The in vitro intracellular effect of clarithromycin, amoxicillin, metronida
zole, lansoprazole, and rifabutin, tested at concentrations corresponding t
o one times the MIG, two times the MIG, and four times the MIG, was evaluat
ed against an invasive Helicobacter pylori strain. At four times the MIG, c
larithromycin showed an early bactericidal effect within 4 h of incubation
and, in determining the complete killing within a 16 h-incubation period, l
ansoprazole and rifabutin showed comparable activity, yielding bactericidal
activities within 4 and 8 h of incubation, respectively. Amoxicillin and m
etronidazole showed bacteriostatic activity only.