Binding of fibronectin to Escherichia coli isolated from bovine mastitis from different geographical regions.

Seventy strains of Escherichia coli, isolated from bovine mastitis in Australia, Denmark, Norway and the U.S.A., were tested for their ability to bind fibronectin. Fifty-three strains (76%) interacted with iodinated fibronectin at a level exceeding 5% of the total radioactivity added. Binding of the amino-terminal (29 kD) fragment of fibronectin was tested for 15 strains, and 6 strains (40%) bound greater than 5%. Bacteria binding the 29 kD fragment at greater than or equal to 19% of the added protein, consistently showed "high" attachment to bovine skin fibroblasts. These cells were shown by immunofluorescence to produce extracellular matrix containing fibronectin. Strains binding lower amounts of fibronectin or 29 kD fragment adhered poorly to these fibroblasts.