Antibiotic accumulation assays for susceptible H. pylori ATCC 700392 and its transformed resistant H. pylori strain. Shown are accumulation patterns of chloramphenicol (A), penicillin (B), and tetracycline (C). Symbols: diamonds, susceptible H. pylori ATCC 700392; squares, one half of the transformed resistant H. pylori ATCC 700392, without treatment with 100 μM CCCP; triangles, the other half of the transformed resistant H. pylori ATCC 700392, with treatment with 100 μM CCCP at 20 min (arrows). Results are representative of five independent experiments.