Clinical Characteristics, Microbiological Profile and Antimicrobial Resistance Pattern of Bloodstream Infections in Critically Ill Patients: A Cross-sectional Study

Introduction: Bloodstream Infections (BSIs) often complicate the outcomes of critically ill patients and are typically associated with high morbidity and mortality rates. There is marked variation reported in the prevalence and antimicrobial resistance patterns of pathogens causing BSIs. Updated and comprehensive data, integrating the microbiological profile and clinical characteristics, may serve as a promising framework for planning and executing management strategies for BSIs in critically ill patients. Aim: To investigate the clinical characteristics, microbiological profile, and antimicrobial resistance patterns of BSIs in critically ill patients. Materials and Methods: This cross-sectional study was conducted over a period of four years (June 2021 to May 2025) in a tertiary care academic hospital. Blood cultures from adult patients (>18 years) with a strong clinical suspicion of sepsis were included. Sepsis was diagnosed based on the criteria for Systemic Inflammatory Response Syndrome (SIRS). Bacterial pathogens isolated from blood cultures were identified, and antimicrobial susceptibility testing was performed using the Kirby-Bauer disc diffusion test on Mueller-Hinton agar. The clinical characteristics of patients were recorded and analysed. Statistical analysis was performed using Statistical Package for the Social Sciences (SPSS) version 24.0 (IBM, USA). A p-value <0.05 was considered significant. Results: Out of 15,894 blood cultures received, a total of 2,764 (17.4%) were positive. Risk factors such as the use of corticosteroids and the presence of invasive medical devices were significantly associated with BSIs. Bacterial pathogens were isolated from 2,481 (89.8%) samples, while Candida was isolated from 283 (10.2%) samples. Coagulase-negative Staphylococci 411 (59.1%) were the most common Grampositive cocci (GPC). Klebsiella pneumoniae 642 (50.1%) was the most common Gram-negative bacilli (GNB). Both GPC and GNB demonstrated high resistance to commonly used first- and second-line antimicrobial agents. Conclusion: The overall prevalence of bacterial pathogens was high in BSIs among critically ill patients, with GNB—particularly Klebsiella pneumoniae—being the most prevalent pathogen. The significant antimicrobial resistance demonstrated by both Gram-positive and Gram-negative pathogens is alarming and emphasises the importance of strengthening infection prevention and control practices, along with the effective implementation of enhanced antimicrobial stewardship programs