Epidemiology and Outcome of Klebsiella Species Bloodstream Infection: A Population-Based Study

OBJECTIVE: To determine Incidence rate, seasonal variation, and short- and long-term outcomes of Klebsiella species bloodstream infection (BSI) In a population-based setting. PATIENTS AND METHODS: We identified 127 unique patients In Olmsted County, Minnesota, from January 1, 1998, to December 31, 2007, who had Klebsiella spp BSI. Multivarlable Poisson regression was used to examine temporal change and seasonal variation in incidence rate, and Cox proportional hazards regression was used to determine predictors of mortality. RESULTS: The age-adjusted incidence rate of Klebsiella spp BSI per 100,000 person-years was 15.4 (95% confidence interval [CI], 11.6-19.2) in men and 9.4 (95% CI, 7.0-11.8) in women. There was no linear increase in incidence rate of Klebsiella spp BSI during the study period (P=.55). The incidence rate of Klebsiella spp BSI increased at quadratic rate with age (P=.005). No significant difference was noted in incidence rate of Klebsiella spp BSI during the warmest 4 months compared to the rest of the year (incidence rate ratio, 0.97; 95% CI, 0.66-1.38; P=.95). The overall 28-day and 1-year all-cause mortality rates of Klebsiella spp BSI were 14% (95% CI, 9%22%) and 35% (95% CI, 27%-44%), respectively. Respiratory source of BSI was associated with a higher 28-day mortality (hazard ratio, 4.90; 95% CI, 1.73-13.84; P=.003). CONCLUSION: The Incidence rate of Klebsiella spp BSI increased with age. There was no temporal change or seasonal variation in Incidence rate of Klebsiella spp BSI during the past decade. The 28-day all-cause mortality rate of Klebsiella spp BSI was relatively low; however, a respiratory source of BSI was associated with a poorer outcome.