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Prevalence and rapid identification of clarithromycin-resistant Helicobacter pylori isolates in children
1Department of Pediatrics, National Taiwan University, College of Medicine and Hospital, Taipei.
Insights
Antibiotic-resistant Helicobacter pylori infection is prevalent in 18% of Taiwanese children. Rapid PCR-RFLP accurately detects clarithromycin resistance, identifying the A2144G mutation.
Area of Science:
- Pediatric Infectious Diseases
- Microbiology
- Gastroenterology
Background:
- Prevalence of antibiotic-resistant Helicobacter pylori in children is largely unknown.
- Standard culture and susceptibility testing for H. pylori are time-consuming and not routinely performed.
Purpose of the Study:
- Determine the prevalence of clarithromycin-resistant H. pylori in children.
- Identify clarithromycin-resistant H. pylori using a rapid method.
- Assess the severity of gastritis linked to antibiotic-resistant H. pylori.
Main Methods:
- Endoscopic gastric antral specimens from 245 children were analyzed.
- Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) targeted the H. pylori 23S rRNA gene.
- Conventional cultures and E tests determined antimicrobial susceptibility, serving as a reference for PCR-RFLP accuracy.
Main Results:
- H. pylori was found in 67 children; 18% were resistant to clarithromycin and 9% to metronidazole.
- PCR-RFLP identified the A2144G mutation in 10 of 12 clarithromycin-resistant isolates.
- No significant differences in gastritis severity were observed between resistant and susceptible strains.
Conclusions:
- 18% of H. pylori isolates in Taiwanese children exhibit clarithromycin resistance, primarily due to the A2144G mutation.
- PCR-RFLP offers a rapid (within 24 hours) and highly accurate method (92% sensitivity, 100% specificity) for detecting clarithromycin resistance gene mutations.
- This rapid detection method is crucial for managing pediatric H. pylori infections.
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.