Triple Therapy with High-Dose Proton-Pump Inhibitor, Amoxicillin, and Doxycycline Is Useless for Helicobacter pylori Eradication: A Proof-of-Concept Study

IntroductionHelicobacter pylori resistance to antibiotics is steadily increasing and multidrug-resistant strains are common and difficult to eliminate, mainly in countries where bismuth, tetracycline, furazolidone, and rifabutin are unavailable. AimTo evaluate the efficacy and safety of a triple therapy with proton-pump inhibitor (PPI), amoxicillin, and doxycycline in patients with multidrug-resistant H.pylori. Patients and MethodsThis prospective study involved 16 patients (13 females; mean age - 5011.3years) infected by H.pylori with known resistance to clarithromycin, metronidazole, and levofloxacin, but susceptibility to amoxicillin and tetracycline. All patients were previously submitted to upper endoscopy with gastric biopsies for H.pylori culture and susceptibility testing by Etest. Mutations in 23S rRNA and gyrA genes were determined by real-time PCR. A 10-day eradication regimen with PPI (double-standard dose b.i.d.), amoxicillin (1000mg b.i.d.), and doxycycline (100mg b.i.d.) was prescribed after pretreatment with PPI during 3days. Eradication success was assessed by C-13-urea breath test 6-10weeks after treatment. Compliance and adverse events were determined through phone contact immediately after treatment and specific written questionnaires. ResultsOnly one patient did not complete treatment due to adverse events. Another four patients experienced mild side effects not affecting compliance. The control C-13-urea breath test was positive in all patients. Per-protocol and intention-to-treat eradication rates were 0%. ConclusionsAlthough safe, a triple-therapy protocol with high-dose PPI, amoxicillin, and doxycycline is useless for multidrug-resistant H.pylori eradication.