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AmpCβ-内酰胺酶(AmpC)存在于大多数革兰阴性杆菌中,主要由染色体介导,在缺乏β-内酰胺类抗生素时,只产生少量的β-内酰胺酶,但在β-内酰胺类抗生素诱导剂存在时,AmpC酶的产量明显增加,导致对第三代头孢菌素耐药,目前认为AmpC酶的诱导调节机理与ampR、ampG、ampD有关;而大肠埃希菌缺乏调节基因ampR,AmpC酶不被诱导,但可以通过ampC启动子和衰减子突变导致高产AmpC酶。此外,质粒介导AmpC酶是近年来出现的新的耐药机制,同样可导致细菌广泛性耐药。
AmpC beta-lactamase (AmpC) is present in most Gram-negative bacilli and is mainly chromosomally mediated. In the absence of beta-lactam antibiotics, only a small amount of beta-lactamase is produced, but in beta-lactams In the presence of an antibiotic-inducing agent, the yield of AmpC enzyme is significantly increased, leading to drug resistance to the third generation cephalosporins. At present, it is believed that the mechanism of induction of AmpC enzyme is related to ampR, ampG, ampD, while Escherichia coli lacks ampR , AmpC enzymes are not induced, but high-yield AmpC enzymes can be induced by the ampC promoter and attenuator mutations. In addition, plasmid-mediated AmpC enzyme is a new drug resistance mechanism that has emerged in recent years, and can also lead to the widespread resistance of bacteria.