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为研究头孢噻肟-恩诺沙星联合用药对携带F17毒力基因牛源性大肠埃希氏菌(E.coli)耐药突变选择窗的影响,采用琼脂二倍稀释法测定头孢噻肟(CTX)和恩诺沙星(ENR)对11株携带F17毒力基因E.coli分离株单独用药及联合用药的最低抑菌浓度(MIC)、耐药突变度(MPC),计算耐药指数(SI)。结果显示,CTX和ENR联合用药后,CTX的MPC_(90)降至256 mg/L,SI下降了4倍,MPC_(90)/MIC_(90)为1,即联合ENR后能使CTX的耐药突变选择窗(MSW)完全关闭;同样联合用药后ENR的MPC_(90)降至256 mg/L,SI下降了2倍,MPC_(90)/MIC_(90)为2,MSW变窄,即联合CTX后能使ENR的MSW减小。结果表明,CTX联合ENR能够缩小甚至关闭其单药的MSW,有效防止耐药的产生。本研究为E.coli的耐药性防止提供了新思路,同时也为指导临床用药提供了新的思路。
In order to study the effect of cefotaxime / enrofloxacin combination on the selection window of the resistance mutation of F17 virulent Escherichia coli (E.coli), the double dilution of agar was used to determine the effect of cefotaxime CTX) and enrofloxacin (ENR) were used to determine the minimum inhibitory concentration (MIC) and drug resistance mutation (MPC) of 11 strains of E.coli isolates carrying F17 virulence, SI). The results showed that CTX reduced the MPC 90 to 256 mg / L, decreased the SI 4-fold and the MPC 90 / MIC 90 to 1 after combination of CTX and ENR. (MSW) of the ENR decreased to 256 mg / L, the SI decreased 2-fold, the MPC 90 / MIC 90 decreased to 2 and the MSW narrowed The combination of CTX reduces the MSW of ENR. The results show that CTX combined with ENR can reduce or even shut down its single drug MSW, effectively prevent the generation of drug resistance. This study provides a new idea for the prevention of drug resistance in E. coli, and also provides a new idea for guiding clinical drug use.