Staphylococcal Penicillinase Characteristics of the Enzyme and Its Distribution

Abstract

Staphylococcal penicillinase was prepd. by treatment of the bacterial cells 1st with acetone, and then with ether at 20 C. Greater uniformity of results was attained than when extraction was carried out at room temp. Advantage was taken of the tact that this penicillinase could be quantitatively removed from suspension by passage through Seitz filters, to control the time of action of the enzyme. When the time of action of the enzyme on penicillin was controlled, it was found that its activity was regularly affected by temp., time, and quantity of enzyme and of substrate. Several prepns. from 1 strain of Staphylococcus gave quite uniform results. The penicillinase content of 40 strains of Staphylococcus was detd. 22 of them had no demonstrable quantity. 18 had from 190-125,000 arbitrary U./g. When a heavy inoculum of bacteria was used in testing the sensitivity of a strain to penicillin, good correlation was found between penicillin resistance and the penicillinase content, When a small inoculum was used, the correlation between penicillin resistance and penicillinase content largely disappeared.