三种抗菌药物对仔猪黄白痢大肠杆菌MPC的测定

Mutant prevention concentrations of three antibacterial agents against Escherichia coli from piglet’s yellow-white dysentery

关键词:  仔猪黄白痢  大肠杆菌  环丙沙星  麻保沙星  多粘菌素B  MPC

Key words:  piglet’s yellow-white dysentery  Escherichia coli  ciprofloxacin  marbofloxacin  polymyxin B  MPC

摘要:

采用琼脂二倍稀释法使平板上接种细菌量分别为1.5×104CFU、1.2×1010CFU，测定环丙沙星、麻保沙星、多粘菌素B对仔猪黄白痢大肠杆菌的MIC、MPC，并计算SI（MPC/MIC）。试验结果表明，受试菌对多粘菌素B、麻保沙星、环丙沙星的敏感率分别为80.85%、 17.02%、12.76%，两种喹诺酮类药物已有交叉耐药产生；两种喹诺酮类药物对敏感菌的MPC为1～16μg/mL，SI为 4～32，多粘菌素B的MPC为4～16μg/mL，SI为2～8，因此认为多粘菌素B不仅抗菌活性较高，SI也低于环丙沙星、麻保沙星, 即多粘菌素B的防耐药突变能力比麻保沙星与环丙沙星要强。

Abstract:

The MICs and MPCs of ciprofloxacin, marbofloxacin, polymyxin B against Escherichia coli from piglet’s yellow-white dysentery were determined using the agar doubling dilution method with an inoculum of 1.5×104 CFU, 1.2×1010 CFU, respectively. The results showed that the sensitivity rate of polymyxin B, ciprofloxacin and marbofloxacin was 80.85%, 17.02% and 12.76%, and cross resistance between ciprofloxacin and marbofloxacin was encountered. Comparing with 1-16μg/mL of the MPC and 4-32 of the SI (MPC/MIC) of the two quinolones to the sensitive strains, the MPC of polymyxin B and its SI was 4-16μg/mL and 2-8. Therefore, it was concluded that polymyxin B has relative strong antibacterial activity against the clinical isolates; it also exhibited a smaller SI. The capacity of polymyxin B for restricting the selection of E. coli resistant mutants was greater than that of ciprofloxacin and marbofloxacin.