The impact of antibiotic resistance on the efficacy of three 7-day regimens against Helicobacter pylori.
BACKGROUND
Antibiotic resistance affects the success of anti-Helicobacter pylori therapies and varies greatly from country to country.


OBJECTIVE
To compare the efficacy of three short-term triple regimens in relation to H. pylori primary resistance in our region.


METHODS
We enrolled 210 H. pylori-positive dyspeptic patients for this randomized, open, parallel-group study. Three arms of 70 patients each received the following 1-week regimens: (1) ranitidine bismuth citrate 400 mg b.d. + clarithromycin 250 mg b.d. + metronidazole 500 mg b.d. (RCM); (2) bismuth subcitrate 240 mg b.d. + amoxycillin 1000 mg b.d. + metronidazole 500 mg b.d. (BAM); (3) omeprazole 20 mg o.d. + clarithromycin 250 mg b.d. + metronidazole 500 mg b.d. (OCM). H. pylori was assessed by CLO-test and histology before and 4 weeks after therapy. Antibiotic resistance was assessed by E-test.


RESULTS
On intention-to-treat analysis RCM was more effective than OCM (84% vs. 69%; P < 0.03) and BAM (84% vs. 63%; P < 0.004). MIC determination was successful in 117 out of 210 patients (55%); metronidazole resistance was present in 52 out of 117 patients (44%) and clarithromycin resistance was present in 17 out of 117 patients (14%). Excellent cure rates were achieved when strains were sensitive to both antibiotics (100% with RCM and BAM and 90% with OCM), whereas RCM was superior to OCM (P=0.009) and BAM (P=0.001) with respect to overall resistant strains (94% vs. 57% and 38%, respectively).


CONCLUSIONS
One-week RCM is the best regimen to eradicate H. pylori in our geographical area. This seems to be linked to the better ability of RCM compared to OCM and BAM in overcoming the high prevalence of H. pylori resistance to both metronidazole and clarithromycin in our region.
Savarino
V
V
Department of Internal Medicine (DIMI), University of Genoa, Italy. vsarin@unige.it
Zentilin
P
P
Pivari
M
M
Bisso
G
G
Raffaella Mele
M
M
Bilardi
C
C
Borro
P
P
Dulbecco
P
P
Tessieri
L
L
Mansi
C
C
Borgonovo
G
G
De Salvo
L
L
Vigneri
S
S
D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001729:Bismuth / Q000494:pharmacology / Q000627:therapeutic use; D017291:Clarithromycin / Q000494:pharmacology / Q000627:therapeutic use; D004352:Drug Resistance, Microbial; D004359:Drug Therapy, Combination; D005260:Female; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects*; D006801:Humans; D008297:Male; D008795:Metronidazole / Q000494:pharmacology / Q000627:therapeutic use; D008875:Middle Aged; D011899:Ranitidine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents; D008795:Metronidazole; C073340:ranitidine bismuth citrate; D011899:Ranitidine; D017291:Clarithromycin; D001729:Bismuth