Clarithromycin-resistant genotypes and eradication of Helicobacter pylori.
BACKGROUND
Three point mutations (A2143G, A2142G, and A2142C) have been involved in Helicobacter pylori clarithromycin resistance.


OBJECTIVE
To compare the eradication rates among the different point mutations and the efficacy of triple therapy and a sequential regimen according to genotypic resistance.


METHODS
Post hoc subgroup study from a multicenter, randomized trial.


METHODS
Two hospitals in central and southern Italy between January and December 2001.


METHODS
156 patients with H. pylori infection.


METHODS
Real-time polymerase chain reaction for assessing clarithromycin resistance; histology, rapid urease test, and 13C-urea breath test at entry and after 4 to 6 weeks.


METHODS
7-day triple therapy (20 mg of rabeprazole, 500 mg of clarithromycin, and 1 g of amoxicillin) in 75 patients or a 10-day sequential regimen (20 mg of rabeprazole plus 1 g of amoxicillin for 5 days and 20 mg of rabeprazole, 500 mg of clarithromycin, and 500 mg of tinidazole for the remaining 5 days) in 81 patients. All drugs were given twice daily.


RESULTS
Helicobacter pylori infection was eradicated in 11 of 23 patients (48%) with the A2143G mutation and in 14 of 15 patients (93%) with either A2142G or A2142C strains (difference, 45 percentage points [95% CI, 15 to 65 percentage points]; P = 0.004). The sequential regimen achieved a higher cure rate than triple therapy in A2143G mutate strains (difference, 49 percentage points [CI, 8 to 72 percentage points]; P = 0.024).


CONCLUSIONS
The post hoc substudy design may require further confirmation. Other limitations are the accessibility to the tool and the cost of investigations (70 euros per patient).


CONCLUSIONS
The A2143G mutation seemed to be associated with a very low eradication rate. The sequential regimen achieved a higher cure rate than standard therapy even in patients with these strains.
De Francesco
Vincenzo
V
Ospedali Riuniti and University of Foggia, Foggia, Italy.
Margiotta
Marcella
M
Zullo
Angelo
A
Hassan
Cesare
C
Troiani
Laura
L
Burattini
Osvaldo
O
Stella
Francesca
F
Di Leo
Alfredo
A
Russo
Francesco
F
Marangi
Stefania
S
Monno
Rosa
R
Stoppino
Vincenzo
V
Morini
Sergio
S
Panella
Carmine
C
Ierardi
Enzo
E
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000658:Amoxicillin / Q000008:administration & dosage*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001562:Benzimidazoles / Q000008:administration & dosage*; D017291:Clarithromycin / Q000008:administration & dosage*; D024881:Drug Resistance, Bacterial; D004359:Drug Therapy, Combination; D005838:Genotype; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000382:microbiology; D016480:Helicobacter pylori / Q000187:drug effects* / Q000235:genetics*; D006801:Humans; D009853:Omeprazole / Q000008:administration & dosage / Q000031:analogs & derivatives*; D017354:Point Mutation; D064750:Rabeprazole; D016896:Treatment Outcome
D053799:2-Pyridinylmethylsulfinylbenzimidazoles; D000900:Anti-Bacterial Agents; D001562:Benzimidazoles; D064750:Rabeprazole; D000658:Amoxicillin; D017291:Clarithromycin; D009853:Omeprazole