在具有不同作用方式的抗生素中,β-内酰胺类抗生素因其选择性毒性,故曾是抗生素筛选的主要目标。在过去数十年中,已在真菌发酵液内发现了青霉素和头孢菌素等β-内酰胺类抗生素。自1971年发现了放线菌产生的头霉素(cephamycins)以来,诸如诺卡菌素(nocar-dicins)、碳青霉烯与克拉维酸之类具有新型骨架的β-内酰胺类抗生素,已发现均可由放线菌产生。最近报道了许多由细菌产生的β-内酰胺类抗生素,预计它们将会在临床上得到应用。另一方面,作为新抗筛选的检测系统,敏 Among antibiotics with different modes of action, β-lactam antibiotics have been the main target of antibiotic screening because of their selective toxicity. In the past few decades, β-lactam antibiotics such as penicillins and cephalosporins have been found in fungal fermentation broths. Since the discovery of actinomycete-producing cephamycins in 1971, β-lactam antibiotics with novel backbones such as nocar-dicins, carbapenems and clavulanic acid, It has been found that actinomycetes can be produced. Recently, many bacterial-producing β-lactam antibiotics have been reported and they are expected to find clinical application. On the other hand, as a new anti-screening test system, Min