Evaluation of antibiotic treatment against "Candidatus Helicobacter suis" in a mouse model.

"Helicobacter heilmannii" (proposed name) type 1 colonizes the human stomach. It has been shown to be identical to "Candidatus Helicobacter suis," a Helicobacter species colonizing the stomachs of >60% of slaughter pigs. This bacterium has not been isolated in vitro until now. Antibiotic susceptibility testing of "Candidatus Helicobacter suis" has not been carried out so far. For the present study, a mouse model was adopted to evaluate the antibiotic susceptibility of this organism. Mice infected with "Candidatus Helicobacter suis" were treated with amoxicillin and omeprazole, a therapy which is used to treat H. heilmannii infections in humans. Two different isolates of "Candidatus Helicobacter suis" were tested. The excretion of bacterial DNA was assessed during treatment, using PCR on fecal samples. At the end of the experiment, 8 days after the cessation of treatment, the presence of infection was evaluated using a urease test and a PCR test on stomach samples. A marked decrease in the excretion of bacterial DNA was observed a few days after the onset of treatment, and the level remained low until the end of the experiment. A difference in susceptibility between the two "Candidatus Helicobacter suis" isolates was pointed out. The in vivo mouse model infected with "Candidatus Helicobacter suis" will be useful for further screening of potential therapeutic regimens.