Epidemiology of bacteremic urinary tract infections in chronically hospitalized elderly men.

We sought to determine the contribution of pathogen-specific factors to the pathogenesis of invasive urinary tract infections in chronically institutionalized elderly men with symptomatic bacteriuria. We found that Escherichia coli was the most invasive pathogen, being found in 46% of the bacteremic as opposed to 25% of the nonbacteremic, rigorously defined urinary tract infections (p less than 0.01). The predominance of E. coli in bacteremic urinary tract infections was observed regardless of whether indwelling urinary drainage devices were used. The finding that E. coli accounted for a greater proportion of bacteremic than nonbacteremic urinary tract infections indicates that bacteremia arising from the geriatric urinary tract is not simply a consequence of mechanical factors, such as urinary tract obstruction. Thus, further investigations are warranted to assess the specific contribution of previously defined E. coli virulence factors to the pathogenesis of urinary tract infections in such patients.