Impact of clarithromycin resistance on the effectiveness of a regimen for Helicobacter pylori: a prospective study of 1-week lansoprazole, amoxycillin and clarithromycin in active peptic ulcer.
BACKGROUND
Clarithromycin is a key antimicrobial in the combinations used to cure Helicobacter pylori infections, so there is a need to define the impact of in vitro resistance on in vivo results.


METHODS
A prospective trial was designed to study the effectiveness of the 1-week combination of lansoprazole, clarithromycin and amoxycillin in 102 consecutive patients with active peptic ulcer. The pre-treatment and post-treatment sensitivity to amoxycillin, metronidazole and clarithromycin were studied by E-test, and H. pylori status was defined by histology, culture and urease test at diagnosis and one month after treatment, and by urea-breath test 2 months after treatment.


RESULTS
The eradication rate (intention-to-treat analysis) was 77% (95% CI: 69-86). No clinical factor was found to be different between eradicated and non-eradicated patients. Clarithromycin-resistant strains were found in 10 (10%; CI: 5-17) patients. The eradication rate was 20% (CI: 3-56) in these patients vs. 83% (CI: 75-91) in patients harbouring clarithromycin-sensitive strains (P < 0.001). A logistic-regression analysis confirmed clarithromycin resistance as the only factor associated with treatment failure.


CONCLUSIONS
Clarithromycin resistance significatively impairs the effectiveness of the combination of lansoprazole, amoxycillin, and clarithromycin. The 80% efficacy goal will be difficult to reach in areas with high (>10%) primary clarithromyicin resistance, if currently recommended proton pump inhibitor-triple therapies are used.
Ducóns
J A
JA
Digestive Disease Service, Hospital San Jorge, Huesca, Spain.
Santolaria
S
S
Guirao
R
R
Ferrero
M
M
Montoro
M
M
Gomollón
F
F
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000328:Adult; D000368:Aged; D000658:Amoxicillin / Q000008:administration & dosage*; D017291:Clarithromycin / Q000008:administration & dosage*; D004352:Drug Resistance, Microbial; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy*; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D064747:Lansoprazole; D008297:Male; D008875:Middle Aged; D009853:Omeprazole / Q000008:administration & dosage / Q000031:analogs & derivatives*; D010437:Peptic Ulcer / Q000188:drug therapy*; D011446:Prospective Studies
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D064747:Lansoprazole; D000658:Amoxicillin; D017291:Clarithromycin; D009853:Omeprazole