Values of C-reactive protein, procalcitonin, and Staphylococcus-specific PCR in neonatal late-onset sepsis

AIM: To evaluate the predictive value of relevant clinical and laboratory parameters (complete blood count (CBC), C-reactive protein (CRP), procalcitonin (PCT) and Staphylococcus-specific polymerase chain reaction (PCR)) in neonates with suspected late-onset sepsis (LOS). METHODS: NICU neonates were prospectively followed for septic events. One hundred and eleven neonates developed 148 suspected septic events beyond 3 d of age. We recorded the clinical signs and laboratory abnormalities at onset of sepsis, serum CRP and PCT, Staphylococcus-specific PCR, microbiological data, and empiric antimicrobial therapy. RESULTS: Variables significantly associated with subsequently confirmed LOS included hypotension (relative risk (RR) = 5.6, 95% CI 3.29-9.53), mechanical ventilation (RR = 2.46, 95% CI 1.24-4.86), immature/total neutrophil ratio (I/T) > 0.2 (RR = 5.13, 95% CI 2.54-10.31), CRP > 1.0 mg/dl (RR = 2.85, 95% CI 1.32-6.15), and small-for-gestational-age (SGA) status (RR = 2.13, 95% CI 1.03-4.38). PCT was not significantly associated with LOS. For detection of staphylococcal bacteremia, Staphylococcus-specific PCR showed: sensitivity 57.1%, specificity 94.7%, positive predictive value 53.3%, and negative predictive value 95.4%. CONCLUSION: Hypotension, mechanical ventilation, I/T > 0.2, CRP > 1.0 mg/dl, and SGA status at onset of sepsis are significant predictors of proven neonatal LOS. Staphylococcus-specific PCR might be of value in ruling out staphylococcal sepsis.