Occurrence of P-fimbriated Escherichia coli in patients with bacteremia.

The case history of 88 patients with blood cultures positive for Escherichia coli and evidence of systemic disease was reviewed, and the Escherichia coli blood isolates tested for P-fimbriation. Fifty-five strains (63%) were P-fimbriated. Patients with a positive urine culture had a higher incidence of P-fimbriated Escherichia coli strains (53/75, 71%) than patients with a negative urine culture (2/13, 15%). Patients with no predisposing factors, such as instrumentation of the urinary tract or a chronic disease, had a significantly higher frequency of P-fimbriated strains (31/36, 86%) compared to patients without such underlying factors (p less than 0.01). There was no significant difference in clinical parameters or in frequency of P-fimbriated strains between patients with one positive blood culture and those with two or more positive cultures. The high incidence of P-fimbriated Escherichia coli strains in these patients is thought to depend on the ability of such bacteria to cause acute pyelonephritis, which in many cases precedes Escherichia coli bacteremia.