犊牛腹泻大肠杆菌K99株抗生素敏感性试验及中草药提取物体外抑菌试验

Antibiotic susceptibility test of Escherichia coli K99 strain leading to calf diarrhea and antibacterial test in vitro of Chinese herbal medicine extract

为了解河北地区地方流行株大肠杆菌(Escherichia coli)K99对15种抗生素和22味中草药提取液的敏感性,试验采用K-B纸片法测定15株大肠杆菌K99株对15种抗生素药物的敏感性,采用琼脂打孔法测定22味中草药水煎提取液对试验菌株的体外敏感程度,用微量二倍稀释平板法测定中草药提取液最小抑菌浓度(MIC)和最小杀菌浓度(MBC)。结果表明:15株大肠杆菌均具有多重耐药性,其中试验菌株对阿莫西林、多西环素、新霉素等11种抗生素耐药率高达100%,其他4种抗生素耐药率为60%~93%;22味中草药中乌梅、五倍子、五味子等10味中草药提取液对试验菌株有抑菌效果,其中乌梅的抑菌效果最佳。说明部分中草药对牛大肠杆菌K99株有较好的体外抑制效果,为临床应用抗生素和中草药治疗大肠杆菌所致犊牛腹泻病奠定基础。

In order to understand the susceptibility of Escherichia coli K99 strain which was prevalent in Hebei Province,to 15 kinds of antibiotics and 22 kinds of Chinese herbal medicine extracts,the K-B paper method in this test was used to determine the sensitivity of Escherichia coli K99 strain to 15 kinds of antibiotic drugs,and agar punching method was used to determine the in vitro sensitivity of 22 kinds of Chinese herbal medicine decoction extracts against the test strain;the minimum two-fold dilution plate method was used to determine the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of Chinese herbal extracts.The results showed that all 15 strains of Escherichia coli had multiple drug resistance.The drug resistance rates of the test strain to 11 antibiotics such as amoxicillin,doxycycline and neomycin were 100%,and the drug resistance rates to the other four antibiotics were 60%-93%.Among the 22 kinds of Chinese herbal medicines,10 kinds of Chinese herbal medicine extracts such as black plum,gallnut and schisandra had antibacterial effect on the test strain,among which black plum had the best antibacterial effect.The results suggested that some Chinese herbal medicine had good antibacterial effect against bovine Escherichia coli K99 strain in vitro,which laid a foundation for the clinical application of antibiotics and Chinese herbal medicine in the treatment of calf diarrhea caused by Escherichia coli.