为了寻找替代抗生素的促生长物质预防畜禽大肠杆菌病,能有效地利用我国丰富的植物资源,在不同的季节采集当地常见的孝顺竹竹叶提取有效成分,同时从患乳房炎奶牛的乳汁中和患大肠杆菌的病猪心、肝等组织中分离出致病性强、对抗生素耐药的大肠杆菌,对其进行抑菌试验。结果显示:不同季节采集的竹叶水提物对大肠杆菌具有不同的抑制作用,春季最大抑菌圈为17 mm,MIC为3.125 mg·mL-1,MBC为6.25 mg·mL-1;夏季最大抑菌圈为15 mm,MIC为3.125 mg·mL-1,MBC为6.25 mg·mL-1;秋季抑菌圈最大为12 mm,MIC 为6.25~12.50 mg·mL-1,MBC为12.5~25.0 mg·mL-1;冬季最大抑菌圈为20 mm,MIC 1.56 mg·mL-1,MBC为3.125 mg·mL-1。抗生素耐药的菌株对竹叶提取物敏感程度,不同季节的竹叶提取物对大肠杆菌抑制效果强弱为:冬季>春季>夏季>秋季。
In order to find an alternative antibiotic growth-promoting substances to prevent live-stock Escherichia coli disease,which can effectively utilize our abundant plant resources,we have collected active ingredients from common Bambua in different seasons,and isolated Esche-richia coli which is virulent and antibiotic-resistant in milk from cows suffering from mastitis and from the heart,liver and other tissues of pigs suffering from Escherichia coli.We have an-tibacterial test.The results show that the bamboo leaf water extracts of Escherichia coli in dif-ferent seasons have different inhibitory effect.The maximum inhibition zone is 1 7 mm,with MIC 3.125 mg·mL-1 and MBC 6.25 mg·mL-1 in spring;the maximum inhibition zone of 15 mm,with MIC 3.125 mg·mL-1 and MBC 6.25 mg·mL-1 in summer;the maximum inhibition zone is 12 mm,with MIC 6.25~12.5 mg·mL-1 and MBC 12.5~25.0 mg·mL-1 in autumn;the maximum inhibitory area is 20 mm,with MIC 1.56 mg·mL-1 and MBC 3.125 mg·mL-1 in winter.Antibiotic-resistant strains are sensitive to bamboo leaf extract.Bamboo leaf extracts in different seasons have different inhibitory effects on Escherichia coli ranked as:winter> spring> summer> autumn.