar dilution method. The resistance breakpoint for amoxicillin was defined as >0.5 microg/mL. RESULTS: Nine of 150 H. pylori strains showed amoxicillin resistance (6%). The MIC values of the resistant strains ranged from 1 to 4 microg/mL. A PBP1 sequence analysis of the resistant strains revealed multiple amino acid substitutions: Val16-->Ile, Val45-->Ile, Ser414-->Arg, Asn562-->Tyr, Thr593-->Ala, Gly595-->Ser, and Ala599-->Thr. The natural transformation of these mutated genes into amoxicillin-sensitive strains was performed in two separate pbp1 gene segments. A moderate increase in the amoxicillin MIC was observed in the segment that contained the penicillin-binding motif of the C-terminal portion, the transpeptidase domain. CONCLUSIONS: pbp1 mutation affects the amoxicillin resistance of H. pylori through the transfer of the penicillin-binding motif.
