Continuing the search for bacterial urovirulence factors.

Bacteria that commonly cause infections of the normal urinary tract (eg Escherichia coli, Proteus mirabilis and Staphylococcus saprophyticus) do so because they possess specific urovirulence factors. Adhesions of various types (often fimbriae) seem to be the most important of these. In E. coli several other factors have been recognized, and sub-sets of defined uropathogenic clones exist. On the other hand, urovirulence determinants are less easy to distinguish in species such as S. epidermidis and Klebsiella pneumoniae, that rarely cause such infections, or are pathogenic only in the presence of some abnormality or deficiency in host defences.