Blood Cultures Are Not Useful in the Evaluation of Children with Uncomplicated Superficial Skin and Soft Tissue Infections

Background: Blood cultures (BCs) are commonly performed on children admitted to hospital for skin and soft tissue infections (SSTIs). In recent years, this practice has been questioned in patients with uncomplicated SSTIs because of its low yield. At the same time, however, an increase in community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections has been described; its influence on rates of bacteremia in patients with SSTIs is unclear. The aims of the study were to describe the performance and the yield of BC in immunocompetent patients with uncomplicated SSTIs and to determine the prevalence of CA-MRSA as a causative agent in our area. Methods: Retrospective study: immunocompetent patients younger than 18 years evaluated in the emergency department and admitted for uncomplicated SSTIs (cellulitis, abscess, impetigo or erysipelas) from July 1, 2010 to June 31, 2014 were included. Patients referred from other hospitals who were receiving parenteral antibiotics and patients with complicated SSTIs (surgical or traumatic wound infection, need for surgical intervention and infected ulcers or burns) were excluded. Results: We included 445 cases: 348 (78.2%) cellulitis, 78 (17.5%) abscess and 19 (4.3%) impetigo. BCs were performed on 353 (79.3%) patients. Two (0.6%; 95% confidence interval: 0.2-2.0%) were positive and 10 (2.8%; 95% confidence interval: 1.5-5.1%) contaminated. The positive BCs grew S. aureus and Streptococcus pyogenes. Wound cultures were performed on 148 (33.3%) patients; 98 (66.2%) were positive. In 22 (22.4%) patients CA-MRSA grew, accounting for 14.9% of overall wound cultures. Conclusions: BCs are not useful in the management of immunocompetent patients admitted to the hospital with uncomplicated SSTIs. The prevalence of CA-MRSA is low in our area, but continuing careful surveillance is needed.