[Influence of the autolytic system on the bactericidal effect induced by beta-lactamic antibiotics (author's transl)]

New experimental conditions showing the phenomena of "antibiotic tolerance" are described. In Streptococcus pneumoniae, a strong protection against the loss of viability induced by penicillin was obtained when TRIS (hydroxymethyl aminomethane), instead of potassium phosphate, was used as buffer of the growth medium. The main pneumococcal autolysin (N-acetyl-muramil amidase) present in S. pneumoniae was found to be, at least partially, responsible for the loss of viability induced by beta-lactamic molecules.