舒巴坦和硫酸黄连素对禽大肠埃希氏杆菌超广谱β-内酰胺酶(ESBLs)的抑制作用

Inhibitory Effect of Sulbactum and Berberine on Extended-Spectrum β-Lactamases from E.colic in Fowl

对临床分离产ESBLs的禽源大肠埃希氏杆菌进行了体外抑菌试验,并利用分光光度法进行了酶动力学及酶抑制剂抑酶效应的研究.结果表明,头孢噻呋(CTF)对ESBLs的M IC值>128 mg.L-1,与舒巴坦(SBT)联用(m∶m=2∶1)后平均值降为12.7 mg.L-1,与硫酸黄连素(BBR)联用(m∶m=1∶1 000)后降为16 mg.L-1.SBT和BBR都可以降低ESBLs对CTF的水解;CTF与SBT不同配比(m∶m=2∶1,4∶1)对CTF的抑酶保护率平均值分别为94.4,93.0%,CTF与BBR配比(m∶m=1∶10)抑酶保护率平均值为90.8%;酶动力学方面,SBT,BBR与CTF配比的Km值有明显的升高,即酶与CTF的亲和力变小,Vm ax并没有明显的降低,Vm ax/Km(有效水解率)有明显的降低(P<0.05),CTF与SBT不同配比(m∶m=2∶1,4∶1)的Vm ax/Km(平均值)降为5.6,5.0 s-1,CTF与BBR配比(m∶m=1∶10)降为8.4 s-1,说明CTF与SBT不同配比(m∶m=2∶1,4∶1)间的抑酶效果没有明显差异(P>0.05),但BBR的抑酶效果低于SBT.

The experiment on minimal inhibitory concentration to E. colic which produce ESBLs were conducted. The kinetics of ESBLs and the inhibitory effect of β-Lactamases inhibitor were studied by using the method of ultraviolet spectrophotometry. The results showed that the MICs of ceftiofur （CTF） were both above 128 mg . L^-1 and reduced to 12.7 mg . L^-1 mixed with sulbactum（SBT） （CTF/SBT m： m =2：1 ） , 16 mg . L^-1 with Berberine（BBR） （ CTF/BBR m： m = 1 ： 1 000） ,which revealed that SBT and BBR could both diminish the hydrolysis of ESBLs to CTF. The average hydrolysis rate was 94.4% and 93.0% , respectinely when the mass proportion of CTF to SBT was 2：1 and 4：1 ,which was 90.8% when CTF was combined with BBR in the mass proportion of 1 ： 10. As to the kinetics, the Kms of CTF increased obviously when mixed with SBT and BBR, that is to say, the affinity of ESBLs to CTF became loose, while the Vmax （the ability of hydrolysis） didn＇ t lessen. And the Vmax/Km decreased remarkably（P 〈 0.05 ） , the average of which fell to 5.6, 5.0 s^-1 when CTF proportioned with SBT in m： m = 2：1 and 4：1,8.4 s^-1 with BBR in m： m = 1： 10, revealing that there were not significant difference between the inhibitory effect of SBT when its proportion on CTF was 2：1 and that of 4： 1, while the inhibitory effect of BBR was less than that of SBT.