Penicillinase Adaptation and Fixation of Penicillin Sulphur by Bacillus cereus Spores

Abstract

SUMMARY: In contrast to vegetative cells, Bacillus cereus spores do not react to treatment with penicillin by increased production of penicillinase when subsequently grown in a penicillin-free medium. Neither do spores show specific fixation of penicillin sulphur, with maximum absorption at 1.0 unit/ml., which is characteristic of vegetative cells. However, treatment of vegetative cells with penicillin shortly before or during sporulation leads to the formation of ‘adapted’ spores able to form penicillinase up to 10 times more rapidly than untreated spores when subsequently germinated and grown in a penicillin-free medium; and specific uptake of penicillin S on spore material occurs after mechanical disruption of the spore-wall. It is concluded that the fully mature and undamaged spore-casing is impermeable to penicillin.