Clinical question: What is the yield of blood cultures performed on pediatric patients admitted for uncomplicated and complicated skin and soft tissue infections (SSTIs and cSSTIs)?
Background: SSTIs are a common cause of pediatric ED visits and hospitalizations. Current Infectious Diseases Society of America (IDSA) guidelines include obtaining a blood culture for patients who show signs of systemic toxicity. Blood cultures are performed frequently in all pediatric patients hospitalized for SSTI and cSSTI. Little recent data exists about the rate of bacteremia in pediatric SSTI since the widespread emergence of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) and adoption of routine vaccination for Haemophilus influenzae type B (HiB) and varicella.
Study design: Single-center, retrospective case series.
Setting: University-affiliated pediatric hospital at a tertiary medical center.
Synopsis: Researchers used the hospital’s electronic medical record system to search for patients between the ages of 0 and 18 years hospitalized for SSTI/cSSTI. Initial screening of the data utilized ICD-9-CM codes for cellulitis and abscess (682.X), with subsequent review by investigators to exclude miscoded cases, immunocompromised patients, hospital-acquired infection, and incidentally noted SSTI during admissions for other problems. SSTIs were classified as being complicated in the cases of surgical or traumatic wound infection, need for surgical intervention, and infected ulcers or burns. Routine incision and drainage did not constitute surgical intervention.
Of the 580 patients remaining, 482 were classified as having SSTI, of which 455 underwent testing with blood cultures. None of the blood cultures led to pathogenic bacterial growth after 120 hours of incubation; three grew S. epidermidis. Of the 98 patients classified as having cSSTI, 80 underwent blood culture testing, of which 10 (12.5%) were positive.
Pathogens identified in positive blood cultures included MRSA (6), methicillin-sensitive S. aureus (3), and S. pneumococcus (1). Length of stay was significantly longer for patients with SSTI who underwent blood culture testing (3.24 days) compared to those who did not (2.33 days).
Bottom line: Obtaining blood cultures in a child hospitalized with uncomplicated SSTI is highly unlikely to be helpful in obtaining a bacteriologic diagnosis. Even worse, it will likely increase the length of stay for these patients.
Citation: Malone JR, Durica SR, Thompson DM, Bogie A, Naifeh M. Blood cultures in the evaluation of uncomplicated skin and soft tissue infections. Pediatrics. 2013;132:454-459.
Reviewed by Pediatric Editor Weijen Chang, MD, SFHM, FAAP, associate clinical professor of medicine and pediatrics at the University of California at San Diego School of Medicine, and a hospitalist at both UCSD Medical Center and Rady Children’s Hospital.