[Comparison of quantifying Helicobacter pylori gastric infection by culture, histology and C13 urea breath test]

Abstract

Objectives: In Helicobacter pylori infection, the bacterial burden may play a role in the pathogenesis of gastric or duodenal ulcerated lesions. It could also influence the results of antimicrobial therapy. No simple test has been validated to quantify Helicobacter pylori density. The aim of this study was to determine the value of histology and/or 13C-urea breath test to quantify the infection as compared with quantitative culture, taken as a reference method.

Patients and methods: Biopsies samples were taken from the antrum at endoscopy in 72 patients. Thirty-seven patients with positive urease test at 20 minutes were enrolled in the study. Bacterial density was evaluated from biopsies by quantitative culture and semi-quantitative histological examination (score from 0 to 3). The bacterial density was evaluated as well by 13C-urea breath test from the proportion of 13CO2 in exhaled air (delta 13CO2) at 20, 40, and 60 minutes as compared with the basal level.

Results: The bacterial density, evaluated by quantitative culture ranged from 5 CFU to 110,000 CFU per mg of tissue. By histology, a score 1 was found in 5 patients, a score 2 in 17, and a score 3 in 15. delta of 13CO2 measured by 13C-urea breath test ranged from 0.2 to 117.5, from 0.2 to 102, and from 0.6 to 66.7 at 20, 40 and 60 minutes respectively. The quantity of bacteria measured by culture was not significantly higher for these with a score of 3 as compared with those with a pooled score of 1 and 2 (P < 0.05). No significant correlation was found between the results of quantitative culture and these of breath test.

Conclusion: In practice, evaluation of bacterial burden by a histological score seems only accurate for the most severe density (score 3). The 13C-urea breath test does not allow a reliable quantitative evaluation.