with several bacterial strains , expecially if producers of beta-lactamase type iv , exposure of either the bacterial suspensions of the brothsupernatant to the isoxazolylpenicillins appears both in vivo and in vitro to reduce the extent of subsequent hydrolysis of penicillinase-sensitive beta-lactam antibiotics .
C0597979
beta-lactamase
C0030841
penicillinase