In Vivo Studies on Staphylococcal Penicillinase.

Eyckmans, Luc (Baylor University Medical Center, Dallas, Tex.), and Ralph Tompsett. In vivo studies on staphylococcal penicillinase. J. Bacteriol. 90:589-593. 1965.-The amounts of staphylococcal penicillinase present in tissue of mice with well-established infections due to penicillin-resistant staphylococci were determined. The data indicate that, in the presence of such infection, penicillinase can be found in amounts adequate to destroy large amounts of penicillin. These results are found in the absence of any conditions which are known to induce penicillinase. Although it has been generally assumed that penicillinase does account for the penicillin resistance of certain staphylococci in vivo, the data presented here document the quantitative aspects of this phenomenon, and indicate that the amounts of penicillinase produced are sufficient to account for the high degrees of resistance observed.