Fever is a common complaint in the emergency room (ER). Blood cultures (BCs) are drawn to detect bacteremia which has substantial impact on treatment.
Objective: To characterize the clinical and laboratory features of children with positive BCs.
Children aged 3 months-18 years with positive BCs obtained during their febrile illness 2007-2017 at a hospital northern Israel were studied retrospectively. Patients with a central-line or known immunodeficiency were excluded.
34,066 BCs were drawn during 77,397 ER visits (44%) of which 909 cultures (2.6%) were positive. After excluding patients at risk for bacteremia, 671 positive cultures remained, 369 in males, 183<=1 year, 250 1-3 years, 238>3 years. 74.5% were from the ER. 8 patients were excluded due to incomplete medical records.
Of the remaining 663 positive cultures, 101(15.2%) revealed bacteremia, (0.3% of total samples) and the rest were deemed contaminants. The number needed to test for one non-contaminated BC was 338 (95% CI:278-412).
Age and gender were not associated with a higher prevalence of positive culture (P=0.18, P=0.1). Contaminants were coagulase negative Staphylococcus (51%), Streptococcus Viridans (13%) and Micrococcus species (6.3%). Rate was not influenced by age (p= 0.18). Respiratory symptoms were correlated with a higher contamination rate (P= 0.001).
Higher ANC and CRP were observed with true bacteremia compared to contaminated cultures;(P=0.05, P=0.001).
Conclusion: Given the low rate of positive BCs, careful clinical assessment is warranted in order to minimize false negatives. Improvements in approaches for drawing BCs are needed in order to reduce the high rate of contamination.
