Blood Cultures in the Evaluation of Children With Cellulitis

Objective. To evaluate the yield of blood cultures obtained from immunocompetent children admitted for cellulitis in the post-Haemophilus influenzae type b (Hib) vaccine era and to determine whether these cultures are cost-effective. Design. Retrospective case series. Setting. Urban pediatric emergency department. Study Population. Patients 2 days to 22 years of age admitted with cellulitis from 1994 through 1995. Measurements and Results. Of 381 patients identified, 266 (70%) had blood cultures and 243 of these children were enrolled. Data recorded include demographics, immunization status, initial clinical appearance, antibiotic pretreatment, preexisting illness, location and precipitating cause of cellulitis, white blood cell count, and bandto-neutrophil ratio (BNR). Blood cultures were categorized as positive, negative, or contaminant. Five cultures (2%) were positive, and 13 (5.4%) were contaminants. The positive blood cultures grew streptococcus and staphylococcus organisms, and none of the children were bacteremic with H influenzae. All patients with group A b-hemolytic streptococcus had active varicella. The mean age was lower (26 vs 75 months) in those with a positive blood culture, and mean BNR was higher (0.32 vs 0.07). Patient management did not change for bacteremic patients with uncomplicated cellulitis. All repeat cultures were negative. The cumulative charge for all blood cultures was $50 986. Conclusions. Blood cultures are not cost-effective and are more frequently contaminated than positive in the evaluation of a patient with uncomplicated cellulitis. Since introduction of the H influenzae type b vaccine, the most common organisms are streptococci. Using a BNR 5 0.20 as a threshold for sending blood cultures, we would have missed one positive culture, but would have avoided blood cultures in 213 patients (88%) with an estimated savings of $42 850. Pediatrics 1998;101(3). URL: http://www.pediatrics.org/cgi/content/full/101/3/e4; cellulitis, bacteremia, health care costs. ABBREVIATIONS. Hib, Haemophilus influenzae type b; ED, emergency department; WBC, white blood cell; BNR, band-to-neutrophil ratio; GABHS, group A b-hemolytic streptococcus; CI, confidence interval. Cellulitis is a common soft-tissue infection in pediatric patients. Children are prone to develop cellulitis because they frequently sustain minor traumatic injuries such as insect or animal bites, lacerations, and abrasions. Blood cultures are commonly performed on children admitted for cellulitis, despite previous literature suggesting a low yield except in cases of Haemophilus influenzae.1–3 Blood cultures have been advocated because of the high rate of bacteremia with H influenzae,1 but the prevalence of this pathogen has dramatically decreased since the introduction of the H influenzae type b (Hib) vaccine in 1985.2 The purpose of this study was to determine the yield of blood cultures obtained from children admitted for cellulitis in the post-Hib vaccine era. Our hypothesis was that blood cultures are not cost-effective in the management of immunocompetent patients admitted for cellulitis. A secondary aim of the study was to investigate clinical factors associated with positive blood cultures.