Utility of blood cultures in febrile children with UTI

The objective of the study was to define the prevalence of bacteremia in febrile children <18 years of age diagnosed to have acute urinary tract infection (UTI). Retrospective chart review of patients diagnosed to have a UTI in the emergency department (ED) of an urban, tertiary care children's hospital was conducted Seven hundred forty-four children were discharged or admitted from the ED with a diagnosis of UTI during the study period. Thirty-six (4.8%) patient records were unavailable for review; 343 met inclusion criteria. Two hundred forty-nine patients (72.8%) had a history of fever. Blood cultures were performed on 183 (53.4%) patients. Of febrile patients, 178 (71.5%) had a blood culture performed. Seventeen of 183 (9.3%) blood cultures were positive. All (17/178, 9.5%) positive blood cultures were obtained from febrile patients. Seven of the positive blood cultures were considered to be contaminated. The prevalence of true bacteremia in febrile patients was 5.6%. All 10 patients with a true pathogen recovered from the blood culture had the same organism in their urine culture. The prevalence of bacteremia in patients younger than 2 months was 22.7% and in patients between the ages of 2 months and 36 months, 3.0%. Patients with a positive blood culture were more likely to be younger, to have been hospitalized and to have had a longer duration of hospitalization. No difference was found between patients with a positive blood culture and those without in regards to the number of days of illness before presentation, time to defervescence and mean white blood cell count. Bacteremia in children with UTI is most common in very early infancy. Children with UTI between the ages of 2 months and 12 years appear to have a low risk of bacteremia. Children who are bacteremic are likely to have identical organisms with identical antimicrobial sensitivities in both the urine and blood culture.