The minimum inhibitory and bactericidal concentrations of antibiotics and anti-ulcer agents against Campylobacter pyloridis.

The minimum inhibitory and bactericidal concentrations of twenty-two antibiotics, in liquid and solid media, and three anti-peptic ulcer drugs in liquid media were determined against twenty isolates of Campylobacter pyloridis. Camp. pyloridis was very susceptible to most antibiotics, more so than Camp. jejuni and Camp. fetus, but was resistant to nalidixic acid. The MIC90 of cimetidine against Camp. pyloridis was 512 mg/l, and of ranitidine was 6400 mg/l. The difference in susceptibility patterns between Camp. pyloridis and other campylobacters may indicate that Camp. pyloridis is not a member of the Campylobacter genus.