Edwards J R, Turner P J
Zeneca Pharmaceuticals, Macclesfield, Cheshire, UK.
Scand J Infect Dis Suppl. 1995;96:5-10.
Meropenem and imipenem are carbapenems which are distinguishable from all other currently available beta-lactam antibiotics by breadth of antibacterial spectrum and stability to beta-lactamases, but can be differentiated one from another. Meropenem is relatively stable to human renal dehydropeptidase-I (DHP-I); it does not require to be co-administered with cilastatin and consequently, unlike imipenem, will be administered as a single agent. In vitro both meropenem and imipenem are active against almost all clinically important aerobic and anaerobic bacteria. Differences in potency are seen but few may be of clinical significance: imipenem is more active against enterococci and meropenem is more active against Pseudomonas aeruginosa, Pseudomonas cepacia, Haemophilus influenzae and Proteus, Morganella and Providencia species. The primary target of imipenem is PBP2 in P. aeruginosa whilst meropenem has high affinity for both PBP2 and 3; this may contribute to greater potency against this organism. Laboratory evaluations predict that meropenem will not be seizurogenic, which combined with activity against likely pathogens, identified its potential for the treatment of bacterial meningitis. This has been investigated in a guinea-pig model in which meropenem exhibited potent activity against the common meningeal pathogens and also infections caused by penicillin-resistant Streptococcus pneumoniae or Listeria monocytogenes. Clinical experience will determine the significance of these differences.
美罗培南和亚胺培南均为碳青霉烯类抗生素，它们在抗菌谱广度和对β-内酰胺酶的稳定性方面有别于目前所有其他可用的β-内酰胺类抗生素，但彼此之间也存在差异。美罗培南对人肾脱氢肽酶-I（DHP-I）相对稳定；它无需与西司他丁联合使用，因此，与亚胺培南不同，它将作为单一药物给药。在体外，美罗培南和亚胺培南对几乎所有临床上重要的需氧菌和厌氧菌均有活性。虽然可以看到两者在效力上存在差异，但很少有差异具有临床意义：亚胺培南对肠球菌的活性更强，而美罗培南对铜绿假单胞菌、洋葱伯克霍尔德菌、流感嗜血杆菌以及变形杆菌属、摩根菌属和普罗威登斯菌属的活性更强。亚胺培南在铜绿假单胞菌中的主要靶点是PBP2，而美罗培南对PBP2和PBP3均具有高亲和力；这可能有助于其对该菌具有更强的效力。实验室评估预测美罗培南不会诱发癫痫，再加上它对可能的病原体具有活性，这确定了其在治疗细菌性脑膜炎方面的潜力。这一点已在豚鼠模型中得到研究，在该模型中美罗培南对常见的脑膜病原体以及由耐青霉素肺炎链球菌或单核细胞增生李斯特菌引起的感染均表现出强效活性。这些差异的意义将由临床经验来确定。
