Penicillinase Studies on L-Phase Variants, G-Phase Variants, and Reverted Strains of Staphylococcus aureus

Abstract

L-phase variants and small colony (G-phase) variants derived from penicillinaseproducing Staphylococcus aureus strains were tested for penicillinase (beta lactamase) production. A refined variation of the modified Gots test for penicillinase was used to demonstrate penicillinase synthesis. Penicillinase synthesis was reduced in L-phase variants and G-phase variants when compared to parental strains. After reversion of variants to vegetative stages had been induced, revertants were tested for production of penicillinase, coagulase, and alpha hemolysin, mannitol fermentation, and pigment production, and comparisons were made between parent and reverted vegetative forms. All revertants of G-phase variants retained penicillinase activity. Most revertants of L-phase variants showed reduction or loss of penicillinase activity. Retention of coagulase activity, alpha hemolysin production, mannitol fermentation, pigmentation, and phage type varied among revertants.

In Vivo Behavior of Revertants from Staphylococcus aureus L-Phase Variants Compared with the Parent Strain

“…There are, however, no data on the in vivo behavior of these revertants. It has been shown that microorganisms reverted in vitro from L-phase variants of S. aureus regardless of the inducing agent frequently lose several of the characteristics of the parent strain (8,11). The in vivo behavior of revertants from the L-phase variant of a virulent strain of S. aureus as compared with the parent strain is the subject of this investigation.…”