The predisposing factors of coagulase negative staphylococcal bacteraemia in neonatal intensive care unit

Coagulase negative staphylococci are the commonest blood culture isolate from infants on neonatal intensive care units. The differentiation of contaminants from isolates representing true infection remains a significant clinical problem. Data from two neonatal intensive care units were collected prospectively in order to find those parameters, which best correlated with actual sepsis. Each case was assessed using clinical parameters to categorise infants into infection and contaminant groups. Logistic regression was then performed to find significant correlates. Three correlates were found, namely the presence of a long line (P = 0.001), abnormal white cell count (P = 0.037) and abnormal white cell morphology (P = 0.027). Abnormal white cell morphology was assessed by two experienced hematologists. More than half the isolates were probable contaminants and true infection may occur in the absence of a long line in this patient group.