Observations on the Mechanism of Action of Penicillin.

TLDR

Penicillin can act as either a bacteriostatic or bactericidal agent depending on experimental conditions. Penicillin reduces bacterial counts at a constant rate, achieving 99 % kill, with the rate varying among species; it does not lyse hemolytic streptococci, is not metabolized by bacteria, and requires active bacterial growth to be effective.

Abstract

SummaryPenicillin acts either as a bacteriostatic or bactericidal agent depending on the experimental conditions. The number of organisms decreases at a constant rate until 99% of the organisms have been destroyed. The rate of killing varies with different organisms. The action of penicillin on hemolytic streptococci is not accompanied by lysis of the organisms. No detectable amount of penicillin is destroyed or absorbed from solution by the organisms. It appears to be effective only when active multiplication takes place.