Adherent and invasive Escherichia coli are associated with persistent bovine mastitis

• Published in: Veterinary microbiology Vol. 116; no. 4; pp. 270 - 282
• Main Authors: Dogan, Belgin, Klaessig, S., Rishniw, M., Almeida, R.A., Oliver, S.P., Simpson, K., Schukken, Y.H.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 10-09-2006; Elsevier Science
• Subjects: Adhesion; Analysis of Variance; animal physiology; Animals; Bacterial Adhesion; Bacteriology; biochemical pathways; Biological and medical sciences; bovine mastitis; Cattle; cell invasion; Cells, Cultured; Chronic; chronic diseases; Colchicine - pharmacology; Cytochalasin D - pharmacology; dairy cattle; Enzyme Inhibitors - pharmacology; epithelial cells; Epithelial Cells - microbiology; Escherichia coli; Escherichia coli - classification; Escherichia coli - pathogenicity; Escherichia coli - physiology; Escherichia coli Infections - microbiology; Escherichia coli Infections - veterinary; Escherichia infections; Female; Fundamental and applied biological sciences. Psychology; Genistein - pharmacology; Genotype; immune response; immunocompetence; In Situ Hybridization, Fluorescence - veterinary; in vitro culture; in vitro studies; Invasion; MAC-T cells; Mammary Glands, Animal - microbiology; Mastitis; Mastitis, Bovine - microbiology; Mastitis, Bovine - pathology; Microbiology; Miscellaneous; Pathogenicity; Phylogeny; Serotyping; strain differences; strains; Survival; udders; Virulence; Pathogenicity; MAC-T cells; Chronic; Mastitis; Escherichia coli; Adhesion; Survival; Invasion; Bovine; Microbiology; Mammary gland diseases; Vertebrata; Mammalia; T-Lymphocyte; Bacteria; Artiodactyla; Veterinary; Ungulata; Enterobacteriaceae
• ISSN: 0378-1135; 1873-2542
• DOI: 10.1016/j.vetmic.2006.04.023

Bovine mastitis caused by
Escherichia coli has traditionally been viewed as a transient infection. However,
E. coli can also cause clonal persistent intramammary infection (IMI) in dairy cows. In this study, we explored the possibility that
E. coli strains associated with persistent IMI are better able to adhere to, invade, survive and replicate in cultured mammary epithelial cells (MAC-T) than transient strains, and examined their serotype, overall genotype, phylogenetic group, and the presence of known virulence genes.
Both transient and persistent
E. coli strains adhered to MAC-T cells, but persistent strains invaded MAC-T cells 2.6–63.5 times more than transient strains. Blocking the adhesin/invasin FimH with mannose diminished but did not eliminate adhesion and invasion of any strain. Cytoskeletal and protein kinase inhibitors cytochalasin D, colchicine, genistein and wortmannin dramatically reduced invasion of MAC-T cells by both strains. All of the persistent strains, but only one transient strain, were able to survive and replicate intracellularly in MAC-T cells over 48
h. Transient and persistent strains displayed heterogeneous serotypes and overall genotypes, but similar phylogeny (group A), and lacked virulence genes of invasive
E. coli.
We have found that
E. coli strains associated with persistent IMI are better able to invade and replicate within cultured mammary epithelial cells than transient strains. The invasion process involves the host cytoskeleton and signaling cascades and is not FimH dependent. Our findings suggest that the invasion of mammary epithelial cells and intracellular survival play an important role in the pathogenesis of persistent
E. coli mastitis.