Evaluation of the accuracy of procalcitonin for differentiating between Gram-negative and Gram-positive bacterial sepsis in pediatric burn patients

Background: Burn injuries disrupt skin integrity, increasing the risk of sepsis, a leading cause of morbidity and mortality in burn patients. Rapid differentiation between Gram-negative and Gram-positive bacterial sepsis is critical for timely and effective antibiotic therapy. Serum procalcitonin (PCT) has emerged as a potential biomarker for sepsis differentiation. Objective: This study aimed to evaluate the diagnostic accuracy of serum PCT in distinguishing between Gram-negative and Gram-positive bacterial sepsis in pediatric burn patients. Methods: A cross-sectional study was conducted on 117 pediatric burn patients with positive blood cultures and clinical diagnosis of sepsis based on American Burn Association criteria. Serum PCT levels were quantified and compared with blood culture results. Diagnostic performance was assessed using receiver operating characteristic (ROC) curves to determine optimal PCT cut-off values. Results: Gram-negative bacteria were identified in 60.2% of cases, while Gram-positive bacteria were detected in 39.8%. Serum PCT levels were significantly higher in Gram-negative sepsis cases (mean: 14.58 ng/mL) compared to Gram-positive sepsis cases (mean: 4.62 ng/mL, p < 0.001). An optimal PCT cut-off value of 3.15 ng/mL demonstrated 84.3% sensitivity and 57.4% specificity for detecting Gram-negative sepsis. Patients with Gram-negative sepsis experienced longer hospital stays, elevated inflammatory markers, higher organ dysfunction, and increased mortality rates (31% vs. 2%, p < 0.001) than Gram-positive sepsis. Conclusion: Serum PCT provides moderate sensitivity but low specificity in differentiating Gram-negative from Gram-positive bacterial sepsis in pediatric burn patients. PCT may serve as a valuable adjunct to clinical and laboratory indicators. Larger multicenter studies are warranted to validate these findings and refine diagnostic algorithms for sepsis management.