(Not Eradicated)

Post-treatment susceptibility results
 
   S †
 I†
 R †
 No MIC
 
Susceptible† 182
 162
  4
 0
 2
 14
 
Intermediate† 1
 1
  0
 0
 0
 0
 
Resistant† 29
 13
  1
 0
 13
 2
 Includes only patients with pretreatment and post-treatment clarithromycin susceptibility test results
†
Susceptible (S) MIC ≤ 0.25 mcg/mL, Intermediate (I) MIC = 0.5 mcg/mL, Resistant (R) MIC ≥ 1.0 mcg/mL
Patients not eradicated of H.pylori following NEXIUM/amoxicillin/clarithromycin triple therapy will likely have clarithromycin resistant H.pylori isolates. Therefore, clarithromycin susceptibility testing should be done, when possible. Patients with clarithromycin resistant H.pylori should not be re-treated with a clarithromycin-containing regimen.

Amoxicillin Susceptibility Test Results and Clinical/Bacteriological Outcomes:

In the NEXIUM/amoxicillin/clarithromycin clinical trials, 83% (176/212) of the patients in the NEXIUM/amoxicillin/clarithromycin treatment group who had pretreatment amoxicillin susceptible MICs (≤ 0.25 mcg/mL) were eradicated of H.pylori, and 17% (36/212) were not eradicated of H. pylori. Of the 36 patients who were not eradicated of H. pylori on triple therapy, 16 had no post-treatment susceptibility test results and 20 had post-treatment H.pylori isolates with amoxicillin susceptible MICs. Fifteen of the patients who were not eradicated of H. pylori on triple therapy also had post-treatment H.pylori isolates with clarithromycin resistant MICs. There were no patients with H. pylori isolates who developed treatment emergent resistance to amoxicillin.

Susceptibility Test for Helicobacter pylori: The reference methodology for susceptibility testing of H.pylori is agar dilution MICs. One to three microliters of an inoculum equivalent to a No. 2 McFarland standard (1 x 107 - 1 x 108 CFU/mL for H.pylori) are inoculated directly onto freshly prepared antimicrobial containing Mueller-Hinton agar plates with 5% aged defibrinated sheep blood (≥ 2 weeks old). The agar dilution plates are incubated at 35°C in a microaerobic environment produced by a gas generating system suitable for Campylobacter. After 3 days of incubation, the MICs are recorded as the lowest concentration of antimicrobial agent required to inhibit growth of the organism. The clarithromycin and amoxicillin MIC values should be interpreted according to the following criteria:

Table 8

*
These are breakpoints for the agar dilution methodology and they should not be used to interpret results obtained using alternative methods.
†
There were not enou