The in vitro activity of amoxycillin with clavulanic acid against clinically significant bacteria. A multicentre study.

A multicentre study to evaluate the activity of amoxycillin when combined with clavulanic acid against clinical bacterial isolates was performed in South Africa. Minimum inhibitory concentrations for amoxycillin alone and in combination with clavulanic acid were determined by agar dilution. The majority of amoxycillin-resistant Klebsiella and Escherichia coli strains became sensitive to amoxycillin in the presence of low concentrations of clavulanic acid. Beta-lactamase-producing strains of Staphylococcus aureus showed increased susceptibility to amoxycillin in the presence of clavulanic acid. Minimum bactericidal concentrations indicated that amoxycillin retains bactericidal activity in the presence of clavulanic acid. Enterobacter and Serratia species and Pseudomonas aeruginosa remained amoxycillin-resistant in the presence of clavulanic acid.