12种β—内酰胺类抗生素对β—内酰胺酶的稳定性研究

实验采用紫外分光光度法测定了(1)11株国际标准产酶菌的β—内酰胺酶活性;(2)11种β—内酰胺酶对12种β—内酰胺类抗生素的相对水解率;(3)CP—45899对11种酶的抑酶率。结果表明:酶K—1和TEM—2活性分别为699和319单位外,其余酶活性在22—72单位之间。12种抗生素中,第三代头孢菌素(除CPZ外)的酶稳定性最好;第二代头孢菌素中CXM的酶稳定性明显优于CMD和CPZ(P<0.01)。第一代头孢菌素和青霉素类易被酶水解。CP—458991ug/ml对多种β—内酰胺酶显示抑制作用,对CRD、CMD具有保护作用。

A STUDY ON THE STABILITY OF 12 β—LACTAM ANTIBIOTICS TO β—LACTAMASES

Activities of 11 ;β—lactamases(CRD used as the substrate), the stability of 12 β—lactam antibiotics to 11 β—lactamases and β—lactamases inhibited by CP45899 were determined by ultraviolet spectroph—otometry. The results of experiment revealed that activies of chromsome—mediated β—lactaatase K-1 and plasmid—mediated β—lactamase TEM—2 were relatively higy,being 699U and 319U respectively, while those of other β—lactamases were usually low,in the range of 22—72U. with exception of CPZ, the third generations of cephalos—porins CTZ, CET, were very stable to β—lactamases in 12 tested β—lactam antibiotics. The stability of the second generation of cephalosporins CXM to β—lactamases was significantly superior to that of CMD and CPZ (p<0.01), whereas the first generations of cephalosporins CPT, CRD and penicillins PCG, ABPC,CBPC and MCIPC were easily hydrolyzed by β—lactamases. CP—45899 possess good inhibitory action on the plasmid—mediated β—lactamases, and the combination of CRD or CMD and CP—45899 may produce synergic effect on producing—enzyme resistant bacterial.