[Indicator method of determining the beta-lactamase-inhibiting activity of various compounds].

: An indicator for determination of beta-lactamase inhibitory activity of various compounds was developed. The method is based on the direct contact of beta-lactamase with the compounds tested. It excludes the use of test-bacteria and provides recording in the data on the day of the experiment. The indicator method enables the detection of the beta-lactamase inhibitory properties of both beta-lactamase inhibitors and beta-lactam antibiotics, not subjected to destruction by beta-lactamases. The method is likely to be fit for detection of atypical beta-lactams having beta-lactam groups in their molecules (bleomycin group). Antibiotics not belonging to the group of beta-lactams, such as gentamicin, sisomicin, lincomycin and fusidin showed no beta-lactamase inhibitory activity under the conditions of the indicator method. The use of the indicator method provided determination of the inhibitory activity with respect to penicillinase of Bac. licheniformis 749/C in 30 (8.5 per cent) out of 350 fermentation broths of actinomycetes.