基于不同ST型肺炎克雷伯菌感染的小鼠乳腺炎模型的差异分析  

Differential Analysis of Mastitis Model in Mice Infected with Klebsiella pneumoniae of Different ST Types

作　　者：任美奕 梁洪秀 李璨 冯鸣鹊 谢琴娜 宋德源 刘明超 高健[2] 程佳 REN Meiyi;LIANG Hongxiu;LI Can;FENG Mingque;XIE Qinna;SONG Deyuan;LIU Mingchao;GAO Jian;CHENG Jia(College of Veterinary Medicine,Hebei Agricultural University,Baoding 071001,China;College of Veterinary Medicine,China Agricultural University,Beijing 100193,China)

机构地区：[1]河北农业大学动物医学院,保定071001 [2]中国农业大学动物医学院,北京100193

出　　处：《中国畜牧兽医》2025年第1期422-431,共10页China Animal Husbandry & Veterinary Medicine

基　　金：河北省生物农业联合基金培育项目(C2023204074);河北省省属高等学校基本科研业务费研究项目(1081002240);河北农业大学引进人才科研专项(3118133);河北省现代农业产业技术体系第三期奶牛创新团队建设项目(HBCT2023180201)。

摘　　要：[目的]肺炎克雷伯菌感染是奶牛乳腺炎的常见病因,其诱导的临床型乳腺炎发病急、临床症状重,牛奶产量和质量降低,给奶牛场造成巨大的经济损失。本研究旨在探究奶牛乳腺炎源性不同序列型(sequence type, ST)肺炎克雷伯菌的毒力作用,筛选肺炎克雷伯菌发挥感染作用的潜在关键毒力基因。[方法]采用多位点序列分型(multi-locus sequence typing, MLST)分析山东、湖北2个大型奶牛场的129株临床乳腺炎源性肺炎克雷伯菌的ST型分布,并选择3种检出率较高的ST型肺炎克雷伯菌感染小鼠建立乳腺炎模型,探究小鼠乳腺的形态学损伤及炎性因子表达变化。通过分析肺炎克雷伯菌的感染特性与毒力基因分布,筛选与肺炎克雷伯菌感染相关的关键毒力基因。[结果]129株肺炎克雷伯菌共分为79种ST型,其中ST107占比最高,为19.37%;其次为ST2324(7.75%)和ST13(3.87%)。与ST107和ST13型相比,感染后24 h, ST2324型肺炎克雷伯菌诱导小鼠临床评分和乳腺载菌量均显著升高(P<0.05);乳腺内腺泡轮廓消失和大量炎性细胞浸润,乳腺中白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)和细胞色素C(Cyt C)mRNA表达量均显著升高(P<0.05)。毒力基因检测结果显示,3种不同ST型分离株共检测到74个毒力基因,其中ST2324型分离株中检出了ST13和ST107型分离株没有检出的毒力基因manB、pla和pilW。[结论]本研究从129株肺炎克雷伯菌中共检出79种ST型,其中ST2324、ST107和ST13检出率较高,ST2324型肺炎克雷伯菌对小鼠致病性最强,且携带的毒力基因manB、pla和pilW与肺炎克雷伯菌的高致病性密切相关。本研究结果为进一步解析肺炎克雷伯菌感染奶牛乳腺炎的机制提供了理论参考。[Objective]Klebsiella pneumoniae infection is a common cause of mastitis in dairy cows,which induces acute clinical mastitis with severe clinical symptoms,resulting in reduced milk production and quality,thereby causing significant economic losses to dairy farms.The purpose of this study was to explore the virulence effects of different sequence types(ST)of Klebsiella pneumoniae originating from cow mastitis,and screen for potential key virulence genes that contribute to the infectious role of Klebsiella pneumoniae.[Method]The multi-locus sequence typing(MLST)method was employed to analyze the distribution of ST among 129 strains of Klebsiella pneumoniae isolated from clinical mastitis cases in two large dairy farms located in Shandong and Hubei provinces.Subsequently,3 of the most prevalent ST of Klebsiella pneumoniae were selected to establish mastitis model in mice,and the morphological damage and expression changes of inflammatory factors in mammary glands of mice were investigated.The key virulence genes associated with Klebsiella pneumoniae infection were screened by analyzing the infection characteristics and virulence gene distribution of Klebsiella pneumoniae.[Result]129 strains of Klebsiella pneumoniae were categorized into 79 ST types,of which ST107 accounted for the highest proportion of 19.37%,followed by ST2324(7.75%)and ST13(3.87%).Compared with ST107 and ST13,ST2324 induced Klebsiella pneumoniae clinical score and mammary gland bacteria load were significantly increased 24 h after infection(P<0.05).The acinar contour disappeared and a large number of inflammatory cells infiltrated,and the mRNA expressions of interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α),and cytochrome C(Cyt C)were significantly increased(P<0.05).Virulence gene detection results showed that 74 virulence genes were detected in 3 different ST isolates,among which the virulence genes manB,pla and pilW were detected in ST2324 but not in ST13 and ST107.[Conclusion]In this study,a total of 79 ST types were detected from 129 st

关 键 词：奶牛乳腺炎 肺炎克雷伯菌 序列型(ST) 毒力基因 

分 类 号：S858.292[农业科学—临床兽医学]