A comparison of two versus one blood culture in the diagnosis and treatment of coagulase-negative staphylococcus in the neonatal intensive care unit

Objectives: This study compares two versus one blood culture in the diagnosis and treatment of coagulase-negative staphylococcus (CONS) in babies with suspected sepsis. Study Design: The study was performe at British Columbia's Children's Hospital Neonatal Intensive Care Unit between March 1999 to March 2000. One hundred pairs of cultures were drawn from two percutaneous sites from babies more than 48 hours old at the time of a sepsis screen. CONS cultured from both sites was regarded as evidence of infection. Positive culture from only one of the two sites was regarded as contaminant. The difference in rates of diagnosed CONS infection and reduction in antibiotic usage when using two versus one blood culture was calculated. Results: In 5% of babies, cultures from a second site did not substantiate the diagnosis of CONS when compared to the result from a single culture. The resultant reduction in antibiotic use was 8.2%. Conclusions: Two blood cultures reduce the number of children diagnosed with CONS infection and reduce antibiotic usage.