Bloodstream Infections in Intensive Care Units: Microbial Spectrum and Antibiogram From a Tertiary Care Hospital in Central India

TL;DR

This study examines bloodstream infections in ICU patients in central India, identifying common bacteria and their resistance to antibiotics.

Contribution

The study provides an updated antibiogram and microbial spectrum specific to ICU bloodstream infections in central India.

Findings

Gram-negative bacilli were the most common pathogens in bloodstream infections.

High resistance to cephalosporins and fluoroquinolones was observed among Gram-negative isolates.

Non-albicans Candida species were the majority of fungal isolates with notable azole resistance.

Abstract

Background: Bloodstream infections (BSIs) are a major cause of morbidity and mortality among critically ill patients, particularly in intensive care units (ICUs). Increasing antimicrobial resistance among bloodstream pathogens further complicates management and limits effective empirical therapy.

Methods: This retrospective observational study was conducted in the Department of Microbiology at a tertiary care teaching hospital in central India. Blood culture samples received from various ICUs over a one-year period (July 2024 to June 2025) were analyzed. Organisms were identified using standard microbiological methods, and antimicrobial susceptibility testing was performed using the Kirby-Bauer disk diffusion method in accordance with Clinical and Laboratory Standards Institute guidelines.

Results: Out of 740 blood culture samples processed, 245 (33.10%) yielded positive growth. Gram-negative bacilli were the predominant isolates (44.89%), followed by Gram-positive cocci (35.92%) and fungal pathogens (19.19%). Escherichia coli and Staphylococcus aureus were the most common Gram-negative and Gram-positive isolates, respectively. Non-albicans Candida species constituted the majority of fungal isolates. Gram-negative organisms showed high resistance to cephalosporins and fluoroquinolones, while carbapenems, colistin, and tigecycline demonstrated the highest in vitro activity. All Gram-positive isolates were susceptible to vancomycin and linezolid, while Candida isolates exhibited notable azole resistance with preserved susceptibility to amphotericin B.

Conclusion: This study highlights the predominance of Gram-negative pathogens and a substantial burden of multidrug resistance among ICU-associated BSIs. Regular surveillance of bloodstream pathogens and institution-specific antibiograms is essential to guide empirical therapy and support antimicrobial stewardship efforts in critical care settings.

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