Degradation of human fibronectin by strains of E. coli K12 carrying R factors from Klebsiella pneumoniae.

We studied the ability to degrade human fibronectin by strains of E. coli K12 carrying R factors from Klebsiella pneumoniae, previously shown to possess a caseinolytic activity. The preliminary data obtained showed that at least two of these R+ strains are able to degrade fibronectin to small peptides retaining the gelatin-binding site of the molecule. We also found indications of non-fibronectin gelatin-binding polypeptides secreted by the strains tested into the culture broth. The possible significance of this bacterial property as a factor of pathogenicity is discussed.