Antibiotic Resistance Monitoring and Reference Laboratory, Health Protection Agency-Colindale, London NW9 5EQ, UK.
J Antimicrob Chemother. 2013 Jan;68(1):153-8. doi: 10.1093/jac/dks350. Epub 2012 Sep 3.
ME1071 is a maleic acid that inhibits metallo-β-lactamases (MBLs). We examined its ability to potentiate different carbapenems against MBL-producing Enterobacteriaceae in relation to its inhibition kinetics.
Enterobacteriaceae and Acinetobacter isolates with IMP, VIM and NDM MBLs were tested; bacteria with other types of carbapenem resistance were used as controls. Chequerboard titrations were performed by CLSI agar dilution, carbapenemases were cloned into pET-28a(+) and purified by column chromatography, and kinetic parameters were determined by spectrophotometry.
The key findings were: (i) the MICs of carbapenems varied widely among isolates with the same carbapenemase, but those with the NDM types were generally the most resistant; (ii) biapenem was the carbapenem least compromised by all MBL types, owing to weaker kinetic efficiency (k(cat)/K(m)) for hydrolysis, contingent on lower affinity (higher K(m)); (iii) MBLs were the only carbapenemases inhibited by ME1071, confirming its specificity of action; and (iv) irrespective of the partner carbapenem, synergy with ME1071 was least for organisms with NDM MBLs and most for those with IMP types, correlating with ME1071 having weakest affinity (highest K(i)) for NDM-1 and strongest affinity for IMP-1.
ME1071 reduced the MICs of carbapenems for bacteria with NDM-1 enzyme though synergy was weaker than for bacteria with IMP and VIM metallo-enzymes; this correlated with ME1071 having weaker affinity for NDM-1 than IMP-1 and VIM-2. As the weakest MBL substrate carbapenem, biapenem was the easiest to protect.
ME1071 是一种马来酸，可抑制金属β-内酰胺酶（MBLs）。我们研究了它与抑制动力学有关的增强不同碳青霉烯类药物对产 MBL 的肠杆菌科细菌的能力。
检测了携带 IMP、VIM 和 NDM MBL 的肠杆菌科和不动杆菌分离株；将具有其他类型碳青霉烯类耐药性的细菌作为对照。采用 CLSI 琼脂稀释棋盘滴定法进行棋盘滴定，将碳青霉烯酶克隆到 pET-28a(+)中，并通过柱色谱法进行纯化，通过分光光度法测定动力学参数。
主要发现为：（i）具有相同碳青霉烯酶的分离株的碳青霉烯类药物 MIC 差异很大，但具有 NDM 型的分离株通常最具耐药性；（ii）biapenem 是所有 MBL 类型中受影响最小的碳青霉烯类药物，由于水解的动力学效率（k(cat)/K(m)）较弱，取决于较低的亲和力（较高的 K(m)）；（iii）MBLs 是唯一被 ME1071 抑制的碳青霉烯酶，证实了其作用的特异性；（iv）无论与哪种碳青霉烯类药物结合，与 ME1071 的协同作用对于具有 NDM MBL 的生物最少，而对于具有 IMP 类型的生物最多，这与 ME1071 对 NDM-1 的亲和力最弱（最高 K(i)）和对 IMP-1 的亲和力最强相关。
ME1071 降低了具有 NDM-1 酶的细菌的碳青霉烯类药物 MIC，尽管协同作用比具有 IMP 和 VIM 金属酶的细菌弱；这与 ME1071 对 NDM-1 的亲和力弱于 IMP-1 和 VIM-2 有关。作为最弱的 MBL 底物碳青霉烯类药物，biapenem 最容易被保护。
