Related Experiment Video
Updated: Jun 9, 2026

Quantitative Polymerase Chain Reaction (qPCR)-Based Rapid Diagnosis of Helicobacter pylori Infection and Antibiotic Resistance
Published on: July 28, 2023
[Helicobacter pylori eradication in patients with peptic ulcer after two treatment failures: a prospective
Aim:
To determine the effectiveness of a third, culture-guided, treatment of H. pylori infection after two unsuccessful attempts.
Patients And Methods:
Forty-two consecutive patients with a diagnosis of peptic ulcer were included in an open prospective and multicenter study. After two unsuccessful attempts at eradication (demonstrated by positive urea breath test), all patients underwent endoscopy and H. pylori infection was confirmed by urease test, histology and culture (Pylori-Agar, Bio Merieux, France). Antibiotic susceptibility to metronidazole, amoxicillin, tetracycline and clarithromycin was defined by E-test. Thirty-nine patients received a two-week quadruple culture-guided therapy defined by the protocol, which considered sensitivity data and previous allergies to antibiotics (one culture was contaminated, one patient refused treatment and one was allergic to tetracycline and amoxicillin and was resistant to metronidazole and clarithromycin). Compliance was monitored by pill counting and eradication was defined as a negative urea breath test six weeks after the end of treatment.
Results:
Sensitivity data were obtained in 41 patients. Intention-to-treat analysis revealed that overall eradication was achieved in 60% (24/40). Eighteen strains (43.9%) were resistant to metronidazole, 21 (51.2%) were resistant to clarithromycin and 8 (19.5%) were resistant to both drugs. None of the strains were resistant to amoxicillin or tetracycline. We used mainly two kinds of quadruple therapy in the 39 patients. Despite good compliance with treatment based on omeprazole (20 mg/12 h), bismuth subcitrate (120 mg/6 h), tetracycline (500 mg/4 h) and clarithromycin (500 mg/ 12 h) (OBTC) eradication was achieved in only 9 of 19 patients (47.4%; CI: 24.4-71.1) (one patient failed to attend the urea breath test). Nineteen clarithromycin-resistant patients received amoxicillin (1,000 mg/12 h) instead of clarithromycin (OBTA) and this treatment was effective in 14 (73.7%; CI: 48.8-90.9). Eradication was achieved in one patient who was allergic to amoxicillin and resistant to clarithromycin and metronidazole and who received ciprofloxacin (500 mg/8 h) instead of clarithromycin (OBTCipro). No clinical factors associated with eradication failure were found.
Conclusions:
Despite the use of two-week, high-dose, quadruple and culture-guided combinations of drugs, a third treatment was frequently unsuccessful. The lowest eradication rate was obtained in patients with H. pylori strains sensitive to all antibiotics; therefore, we believe that other factors could influence eradication rates. New prospective and randomized studies are needed in this subgroup of patients to find effective treatments.
More Related Videos
05:23Gastric Mucosa Quantitative Polymerase Chain Reaction Analysis for Detecting Helicobacter pylori and Antibiotic Resistance
Published on: March 7, 2025
04:56Detection of Helicobacter pylori Infection and Antibiotic Resistance via Stool Quantitative Polymerase Chain Reaction Analysis
Published on: May 16, 2025
Related Concept Videos
Treating Helicobacter pylori in Peptic Ulcers: Antimicrobial Therapy
Peptic Ulcer Disease I: Introduction
An acute ulcer, marked by superficial erosion and minimal inflammation, swiftly resolves upon identifying and addressing the underlying cause. In contrast, a chronic ulcer persists, potentially eroding through the muscular wall and forming fibrous tissue.
Peptic ulcers can also be...
Peptic Ulcer Disease II: Pathophysiology
Damaging agents such as Helicobacter pylori, gastric acid, pepsin, and nonsteroidal anti-inflammatory drugs (NSAIDs) can weaken the mucosal defense, allowing hydrogen ions to infiltrate back and harm epithelial cells.
Peptic Ulcer Disease III: Clinical Manifestations and Diagnostic Studies
Few clinical manifestations differentiate gastric ulcers from duodenal ulcers. Distinctions in the location, timing, and pain relief are crucial for healthcare providers in differentiating between gastric and duodenal ulcers during clinical assessments.
Peptic Ulcer Disease IV: Management
The therapeutic approach involves ensuring adequate rest, implementing drug therapy, promoting smoking cessation, making dietary modifications, and emphasizing long-term follow-up care.
Pharmacological management
The prevailing therapy for peptic ulcers involves a combination of managing the patient's current medication...
Peptic Ulcer Disease II: Pathophysiology