Epidemiology and outcome of nosocomial bloodstream infection in elderly critically ill patients: A comparison between middle-aged, old, and very old patients*

Abstract

Over the past 15 years, an increasing number of elderly patients were admitted to our ICU. The incidence of nosocomial bloodstream infection is lower among very old ICU patients when compared to middle-aged and old patients. Yet, the adverse impact of this infection is higher in very old patients.

Bloodstream infections in older patients

“…17,20,22 Acute kidney injury is reported to be more common in older than younger patients in some studies, 11,20,23 although not all. 13,22 CRP >D 8 mg/dl was as common in older patients as in younger patients in one study, however median CRP levels in the group of patients aged 65-74 y were significantly lower compared to younger patients. 22 The role of procalcitonin in the diagnosis of bacteremia in older patients is yet to be defined.…”

“…9,12 Others explained the significant increase in prevalence of BSIs in patients aged 65 y and older by the increase in hospitalization rates of older patients. 13 Older patients are at risk for health care associated or hospital acquired BSIs. In a recent large series evaluating community onset BSIs in patients aged 65 y and older, 37.5% of bacteremias were health care associated.…”

“…Vascular catheter was reported as the source of infection in 1-10%, with higher rates reported in studies including nosocomial BSI (20%) (3) or ICU patients (13-19%). 13 Endovascular source is reported in 1-6%. Unknown source and primary bacteremia rates are variable and depend on definitions of infection in the various studies.…”

“…In a study including only nosocomial BSIs requiring ICU hospitalization, Gram positive organisms (»50%) were more common than Gram negative organisms (»40%) with Staph coagulase negative being the most common isolate. 13 Older patients are at increased risk for colonization with Gram negative bacteria. Nursing home residency, hospitalization, respiratory disease and poor functional status are all risk factors for Gram-negative colonization.…”

“…14,20,33 In a large series from Finland, it was the most common pathogen in men aged 65 y and older with BSI acquired in both community and nosocomial setting. 9 In nosocomial BSIs, E. coli represents 10-20% of BSIs, 3,13 while Staphylococcus aureus and Staphylococci coagulase negative assume prominence. According to SENTRY study, S. aureus caused~30% of nosocomial BSI in patients 65 y and older.…”