Prevalence and rapid identification of clarithromycin-resistant Helicobacter pylori isolates in children

Pediatr Infect Dis J. 2001 Jul;20(7):662-6. doi: 10.1097/00006454-200107000-00005.

Abstract

Background: Little is known about the prevalence of antibiotic-resistant Helicobacter pylori infection in children. Culture and antimicrobial susceptibility testing are generally time-consuming and not a routine in many hospitals.

Objective: To investigate the prevalence of clarithromycin-resistant H. pylori strains in children, to identify those isolates via rapid methodology and to examine the severity of gastritis caused by the antibiotic-resistant H. pylori isolates.

Methods: Enrolled were 245 children investigated for H. pylori infection by endoscopic examination. The gastric antral specimens were subjected to DNA extraction and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) with primers specific to the H. pylori 23S rRNA gene. Conventional bacterial cultures were performed simultaneously as the diagnostic standard. Minimal inhibitory concentrations of clarithromycin and metronidazole were determined by E test. This was used as a standard to determine the sensitivity and specificity of the above PCR-RFLP assay. The specimens were processed for histologic examination and evaluated by the updated Sydney system.

Results: H. pylori was isolated in 67 of the 245 children; 12 (18%) of them were clarithromycin-resistant and 6 (9%) were metronidazole-resistant. No difference in histologic examinations was noted between the antibiotic-resistant and -susceptible strains. We performed PCR-RFLP with all 12 clarithromycin-resistant isolates: 10 had a 23S ribosomal RNA A2144G point mutation; 1 had a mixture of an A2143G point mutant and susceptible strains; and 1 had neither of the 2 mutations.

Conclusions: The prevalence of clarithromycin-resistant H. pylori isolates in Taiwanese children is 18%. PCR-RFLP had a high sensitivity (92%) and specificity (100%) for the clarithromycin resistance gene mutation determination. The dominant mutation is A2144G. PCR-RFLP provides a rapid and accurate approach to detect clarithromycin-resistant strains within 24 h.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Anti-Bacterial Agents / therapeutic use*
  • Child
  • Clarithromycin / therapeutic use*
  • DNA, Bacterial / analysis
  • Drug Resistance, Microbial / genetics
  • Female
  • Gastritis / drug therapy
  • Gastritis / microbiology
  • Gastritis / pathology*
  • Helicobacter Infections / drug therapy*
  • Helicobacter Infections / microbiology
  • Helicobacter Infections / pathology
  • Helicobacter pylori / drug effects*
  • Helicobacter pylori / genetics*
  • Helicobacter pylori / isolation & purification
  • Humans
  • Male
  • Polymerase Chain Reaction
  • Polymorphism, Restriction Fragment Length
  • Severity of Illness Index

Substances

  • Anti-Bacterial Agents
  • DNA, Bacterial
  • Clarithromycin