Bush K
Astra Research Center Boston, Cambridge, Massachusetts, USA.
Clin Infect Dis. 1998 Aug;27 Suppl 1:S48-53. doi: 10.1086/514922.
Metallo-beta-lactamases have recently become more prominent among the beta-lactam-hydrolyzing enzymes. Two major functional groups of enzymes have been identified, with little structural similarity among the groups. One group is a set of enzymes with broad substrate specificities capable of hydrolyzing most beta-lactams except monobactams. A second group is composed of the "true" carbapenemases, enzymes that exhibit poor hydrolysis of penicillins and cephalosporins. This latter group has been found primarily in Aeromonas species. To date, only a small number of carbapenem-resistant isolates have been reported to produce metallo-beta-lactamases, in part because of the ease with which this resistance can be acquired by other means: permeability changes and an increase in chromosomal cephalosporinase production. However, the appearance of these enzymes on plasmids in Japan poses a worrisome problem. It is anticipated that plasmid-mediated resistance to carbapenems will continue to increase, perhaps compromising the use of these agents.
金属β-内酰胺酶最近在β-内酰胺水解酶中变得更加突出。已经鉴定出两大类功能酶，它们之间几乎没有结构相似性。一组是具有广泛底物特异性的酶，能够水解除单环β-内酰胺类之外的大多数β-内酰胺类。第二组由“真正的”碳青霉烯酶组成，这类酶对青霉素和头孢菌素的水解能力较差。后一组主要在气单胞菌属中发现。迄今为止，仅有少数耐碳青霉烯类分离株被报道可产生金属β-内酰胺酶，部分原因是这种耐药性可通过其他方式轻易获得，如通透性改变和染色体头孢菌素酶产生增加。然而，这些酶在日本质粒上的出现带来了一个令人担忧的问题。预计质粒介导的对碳青霉烯类的耐药性将继续增加，这可能会影响这些药物的使用。
