2. Academic Validation
  3. Role of long polar fimbriae type 1 and 2 in pathogenesis of mammary pathogenic Escherichia coli

Role of long polar fimbriae type 1 and 2 in pathogenesis of mammary pathogenic Escherichia coli

  • J Dairy Sci. 2021 Jul;104(7):8243-8255. doi: 10.3168/jds.2021-20122.
Mingxu Zhou 1,  Yang Yang 2,  Miaomiao Wu 3,  Fang Ma 4,  Yue Xu 4,  Bihua Deng 4,  Jinqiu Zhang 4,  Guoqiang Zhu 5,  Yu Lu 6
Affiliations

Affiliations

  • 1 Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Nanjing 210014, China.
  • 2 Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China; College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China.
  • 3 College of Animal Science and Technology, Hunan Co-Innovation Center of Animal Production Safety, Hunan Agricultural University, Changsha 410128, China.
  • 4 Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
  • 5 Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China; College of Veterinary Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou 225009, China. Electronic address: [email protected].
  • 6 Institute of Veterinary Immunology & Engineering, National Research Center of Engineering and Technology for Veterinary Biologicals, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China; School of Pharmacy, Jiangsu University, Zhenjiang 212013, China. Electronic address: [email protected].
PMID: 33814154 DOI: 10.3168/jds.2021-20122
Abstract

Escherichia coli is a leading cause of bovine mastitis worldwide. The bacteria can rapidly grow in milk and elicit a strong lipopolysaccharide (LPS)/toll-like receptor-4 (TLR4)-dependent inflammatory response. Recently, the long polar fimbriae (LPF) were identified as a promising virulence factor candidate widely distributed in mammary pathogenic E. coli (MPEC) strains. Mammary pathogenic E. coli possess 2 lpf loci encoding LPF1 and LPF2, respectively. By deleting the major fimbrial subunit gene, lpfA, we found that both LPF1 and LPF2 contribute to MPEC adhesion, invasion, and biofilm formation in vitro. The lpf1A and lpf2A mutants showed reduced cytotoxicity in our in vitro cell Infection model. Furthermore, we observed that LPF2 induced a mild TLR4-independent proinflammatory response. The median lethal dose (LD50) of both ∆lpf2A and ∆lpf1A∆lpf2A mutants to BALB/c mice increased by 0.38 and 0.15 logs, respectively, whereas that of wild-type strain MPJS13 was 8.69 logs. In contrast, LPF1 deficiency significantly enhanced the LPS/TLR4-mediated inflammatory response in mammary epithelial cells, and the LD50 of the mutant decreased to 8.18 logs. In conclusion, our data suggested that LPF are important in MPEC colonization of mammary cells and may provide a benefit to Bacterial intracellular survival that induces persistent bovine mastitis.

Keywords

Escherichia coli; inflammatory response; long polar fimbriae; mastitis; pathogenesis.

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