Posttreatment ¹³C-urea breath test is predictive of antimicrobial resistance to H. pylori after failed therapy

OBJECTIVE: We tested whether a ¹³C-urea breath test can predict antimicrobial resistance of Helicobacter pylori (H. pylori). METHODS: Seventy patients who had failed triple eradication therapy and 108 untreated H. pylori-infected patients were given a ¹³C-urea breath test, endoscopy for culture of H. pylori, and assessment of clarithromycin resistance. The patients who had failed triple therapy then received 1 week of quadruple therapy to eradicate residual H. pylori. RESULTS: The posttreatment value of the ¹³C-urea breath test expressed as excessive δ ¹³CO₂ per ml (ECR) was higher in patients with residual H. pylori with clarithromycin resistance than in those without (23.8 vs 10.6; P<.0001). With a cutoff of ECR >or≤ 15, the ¹³C-urea breath test was 88.6% sensitive and 88.9% specific in predicting clarithromycin resistance of residual H. pylori. The H. pylori eradication rate of the rescue regimen was higher for patients with a post-treatment ECR of the ¹³C-urea breath test ≤ 15 than for those with a value > 15 (93.8% vs 73.3%; P<.05). In contrast, in treatment-naive H. pylori-infected patients, the pretreatment value of the ¹³C-urea breath test did not differ between patients infected with clarithromycin-resistant or-sensitive Isolates (P>.05). CONCLUSION: The posttreatment value of the ¹³C-urea breath test is predictive of clarithromycin resistance in residual H. pylori after failed triple therapy and predicts efficacy of the rescue regimen. The value of the noninvasive test is promising for primary care physicians who need to select a rescue regimen without invasive H. pylori culture.