Activity of the β-lactamase inhibitor BRL 42715 against cephalosporinases produced by Enterobacteriaceae

BRL 42715, a novel beta-lactamase inhibitor, was evaluated for its capacity to inhibit cephalosporinases. BRL 42715 was effective in potentiating the activity of antibiotics against clinical isolates of Enterobacteriaceae that produced high levels of cephalosporinases. This correlated well with the very low 50% inhibition values (< 0.004 mg/L) of BRL 42715 for cephalosporinases extracted from different species. When compared in vitro to clavulanic acid, sulbactam, and tazobactam, BRL 42715 was the most efficient inhibitor of cephalosporinase.