中国畜牧兽医 ›› 2026, Vol. 53 ›› Issue (2): 903-915.doi: 10.16431/j.cnki.1671-7236.2026.02.035

• 人兽共患病 • 上一篇    下一篇

奶牛源肺炎克雷伯菌和溶血性曼氏杆菌的分离鉴定与致病性分析

张随1,2(), 程纯结1,3(), 杨纯1,4, 陈梦娇1,4, 程晶1, 周林宜1, 李永清1, 王小莺2(), 刘文晓1,5()   

  1. 1.北京市农林科学院畜牧兽医研究所,北京 100097
    2.新疆农业大学动物医学学院,乌鲁木齐 830052
    3.江西农业大学动物科学技术学院,南昌 330000
    4.北京农学院动物科技学院,北京 102206
    5.英国帕布莱特研究所,沃金 GU240 NB
  • 修回日期:2025-05-13 出版日期:2026-02-20 发布日期:2026-01-27
  • 通讯作者: 王小莺,刘文晓 E-mail:2324212625@qq.com;ccj20200202@163.com;wangxiaoying6969@126.com;lwx232210809@163.com
  • 作者简介:张随,E-mail: 2324212625@qq.com
    程纯结,E-mail:ccj20200202@163.com
    第一联系人:(张随、程纯结并列第一作者)
  • 基金资助:
    北京市自然科学基金面上项目(6232012);国家自然科学基金面上项目(32172818);家畜产业技术体系北京市创新团队项目(BAIC06-2025);北京市乡村振兴农业科技(NY2502190125)

Isolation, Identification and Pathogenicity Analysis of Dairy Cow-derived Klebsiella pneumoniae and Mannheimia haemolytica

ZHANG Sui1,2(), CHENG Chunjie1,3(), YANG Chun1,4, CHEN Mengjiao1,4, CHENG Jing1, ZHOU Linyi1, LI Yongqing1, WANG Xiaoying2(), LIU Wenxiao1,5()   

  1. 1.Institute of Animal Husbandry and Veterinary Medicine,Beijing Academy of Agricultural and Forestry Sciences,Beijing 100097,China
    2.College of Veterinary Medicine,Xinjiang Agricultural University,Urumqi 830052,China
    3.College of Animal Science and Technology,Jiangxi Agricultural University,Nanchang 330000,China
    4.College of Animal Science and Technology,Beijing University of Agriculture,Beijing 102206,China
    5.Pirbright Institute,Woking GU240NB,United Kingdom
  • Revised:2025-05-13 Online:2026-02-20 Published:2026-01-27
  • Contact: WANG Xiaoying, LIU Wenxiao E-mail:2324212625@qq.com;ccj20200202@163.com;wangxiaoying6969@126.com;lwx232210809@163.com

摘要:

目的 鉴定引起奶牛死亡的原因,为多病原混合感染导致奶牛疾病的防治提供参考。 方法 采用平板划线法分离培养死亡奶牛乳样和血样中的病原菌,经细菌分离培养、革兰染色、16S rRNA序列分析、毒力基因鉴定等对分离株进行种属鉴定,利用纸片扩散法测定其对抗菌药的敏感性,通过动物试验进行分离株的致病性评价。 结果 乳样中细菌分离株在麦康凯培养基上呈湿润粉红色菌落的革兰阴性短杆菌。16S rRNA序列分析结果显示,分离菌与GenBank中克雷伯菌属代表菌株的序列相似性>99%,与肺炎克雷伯菌标准株ATCC 13883聚于同一分支,鉴定为肺炎克雷伯菌,将其命名为BJ-B004。毒力基因检测结果表明,该分离株含有7种毒力基因,包括fimHugewabGureAentBmrkDycf。药敏试验结果表明,其对链霉素、青霉素、阿莫西林、氨苄西林、复方新诺明耐药,对恩诺沙星、多西环素、氟苯尼考、四环素、大观霉素、头孢哌酮等抗菌药敏感。在该死亡奶牛的血样中分离出1株具有溶血特性的革兰阴性、两端钝圆的小杆菌,多呈单个或成对排列,瑞氏-吉姆萨复合染色呈两级浓染。16S rRNA序列分析结果显示,其与曼氏杆菌菌株序列相似性>98%,与牛源曼氏杆菌菌株ZY190616聚于同一分支,鉴定为溶血性曼氏杆菌,将其命名为BJ-B007。药敏试验结果表明,其对除庆大霉素外的抗菌药均不耐药。将肺炎克雷伯菌、溶血性曼氏杆菌以及混合菌液以3×107 CFU的剂量分别感染5只BALB/c小鼠,同时设PBS空白对照组(5只)结果显示,所有攻毒组小鼠均出现发病症状。48 h内混合感染组小鼠全部死亡,溶血性曼氏杆菌组死亡4只,肺炎克雷伯菌组死亡1只。病理学检查显示,溶血性曼氏杆菌引起肝脏、脾脏、肺脏、肾脏等多器官严重充血、出血及坏死病变。 结论 本研究从死亡奶牛的病料中分离到1株具有多重耐药性的肺炎克雷伯菌及1株具有高致病性的溶血性曼氏杆菌,该奶牛死亡原因为肺炎克雷伯菌感染引起乳房炎,继发条件致病菌溶血性曼氏杆菌感染引起菌血症,本研究结果为奶牛乳房炎和呼吸道综合征的联合诊断与综合防控提供科学依据。

