Investigation of the effect of K antigen in Escherichia coli urinary tract infections by use of a mouse model.

Urinary infection could be produced in mice by the inoculation of Escherichia coli into the bladder, provided that sutures had first been inserted into the bladder wall to act as foreign bodies. While the bladder was almost always infected, thekidneys were involved less often. The frequency of kidney infection was directly proportional to the K antigen of the infecting strain of E. coli. The significance of K antigens in relation to host defence mechanisms and tissue invasion is discussed.