a collection of 98 strains of enteric gramnegative bacteria isolated in routine investigations in a hospital laboratory all showed beta-lactamase activity , and 39 of them ( 40 % ) produced sufficient enzyme to allow determination of their relative activities against benzylpenicillin , ampicillin and cephaloridine ( substrate profiles ) .
C0030827
benzylpenicillin
C0002680
ampicillin