Fluorescence in situ hybridization vs. epsilometer test for detection of clarithromycin-susceptible and clarithromycin-resistant Helicobacter pylori strains in gastric biopsies from children.
OBJECTIVE
To compare the results of culture and epsilometer test with fluorescence in situ hybridization for the detection of Helicobacter pylori and the presence of clarithromycin-susceptible and clarithromycin-resistant strains in antral biopsies from children.


METHODS
Antral biopsies from 149 unselected children were investigated prospectively; 15 had previously received anti-H. pylori therapy. H. pylori status was defined by histology, rapid urease test and 13C-urea breath test. Fluorescence in situ hybridization was applied on fresh tissue with probes specific for the clarithromycin-susceptible wild type and three clarithromycin-resistant mutants. Susceptibility to clarithromycin was tested by epsilometer test in two laboratories.


RESULTS
Culture and fluorescence in situ hybridization gave negative results in all 66 H. pylori-negative children (specificity, 100%). Of 83 infected children, cultures were successful in 75 (90%), epsilometer test in 71 (86%) and fluorescence in situ hybridization in 77 (93%). Eleven children (13%) showed discrepant results between the applied methods, indicating mixed infection. Clarithromycin-resistant isolates were identified in 16 of 73 previously untreated children.


CONCLUSIONS
Primary resistance to clarithromycin is common (22%) in H. pylori isolates from children living in Germany. Fluorescence in situ hybridization is an excellent, fast method for the detection of H. pylori and clarithromycin-resistant mutants in gastric biopsies. Multiple biopsies identify mixed infections, indicating that clarithromycin-resistant and clarithromycin- susceptible strains are not evenly distributed within the stomach.
Feydt-Schmidt
A
A
Dr v Haunerches Kinderspital, Ludwig-Maximilians University, Munich, Germany.
Rüssmann
H
H
Lehn
N
N
Fischer
A
A
Antoni
I
I
Störk
D
D
Koletzko
S
S
D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001706:Biopsy; D001944:Breath Tests / Q000379:methods; D002648:Child; D002675:Child, Preschool; D017291:Clarithromycin / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D005260:Female; D016481:Helicobacter Infections / Q000175:diagnosis* / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests / Q000379:methods; D011446:Prospective Studies; D011706:Pyloric Antrum / Q000382:microbiology; D012680:Sensitivity and Specificity
D000900:Anti-Bacterial Agents; D017291:Clarithromycin