Citrobacter spp. bloodstream infection primarily affects the elderly either hospitalized or closely associated with health care – a population-based observational study with comparisons between C. koseri and the C. freundii complex

Citrobacter BSI was primarily found in elderly patients, either hospitalized or in close contact with healthcare in other ways. C. koseri BSI was to a greater extent associated with urinary tract focus compared to patients with BSI due to C. freundii complex, which was associated with abdominal source of infection and polymicrobial BSI.