Detection of clarithromycin-resistant Helicobacter pylori in frozen gastric biopsies from pediatric patients by a commercially available fluorescent in situ hybridization.
Clarithromycin resistance is an important factor of eradication failure. A commercially available fluorescent in situ hybridization (FISH) kit (creaFAST) was used to detect H. pylori infection and the resistance to clarithromycin in frozen biopsies. A total of 33 biopsies, H. pylori culture-positive, obtained from pediatric patients were retrospectively studied. Clarithromycin resistance was compared with MICs detected by E-test from H. pylori clinical isolates. All culture-positive biopsies were positive by FISH. Detection of clarithromycin resistance showed sensitivity of 90%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 86.7% compared with results obtained by E-test. Discrepant results were 2 biopsies, clarithromycin-susceptible by FISH but intermediate by E-test. In conclusion, FISH technology is a rapid, easy-to-implement, and reliable cultivation-independent method for routine application; however, when frozen biopsies are studied, some modification of the recommended procedure should be used to obtain better results.
Vega
Alba E
AE
Area Microbiología, Facultad de Química, Bioquímica y Farmaçia, Universidad Nacional de San Luis, Chacabuco y Pedernera, 5700 San Luis, Argentina.
Alarcón
Teresa
T
Domingo
Diego
D
López-Brea
Manuel
M
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001706:Biopsy; D002648:Child; D002675:Child, Preschool; D017291:Clarithromycin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial / Q000235:genetics; D005615:Freezing; D016481:Helicobacter Infections / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D008826:Microbial Sensitivity Tests / Q000379:methods; D011933:Reagent Kits, Diagnostic; D013270:Stomach
D000900:Anti-Bacterial Agents; D011933:Reagent Kits, Diagnostic; D017291:Clarithromycin