SYNERGISTIC EFFECT OF AMPICILLIN AND DICLOXACILLIN ON PATHOGENIC BACTERIA. I

In vitro Synergism

Abstract

A synergistic effect of ampicillin and dicloxacillin on pathogenic bacteria has been studied in vitro.
Growth of the high penicillin resistant bacteria, namely, E. coli strain 0205, Proteus morganii and Enterobacter aerogenes were inhibited with the relatively low concentrations of the mixture of ampicillin and dicloxacillin.
This synergism can be explained by the fact that dicloxacillin inhibits the enzymatic hydrolysis of ampicillin by β-lactamase prepared from these bacteria, particularly, strong inhibition was observed against enzymes have a relatively slow hydrolysis rate for ampicillin.