核农学报2025，Vol.39Issue(11)：2407-2417,中插5,12.DOI:10.11869/j.issn.1000-8551.2025.11.2407
奶牛乳源海氏肠球菌分离鉴定及致病性分析
Isolation,Identification and Pathogenicity Analysis of Enterococcus hirae from Dairy Cow Milk
摘要
Abstract
In recent years,the prevalence of Enterococcus hirae in subclinical mastitis cases of dairy cows has been increasing gradually.By using bacteriological,morphological and molecular-biological methods,a strain named EH-GY8 was successfully isolated from the positive milk samples of dairy cows with subclinical mastitis.The bacterium was characterized through investigating its growth characteristics,drug resistance,whole-genome sequencing and mouse-challenge modeling.The results showed that EH-GY8 was a G+coccus with γ-hemolytic activity.The logarithmic growth phase of EH-GY8 lasted from 2 to 7 hours,with the optimal growth conditions at 30℃and pH=7,and a genome size of 2 747 743 bp.Notably,the bacterium exhibited resistance to vancomycin and levofloxacin.In animal experiments,significant increases in blood-routine indices of the challenged group were observed(P<0.05).A large number of bacteria were present in the breast tissue,with severe disruption of the mammary gland acini through epithelial-cell detachment and glandular disorganization.Pronounced interstitial congestion occurred alongside extensive infiltration of inflammatory cells.The expression levels of related inflammatory factors(IL-1β,IL-6,and TNF-α)increased significantly(P<0.05),presenting a trend of first increasing and then decreasing.Specifically,disease onset on the third day after the challenge.This study comprehensively discusses the pathogenesis of Enterococcus hirae,providing significant insights and a theoretical basis for the prevention and control of subclinical mastitis and related diseases in dairy cows.关键词
隐性乳房炎/海氏肠球菌/分离鉴定/耐药性和致病性分析Key words
subclinical mastitis/Enterococcus hirae/isolation and identification/analysis of drug resistance and pathogenicity引用本文复制引用
常剑英,潘阳阳,王萌,杨晓晴,李天昊,马鑫,张小坤,杨娟..奶牛乳源海氏肠球菌分离鉴定及致病性分析[J].核农学报,2025,39(11):2407-2417,中插5,12.基金项目
国家自然科学基金地区项目(32460905),甘肃省重点研发计划-农业领域(24YFNA015) （32460905）
