[Resistance of acylase-forming strains of E. coli to penicillin]

The role of penicillinacylase in resistance to penicillin of various strains of E. coli differing in the levels of acylase produced was investigated. All the strains produced simultaneously acylase and beta-lactamase. A preparation of pure acylase and an antiacylase immune serum were used in the experiments. The sensitivity testing was accompanied by chromatography of the culture broth with a purpose of finding penicillin inactivation products. A principle possibility of increasing the culture resistance to penicillin under the action of acylase was found. However, in testing the strain sensitivity with a method of serial dilutions the conditions for synthesis and action of acylase were unfavorable. Therefore, the main factor of the culture resistance to penicillin was beta-lactamase and not acylase.