许多新的广谱头孢菌素在最近几年已被开发出来,在这些抗生素中有些已临床应用于较广范围的细菌感染,但这些抗生素抗革兰氏阳性菌较老的头孢菌素疗效要差。例如头孢噻肟(CTX)和头孢哌酮(CPZ)抗革兰氏阴性菌具有高的内在活性,但如能更进一步改善抗假单孢菌、沙雷氏菌和肠杆菌则更理想。Ceftazidime(CAZ)抗上述细菌活性高,但抗葡萄球菌则较CTX、CPZ活性低。这种情况激励人们对较新抗生素的寻 Many new broad-spectrum cephalosporins have been developed in recent years, and some of these antibiotics have been clinically applied to a wide range of bacterial infections, but the efficacy of these antibiotics against Gram-positive bacteria is greater for older cephalosporins difference. For example, cefotaxime (CTX) and cefoperazone (CPZ) have high intrinsic activity against Gram-negative bacteria, but are more desirable if they are to further improve against Pseudomonas, Serratia and Enterobacter. Ceftazidime (CAZ) is highly active against these bacteria but anti-staphylococci are less active than CTX and CPZ. This situation motivates people to look for newer antibiotics