钙通道阻断剂维拉帕米对耐恩诺沙星大肠杆菌的体外增敏试验

为评价钙通道阻断剂维拉帕米对耐抗菌药物恩诺沙星鸡源大肠杆菌体外增敏作用,采用试管倍比稀释法测定恩诺沙星、维拉帕米对临床分离的耐恩诺沙星、非耐恩诺沙星、标准大肠杆菌O2和O78共96株菌的最小抑菌质量浓度;恩诺沙星与维拉帕米联合药敏试验采用试管棋盘法,用部分抑菌浓度指数判断增敏效果。结果表明:维拉帕米单独使用对96株菌的最小抑菌质量浓度值均大于640μg/mL;维拉帕米与恩诺沙星联用后对77株耐恩诺沙星大肠杆菌中20株表现为协同作用,46株表现为相加作用;对其余11株临床耐药菌、17株临床敏感菌和2株标准敏感菌表现为无关作用,拮抗作用的为零。说明维拉帕米本身无抗菌活性,但对耐恩诺沙星鸡源大肠杆菌的耐药性具有一定程度的增敏作用。

Effect of verapamil on the resistance of enrofloxacin-resistant Escherichia coli in vitro

The objective of this study was to determine the effect of verapamil on the activities of enrifloxacin against enrofloxacin-resistant Escherichia coli in-vitro.The minimal inhibitory concentrations(MICs) of enrofloxacin and verapamil on 96 strains of E.coli(including standard O2,O78) were tested with the method of broth two-fold dilution.Then the check-board system was used to determine the fractional inhibitory concentration(FIC) index of enrofloxacin combined with verapamil.The combined sensitivity test indicated that the synergic effect was 26%(20/77),addition effect was 60%(46/77) and indifferent effect was 14%(11/77) of enrofloxacin-risistant E.coli.The indifferent effect was alsoobserved in all enrofloxacin-sensitiv strains(including two standard O2,O78).No antagonistic effect was found in vitro.Verapamil can reduce the resistance of E.coli to enrofloxacin in vitro.The MICs of verapamil against 96 E.coli strains revealed that the efflux pump inhibitor had little effect on the E.coli itself.