- Klebsiella spp. have emerged in recent years as a major cause of gram-negative bacteremia in infants and children. We therefore aimed to document the epidemiology, antibiotic susceptibility pattern and outcome of both community-acquired and nosocomial Klebsiella spp. bacteremias in children. From 1988-1997, 177 episodes of Klebsiella bacteremia, representing 15% of all gram-negative bacteremias, occurred at the Soroka Medical Center in 166 children aged 0-14 years. The overall incidence of Klebsiella bacteremia in southern Israel during the study period was 0.13/1,000, with an increase from 0.1 to 0.2/1,000 children from 1988-1992 to 1993-1997 (p = 0.02). 113 and 64 episodes were recorded in Bedouin Arabs and Jewish children, respectively. The incidence of Klebsiella bacteremia was significantly higher in Bedouins compared to Jewish children (p < 0.001). The incidence of Klebsiella bacteremia increased significantly among Jewish children from 1993-1997 compared to 1988-1992. The incidence of Klebsiella bacteremia was 2/1,000 admissions, with an increase from 1.8 to 2.2/1,000 from 1993-1997 compared to 1988-1992. The incidence of Klebsiella bacteremia was significantly higher among hospitalized Bedouin children compared to Jewish children (3.1 vs 1.4/1,000 admissions, p < 0.001). There were 48 (27%), 24 (14%) and 98 (55%) Klebsiella bacteremia episodes at the pediatric departments, pediatric intensive care unit (PICU) and neonatal intensive care unit (NICU), respectively. 76% of Klebsiella bacteremia episodes were nosocomial; 66% occurred at NICU. 71% and 90% of Klebsiella bacteremia episodes occurring at NICU and PICU, respectively, were nosocomial. The overall incidence of nosocomial infections was 1.5/1,000 admissions, with an increase from 1.2 to 1.8/1,000 from 1993-1997 compared to 1988-1992 (p = 0.03). The resistance rates of Klebsiella spp. to piperacillin, ceftriaxone, ceftazidime and gentamicin were 34%, 17%, 17% and 14%, respectively. A significant increase in the resistance rates to ceftriaxone and ceftazidime was observed from 1993-1997 compared to 1988-92 (21.9% vs 7.8%, p = 0.05 and 21.9% vs 5%, p = 0.03). A significant increase in resistance to ceftriaxone was recorded at PICU and NICU (from 12% and 0%, respectively, from 1988-1992, to 61% and 16%, respectively, from 1993-1997, p = 0.02). Overall mortality rate of Klebsiella bacteremia was 13% (21/167 cases, 12 and eight at PICU and NICU, respectively). An increase in Klebsiella bacteremia was recorded in southern Israel during the 10 years of the study. A marked increase in the rate of nosocomial Klebsiella bacteremia occurred at all departments. Resistance to third-generation cephalosporins emerged frequently at PICU and NICU during the last period of the survey.