Staphylopenicillinase—Its role in penicillin resistance: I. In vitro biological characterization of staphylopenicillinase

Abstract

<h2>Summary</h2> The in vitro characterization of the etheracetone sediment of Staphylococcus aureus (Giorgio) revealed that this material was high in penicillinase activity and that it was heat labile. However, no hemolysin, leukocidin or coagulase enzymes were demonstrated. Penicillinase was produced rapidly in vitro by viable staphylococci which were penicillin resistant. Peak production was achieved in 48 to 72 hours, after which the amount remained constant. The rate of production could be stimulated in the first few hours by the addition of small amounts of penicillin to the system. Each penicillin-resistant strain of Staphylococcus aureus tested produced penicillinase, and the amounts were consistently reproducible for each strain and characteristic of that strain. The amount of penicillinase produced did not accurately parallel the degree of penicillin resistance in vitro as determined by tube dilution sensitivity tests.