RECOVERY OF BETA-LACTAMIC ANTIBIOTICS USING THE INHIBITOR BRL-42715 IN RESISTANT STRAINS

The effect of the inhibitor BRL 42715 [C-6-(N1-methyl-1,2,3-triazolylm ethylene)penem] on beta-lactamase from Shigella flexneri UCSF-129 was studied. This is a multiresistant bacterium which causes shigellosis. The MIC(90) for amoxycillin fell from 4,096 to 8 mu g/ml in the presen ce of 1 mu g/ml of BRL 42715. This value was compared with the MIC(90) for ampicillin in the presence of several inhibitors of beta-lactamas e, including BRL 42715. The synergism of amoxycillin plus this latter inhibitor lasted for at least 18 h. Accordingly amoxycillin plus BRL 4 2715 is suggested as an efficient drug for the inhibition of multiresi stant micro-organisms.