The bla(CTX-M-1) gene located in a novel complex class I integron bearing an ISCR1 element in Escherichia coli isolates from Zhenjiang, China.

摘要

CTX-M enzymes include more than 60 variants belonging to five different clusters (CTX-M-1, CTX-M-2, CTX-M-8, CTX-M-9 and CTX-M-25) according to their amino acid sequence. In recent years, CTX-M enzymes have become the most prevalent extended-spectrum beta-lactamases (ESBLs), both in nosocomial and in community settings. Different genetic elements might be involved in the mobilization of bla_(CTx-M) genes, such as insertion sequences (ISs) ISEcpl, IS26 and IS903.1 The bla_(CTx-M) genes have also been associated with ISCR1 (ISs common region 1, previously also called orf513), which is embedded in class 1 integrons.