In vitro susceptibility of Helicobacter pylori to, and in vivo suppression by, antimicrobials used in selective decontamination of the digestive tract.

The incidence of bleeding related to stress ulcers is reduced in critically ill patients in whom gut decontamination has been performed; this may be a result of suppression of Helicobacter pylori infection. We determined the susceptibility of H. pylori to the applied antibiotics. In nine of 10 critically ill patients (using intravenous cefotaxime and topical polymyxin, tobramycin and amphotericin B (PTA) given by nasogastric tube) and all six volunteers (using PTA alone), H. pylori was suppressed as long as the topical antibiotics were ingested. The in vitro studies revealed that all strains were susceptible to cefotaxime and tobramycin. The strains were not susceptible to polymyxin or amphotericin B.