EDTA对黏菌素体外抗菌活性的影响

Effects of EDTA on Antimicrobial Activity of Colistin in Vitro

采用微量肉汤稀释法研究了膜通透性促进剂EDTA对黏菌素体外抗菌活性的影响。结果表明:经PCR扩增,在受试的85株沙门菌和大肠杆菌菌株中,有23株检测到mcr-1基因,但未检出mcr-2~mcr-10阳性菌株;EDTA可增强除天然耐药的奇异变形杆菌和摩氏摩根菌以外的所有菌株(mcr-1阳性菌株、mcr-1阴性菌株和标准株)对黏菌素的敏感性,且增强黏菌素抗菌活性的作用随EDTA浓度的加大而增强;与60、30 mg/L的EDTA联用后,黏菌素对分离菌株的最小抑菌浓度(MICs)均显著降低,且沙门菌和大肠杆菌对黏菌素的耐药率均显著下降。因此,EDTA在≥30 mg/L的浓度下,可有效增强黏菌素对mcr-1阳性和mcr-1阴性菌株的抗菌活性。

The effects of EDTA on antimicrobial activity of colistin in vitro were studied by broth microdilution method.The results showed that 23 of 85 tested isolates were mcr-1-positive strains,while no mcr-2~mcr-10 positive strains were detected.EDTA could enhance the sensitivity of all strains to colistin including the mcr-1-positive,mcr-1-negetive isolates and the standard strain with the exception of Proteus mirabilis and Morganella morganii.Moreover,the antibacterial activity of colistin increased with the increase of EDTA concentration.After combined with 60 or 30 mg/L EDTA,The minimal inhibitory concentrations(MICs)of colistin against clinical isolates decreased significantly,and the drug resistance rate of Salmonella and Escherichia coli to colistin also decreased significantly.Thus,it could be seen that EDTA with a concentration of≥30 mg/L could effectively enhance the antibacterial activity of colistin against both mcr-1-positive and mcr-1-negative strains.