Studies on Staphylococcal Penicillinase

Abstract

SUMMARYThe induction of penicillinase in Staphylococcus aureus resistant to benzyl penicillin has been investigated. Inducers tested included several new penicillins derived from 6-aminopenicillanic acid, benzyl penicillin amide and cephalosporin C. Fifteen strains of S . aureus were examined, one in detail and the others using only two or three inducers. All strains possessed basal penicillinase and all were inducible, although maximum enzyme levels varied somewhat from one strain to another.Hydrolysis of the penicillins by staphylococcal penicillinase was investigated by using supernatant fluid from a cephalosporin C-induced culture of Staphylococcus aureus 524 as the source of enzyme. Under these conditions all the penicillins except methicillin were inactivated, although a t different rates. Hydrolysis of methicillin was only detectable a t much higher enzyme concentrations. Hydrolysis of cephalosporin C was not observed.The use of penicillins for the treatment of staphylococcal infections is discussed in the light of these results.

Macrolide Resistance in Staphylococcus aureus : Induction of Macrolide-Resistant Protein Synthesis

“…Several aspects of EM resistance induction, including concentration of inducer required, the inhibitory effects of high concentrations of inducer, and the time course of induction, bear a resemblance to the induction of penicillinase in gram-positive bacteria (5,9,12,17). The induction of EM resistance follows saturation kinetics, and the time course is similar to that reported by Leggate and Holms (9) for penicillinase induction in S. aureus.…”

The cephalosporin antimicrobial agents: a comprehensive review

“…The @-lactamases produced by Grampositive bacteria are primarily penicillinases which are synthesized by the bacterial cell in large amounts and then transferred through the bacterial cell wall to the external surface of the organism and released into the surrounding environment. T h e production of these penicillinases is usually plasmid-mediated and may be increased (induced) by the presence of any @-lactam compound, including cephalosporins (Mandell & Sande, 1985;Swallow & Sneath, 1962).…”

The Genetic Determinant of Staphylococcal Penicillinase*

“…The fraction of the enzyme that is extracellular (given as 40 per cent here) has been found by Swallow and Sneath (1962) to vary from strain to strain, and Novick and Richmond (1965) have demonstrated that a genetic determinant of extracellularity is linked to the penicillinase locus. This will be discussed further.…”