Activity of 13 β-lactam agents combined with BRL 42715 against β-lactamase producing Gram-negative bacteria compared to combinations with clavulanic acid, tazobactam and sulbactam
The activity of six cephalosporins, six penicillins and one monobactam combined with BRL 42715, clavulanic acid, sulbactam or tazobactam at 0·1, 0·5, 1, 2, 5 and 10 mg/L was determined for 45 β-lactamase producing Gram-negative bacteria. The combination of BRL 42715 with any of the agents was more active than any of the other inhibitor and β-lactam combinations. Unlike the other β-lactamase inhibitors, BRL 42715 enhanced the activity of the β-lactams for strains that constitutively expressed Richmond & Sykes Class I β-lactamase and against strains expressing extended-spectrum plasmid-mediated β-lactamases.