Korean J Helicobacter Up Gastrointest Res.  2014 Jun;14(2):95-102. 10.7704/kjhugr.2014.14.2.95.

Analysis of Gene Mutations Associated with Antibiotic Resistance in Helicobacter pylori Strains Isolated from Korean Patients

• An B
• Moon BS
• Lim HC
• Lee YC
• Kim H
• Lee G
• Kim SH
• Park M
• Kim JB

• KMID: 2249457
• DOI: http://doi.org/10.7704/kjhugr.2014.14.2.95

Abstract

BACKGROUND/AIMS
This study aims to identify the gene mutation pattern associated with antibiotic resistance for mainly used antibiotics in Helicobacter pylori strains isolated from Koreans.
MATERIALS AND METHODS
Seventy-one H. pylori strains were isolated from gastric mucosal biopsy specimens. The specimens were cultivated and the resistance to 5 antibiotics were assessed by using agar gel dilution method. DNA sequencing was carried out to detect the resistance-related gene mutations.
RESULTS
A point mutation at A2143G of 23S rRNA was observed in all of the clarithromycin resistant strains, but tetracycline resistant strains were not found. Substitution N562Y in penicillin binding protein 1 were observed in an amoxicillin resistant strain (minimum inhibitory concentration [MIC] 2.0microg/mL). Eleven (57.8%) out of 19 levofloxacin resistant strains showed amino acid substitution at N87K (8 strains), N87I, A88V and D91N in GyrA. The truncation in rdxA was detected in 8 (25.0%) out of 32 metronidazole resistant strains. Two out of the 7 patients who failed in first-line treatment of clarithromycin and amoxicillin showed A2143G mutation.
CONCLUSIONS
23S rRNA mutation is closely related to the failure of eradication, however, the fact that five people who have no gene mutation failed eradication implies that other factors are related. As MIC levels in clarithromycin and levofloxacin resistance strains are getting higher, their appropriate gene mutation is more correlated.

Keyword

Helicobacter pylori; Antibiotic resistance; 23S rRNA; Penicillin binding protein 1; GyrA

MeSH Terms

Agar
Amino Acid Substitution
Amoxicillin
Anti-Bacterial Agents
Biopsy
Clarithromycin
Drug Resistance, Microbial*
Helicobacter pylori*
Humans
Levofloxacin
Metronidazole
Penicillin-Binding Proteins
Point Mutation
Sequence Analysis, DNA
Tetracycline
Agar
Amoxicillin
Anti-Bacterial Agents
Clarithromycin
Metronidazole
Penicillin-Binding Proteins
Tetracycline