title: Phenomenon of resistance to Augmentin associated with sensitivity to ampicillin: occurrence and explanation.
abstract: Ampicillin was found to be some tenfold more active than amoxycillin against Enterobacter cloacae. This finding explains the observation that some Ent cloacae strains are sensitive to ampicillin in the disc test but resistant to Augmentin. Ampicillin was also found to be more active than amoxycillin against Citrobacter freundii and Serratia marcescens. In view of these findings, the practice of using ampicillin discs to predict sensitivity to amoxycillin should be reconsidered. The use of both ampicillin and amoxycillin discs is appropriate if errors are to be avoided.
mesh_terms: D000658:Amoxicillin / Q000494:pharmacology*; D019980:Amoxicillin-Potassium Clavulanate Combination; D000667:Ampicillin / Q000494:pharmacology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002954:Citrobacter / Q000187:drug effects; D002969:Clavulanic Acids / Q000494:pharmacology*; D004338:Drug Combinations / Q000494:pharmacology; D004754:Enterobacter / Q000187:drug effects; D004755:Enterobacteriaceae / Q000187:drug effects*; D008826:Microbial Sensitivity Tests / Q000379:methods; D010403:Penicillin Resistance; D012706:Serratia marcescens / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D002969:Clavulanic Acids; D004338:Drug Combinations; D019980:Amoxicillin-Potassium Clavulanate Combination; D000667:Ampicillin; D000658:Amoxicillin