近年来 ,由于第三代头孢菌素的广泛应用选择性出现革兰阴性杆菌对 β内酰胺类抗生素的耐药 ,使细菌耐药趋势日趋严峻 ,成为医学界备受关注的问题。革兰阴性肝菌中 ,β内酰胺类抗生素的耐药性主要由临床上最重要的两类 β内酰胺酶引起 ,即高水平表达的染色体编码的ＡｍｐＣβ内 In recent years, due to the extensive use of the third generation cephalosporins, Gram-negative bacilli are selectively resistant to β-lactam antibiotics, making the bacterial resistance trend become more and more serious, which has become a concern in the medical field. Among gram-negative liver bacteria, the resistance of beta-lactam antibiotics is mainly caused by two clinically most important two types of beta-lactamases, namely, the high-level expression of chromosomally-encoded AmpCβ