A Clinico-Bacteriological Study of Neonatal Septicemia and Correlation with Inflammatory Markers C-Reactive Protein and Interleukin-6 in a Tertiary Care Hospital, Chennai

Background: Neonatal septicemia remains a leading cause of morbidity and mortality in developing countries. Early diagnosis is hampered by nonspecific clinical features and the limited sensitivity of blood cultures. Inflammatory markers such as C-reactive protein (CRP) and interleukin-6 (IL-6) have emerged as adjuncts for early detection. This study aimed to analyze the clinico-bacteriological profile of neonatal septicemia, characterize antimicrobial susceptibility patterns, and evaluate the correlation between clinical features, bacteriological findings, and inflammatory markers (CRP, IL-6) in a tertiary care hospital. Material and Methods: A prospective observational study was conducted on 150 neonates with suspected sepsis admitted to the neonatal intensive care unit (NICU) at Institute of Child Health & Hospital for Children, Chennai over a 12-month period. Demographic, perinatal, and clinical data were collected. Blood cultures were performed using conventional methods, and isolates were identified with standard microbiological techniques. Antimicrobial susceptibility was determined by the Kirby-Bauer disk diffusion method. Serum CRP and IL-6 levels were measured at admission. Statistical analysis included descriptive statistics, chi-square tests, and correlation analysis (Spearman/Pearson as appropriate) to assess relationships between clinical features, culture results, and inflammatory markers. Results: Of 150 neonates, 60% were male and 40% female; 58% were preterm and 42% term. Early-onset sepsis (EONS) accounted for 54%, and late-onset sepsis (LONS) for 46%. Blood culture positivity was 32%. The most common isolates were Klebsiella pneumoniae (28%), Coagulase-negative Staphylococcus (CONS, 22%), and Acinetobacter spp. (14%). Gram-negative isolates showed high resistance to ampicillin and third-generation cephalosporins but retained sensitivity to amikacin and meropenem. Gram-positive isolates were largely sensitive to vancomycin and linezolid. Median CRP and IL-6 levels were significantly higher in culture-positive cases (CRP: 48 mg/L vs. 18 mg/L; IL-6: 340 pg/mL vs. 110 pg/mL; p < 0.001). CRP and IL-6 showed a strong positive correlation (r = 0.68, p < 0.001), and both were significantly associated with adverse outcomes. Conclusion: Neonatal septicemia in this setting is characterized by a predominance of multidrug-resistant Gram-negative organisms. CRP and IL-6 are valuable adjuncts for early diagnosis and risk stratification, with combined use improving diagnostic accuracy. Regular surveillance of antimicrobial resistance and judicious antibiotic use are imperative for effective management and stewardship.

Keywords: Neonatal sepsis, C-reactive protein, Interleukin-6, Blood culture, Antimicrobial resistance, NICU.