内蒙古地区奶牛源沙门氏菌的分离、鉴定及其对小鼠的致病性研究

Study on Identification and Pathogenicity of Salmonella Isolates from Dairy Cattles in Inner Mongolia

本研究旨在通过对内蒙古地区奶牛源沙门氏菌的分离、血清学鉴定及其对小鼠的致病性研究,探明本地区奶牛源沙门氏菌的血清型分布及其对小鼠的致病力强度,为兽医临床防制由沙门氏菌引起的奶牛感染性疾病提供依据。采用SC增菌液和SS琼脂从兽医临床采集的奶牛乳房炎和奶牛子宫内膜炎病料中分离沙门氏菌;对分离到的疑似菌落进行涂片染色镜检和生化鉴定;采用A^F群O抗原多价诊断血清及单价诊断血清对疑似沙门氏菌进行血清型鉴定;采用腹腔注射感染小鼠,观察部分菌株对小鼠的致病和致死情况,并进行病理学检查。结果显示,从460份病料中共分离、鉴定出沙门氏菌38株,分离率为8.3%;38株分离菌均分布于A^F群内,分属8个群、14种血清型,其中鼠伤寒沙门氏菌分离率最高(39.5%);选择的5株沙门氏菌攻毒后均可引起小鼠发生死亡,死亡率在50%~80%之间;在感染小鼠的心脏、肝脏均回收到了攻毒菌,且发病小鼠的心脏、肝脏和肾脏出现坏死灶,肺脏有细菌性栓子。结果表明,内蒙古地区奶牛源沙门氏菌血清型分布较复杂,对小鼠有较强的致病性,且不同血清型菌株间的毒力存在差异。

The objective of the present study was to observe the distribution of the serotypes and pathogenicity to mice of Salmonella isolated from dairy cattles with mastitis or endometritis. Salmonella strains were isolated by selective medium. The serotype of the isolates were determined by A to F polyvalent and O and H monovalent diagnostic serum agglutination test;Mice infection model was induced by intraperitoneal injecting of the Salmonella isolates. The morbidity and mortality of the mice were observed. Tissue lesions were also observed by using tissue sectioning. A total of 38 of Salmonella strains were isolated and identified from 460 samples of bovine mastitis or endometritis, the isolating rate of pathogenic Salmonella was 8.3%. 38 strains all belonged to A to F group, and 8 groups and 14 serotypes were observed. S. typhimuriam （39.5%）was the most commonly isolated Salmonella. Mortality of five selected strains ranged from 50% to 80% respectively. Meanwhile, Salmonella strains were recovered from each experimental mouse＇s hearts and livers. There were necrosis in heart, liver and kidney of mice. Bacterial embolus was observed in lung of infected mice. Salmonella isolated from dairy cattles had complex serotypes and were strongly pathogentic to mice, but there were differences in pathogenicity of different Salmonella isolates.