关键词: 奶牛; 肺炎克雷伯菌; 溶血性曼氏杆菌; 分离鉴定; 致病性

Abstract:

Objective This study was conducted to identify the pathogens responsible for bovine mortality, aiming to provide a scientific reference for the prevention and control of diseases caused by co-infections with multiple pathogens in dairy cow. Method In this study, pathogenic bacteria were isolated and cultured from milk and blood samples of dead dairy cow using the plate streaking method. The isolates were subjected to species identification through Gram staining, 16S rRNA sequencing analysis, and virulence gene characterization. Antimicrobial susceptibility profiles were determined by the disk diffusion method, while pathogenicity was evaluated via animal challenge experiments. Result The bacterial isolate in the milk sample presented moist pink colonies of Gram-negative short bacilli on the McConkey medium. The results of 16S rRNA sequence analysis showed that the sequence similarity of the isolated bacteria to the representative strain of Klebsiella in GenBank was >99%, and it was clustered in the same branch as the standard strain of Klebsiella pneumoniaeK. pneumoniae) ATCC 13883. It was identified as K. pneumoniae and named BJ-B004. The results of virulence gene testing indicated that the isolate contained seven virulence genes, including fimHugewabGureAentBmrkD and ycf. The results of the drug sensitivity test showed that it was resistant to streptomycin, penicillin, amoxicillin, ampicillin, and cotrimoxazole, but was sensitive to antimicrobials such as enrofloxacin, doxycycline, florfenicol, tetracycline, spectinomycin, and cefoperazone. A small Gram-negative bacillus with hemolytic properties and rounded ends was isolated from the blood sample of the dead dairy cow. It was mostly arranged singly or in pairs and showed two-level concentrated staining by Wright-Giemsa staining. The results of 16S rRNA sequence analysis showed that its sequence similarity with the Mannheimia strain was >98%, and it was clustered in the same branch as the Mannheimia strain ZY190616 of bovine origin. It was identified as Mannheimia hemolyticusM. hemolyticusand named BJ-B007. The results of the drug sensitivity test indicated that it was not resistant to any antibacterial drugs except gentamicin. BALB/c mice were respectively infected with K. pneumoniaeM. hemolyticus and the mixed bacterial solution at dose of 3×107 CFU, with a PBS blank control group (n=5 per group), and the results showed that all the mice in the challenge group presented symptoms of the disease. All died within 48 h in mixed infection group, 4 died in M. hemolyticus group and 1 died in K.pneumoniae group. Pathological examination revealed that M. hemolyticus caused severe congestion, hemorrhage and necrotic lesions in multiple organs such as the liver, spleen, lung and kidney. Conclusion This study successfully isolated a multidrug-resistant K. pneumoniae strain and a highly pathogenic M. haemolytica strain from pathological samples of a dead dairy cow. The mortality was determined to be primarily caused by K. pneumoniae-induced mastitis, followed by secondary bacteremia due to opportunistic infection with M. haemolytica. The results provided a scientific foundation for the integrated diagnostic strategies and comprehensive prevention protocols targeting bovine mastitis-respiratory syndrome co-infections.

Key words: dairy cow; Klebsiella pneumoniae; Mannheimia haemolytica; isolation and identification; pathogenicity

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