A Study on the Bacteriological Spectrum and Diagnostic Utility of Acute Phase Markers in Neonatal Septicaemia

Background: Neonatal sepsis remains a major cause of morbidity and mortality in developing countries and requires timely diagnosis and appropriate antimicrobial therapy. Objectives: To determine the bacteriological spectrum and antimicrobial-resistance pattern of neonatal sepsis and to assess the diagnostic utility of C-reactive protein (CRP) and Procalcitonin (PCT). Methods: A hospital-based cross-sectional observational study was conducted among 110 neonates with suspected sepsis admitted to the NICU and SNCU of Bankura Sammilani Medical College & Hospital (March 2024–August 2025). Blood cultures were processed using the BACT/ALERT 3D system, isolates were identified by the Vitek 2 Compact System, and antimicrobial susceptibility testing was performed as per CLSI 2023 guidelines. Serum C-reactive protein (CRP) and procalcitonin (PCT) levels were measured by immunoturbidimetric and ELFA methods, respectively. Diagnostic performance was assessed using ROC curve analysis. Results: Of 110 neonates evaluated, 33 (30.0%) were culture-positive. Late-onset sepsis accounted for the majority of cases (69.7%). Gram-positive bacteria constituted 51.5% of isolates, predominantly Staphylococcus aureus and coagulase-negative staphylococci, while Gram-negative bacilli accounted for 21.2%. Fungal isolates (Candida species) represented 27.3% of cases. Gram-positive isolates showed complete sensitivity to vancomycin and linezolid, whereas Gram-negative organisms demonstrated multidrug resistance. ROC analysis showed good diagnostic accuracy for CRP (AUC = 0.87) and excellent accuracy for PCT (AUC = 0.98). At optimal cut-offs (CRP ≥14.27 mg/L; PCT ≥1.77 ng/mL), PCT demonstrated higher sensitivity and specificity than CRP. Conclusion: Gram-positive cocci were the predominant bacterial pathogens, with a notable proportion of fungal sepsis among neonates. Procalcitonin proved to be a more reliable biomarker than CRP for early diagnosis of neonatal septicaemia. Integration of biomarker assessment with microbiological surveillance may facilitate early detection, guide rational antimicrobial therapy, and improve management of neonatal sepsis.