Molecular mechanisms of clarithromycin resistance in Helicobacter pylori
Journal
Journal of the Formosan Medical Association
Journal Volume
97
Journal Issue
7
Pages
445-452
Date Issued
1998
Author(s)
Abstract
Combination antibiotic therapy for Helicobacter pylori has now become the standard means of treating peptic ulcer diseases. Clarithromycin is a newly adopted antibiotic for H. pylori eradication. However, resistance to clarithromycin reduces the efficacy of clarithromycin-containing regimens. We explored mechanisms of clarithromycin resistance by evaluating H. pylori for macrolide resistance mechanisms reported in H. pylori and other bacteria. Degenerate polymerase chain reaction analysis of the H. pylori genome failed to yield products homologous to methylase, a drug inactivation enzyme, or efflux pumps. Clarithromycin selection in Escherichia coli NM522, transformed with an expression library that was constructed with genomic DNA from a clarithromycin-resistant strain of H. pylori, revealed six clones that conferred clarithromycin resistance consistently after retransformation. Southern hybridization and DNA sequencing revealed that four of the six clones contained the same locus. Comparison of DNA and amino acid sequences showed that the 1.3-kb DNA fragment had significant homology to the 3- oxoadipate CoA-transferase subunit A (yxjD) and subunit B (yxjE) of Bacillus subtilis. However, the clarithromycin inactivation assay and knockout mutation analysis showed that the gene increased clarithromycin resistance in E. coli, but not in H. pylori. In contrast, sequencing of the 23S rRNA gene in six clarithromycin-resistant H. pylori clinical isolates revealed an A to G transitional mutation at position 2515 of the 23S rRNA gene in all isolates. Natural transformation with the 23S rRNA gene from resistant strains conferred clarithromycin resistance in clarithromycin-sensitive strains. We conclude that the 23S rRNA mutation is sufficient to confer clarithromycin resistance and that it is the major mechanism of clarithromycin resistance in H. pylori.
SDGs
Other Subjects
bacterial dna; bacterial enzyme; clarithromycin; rna 23s; antibiotic resistance; article; bacillus subtilis; bacterial gene; bacterial metabolism; helicobacter pylori; minimum inhibitory concentration; nonhuman; nucleic acid base substitution; nucleotide sequence; polymerase chain reaction; rna gene; strain difference; Amino Acid Sequence; Anti-Bacterial Agents; Base Sequence; Clarithromycin; Coenzyme A-Transferases; Drug Resistance, Microbial; Helicobacter pylori; Humans; Molecular Sequence Data; RNA, Ribosomal, 23S
Type
journal article