某牛场奶牛产后败血症的细菌分离鉴定与药敏试验

Isolation,Identification and Drug Sensitivity Test of Bacteria Causing Dairy Cow Postpartum Septicemia in a Dairy Cow Farm

某牧场母牛产后发生体温升高、呼吸困难、乳汁中带血等症状,发病牛衰竭死亡,针对此种情况,采取病死牛的心脏、肝脏、子宫、乳汁等进行病原菌的分离和纯化,对其进行16S rRNA测序鉴定,毒力基因检测,致病性试验和药敏试验,还对牛的饮用水进行细菌数量的检测。结果显示,致病菌为大肠埃希氏菌、沙雷氏菌和产色葡萄球菌。在毒力基因检测试验中,从病料及饮用水分离出的20株大肠埃希氏菌中有3株携有毒力基因hlyA、STb、F17。致病性试验显示,在分离出的8株大肠埃希氏菌中4株为致病性大肠埃希氏菌,分离出的沙雷氏菌和产色葡萄球菌对小鼠均有致病力,可使部分小鼠死亡。药敏试验显示,分离出的致病性大肠埃希氏菌普遍对庆大霉素、环丙沙星、美罗培南敏感;黏质沙雷氏菌对庆大霉素、环丙沙星、美罗培南等5种药物敏感,产色葡萄球菌对庆大霉素等11种药物敏感。水质检验显示,该牛场牛的饮用水中细菌总数和大肠埃希氏菌数量均严重超出国家标准。研究结果对预防、治疗奶牛产后败血症都具有指导意义。

The assay was aimed to clarity the reason why the dairy cows become ill with the symptoms including fever,breathing difficulty,and blood in the milk,even part of them were dead for exhaustion.In this study,the samples from heart,liver,uterus and milk were collected.The disease was diagnose by 16srRNA sequence test,virulence gene test,pathogenicity test and drug sensitivity test.Besides,the water also be test by bacterial count.The result showed that the pathogens were Escherichia coli,Serritia marcescens and Staphylococcus chromogenes.The virulence gene tests showed that 3 out of 20 E.coli strains carry virulence genes hlyA,STb and F117.Four of the eight strains of E.coli are pathogenic E.coli.The Serritia marcescens and Staphylococcus chromogenes also can cause mouse death.The drug sensitivity test showed that E.coli we isolated is sensitive to gentamicin,ciprofloxacin,and meropenem;Serratia is sensitive to 5 drugs,such as gentamicin,ciprofloxacin,and meropenem,and Staphylococcus chromogenes is sensitive to 11 drugs,including gentamicin.Water quality inspection showed that both of the total number of bacteria and the number of E.coli in drinking water of the cattle seriously exceeded national standards.This study has guiding significance for the prevention and treatment of postpartum septicemia in dairy cows.