Sensitivity of amoxicillin-resistant Helicobacter pylori to other penicillins

The sensitivities to penicillins and to a penicillin and beta-lactamase inh ibitor combination agent were determined for Helicobacter pylori strains th at were sensitive, moderately resistant, or highly resistant to amoxicillin . All strains were resistant to nafcillin and oxacillin. Moderately resista nt strains showed an intermediate zone of inhibition to ticarcillin, mezloc illin, piperacillin, and amoxicillin-clavulanic acid. High-level resistance was associated with the smallest zone size for all penicillins tested.