The fact that Helicobacter pylori can revert to a coccoid form has sti
mulated speculation about its role in transmission and as a possible c
ause of reinfection in duodenal ulcer disease. Bismuth subcitrate (32
mug/ml), bismuth subsalicylate (64 mug/ml), amoxicillin (0.05 mug/ml)
and erythromycin (4 mug/ml) inhibited the growth of H. pylori and stim
ulated the formation of basically respiring but non-culturable coccoid
structures. The presence of polyphosphates as energy and phosphorus s
ource permits a certain level of endogenous metabolism to preserve RNA
and DNA, as well as structural components like cell wall, cell membra
ne and cytoplasma for at least 3 months. However, the applied standard
laboratory methods were insufficient for regrowth of H. pylori out of
the coccoid form.