Etiological profile and antimicrobial susceptibility pattern of blood culture isolates for bloodstream infection

Abstract

Objectives: The objective of the study is to identify and study the antimicrobial susceptibility pattern of various causative agents of bloodstream infection (BSI) in a tertiary care hospital. Materials and Methods: This was a retrospective observational study conducted from October 2022 to September 2023. Paired blood culture samples were collected aseptically and incubated in BD BACTEC FX-40, a fully automated blood culture system, for 5 days. When the bottle was “flagged positive,” gram staining was done, followed by subculture onto Blood agar and MacConkey agar. Species identification and antibiotic susceptibility testing were performed using the VITEK 2 Compact system and interpreted according to Clinical Laboratory Standard Institute guidelines. Statistical analysis: The data were analyzed using the Statistical Package for the Social Sciences version 20.0. Results: 10,449 blood cultures were received during the 1-year study period, out of which 13.2% (1378 samples) showed growth of pathogenic organisms. Gram-negative bacilli (810/1,378, 58.8%) were the most common etiological agents, and Klebsiella pneumoniae was the most predominant pathogen recovered . Candida spp. were recovered in (150/1378, 10.9%) isolates. A high rate of antimicrobial resistance (AMR) was noted, including (26/46, 56.5%) methicillin-resistant Staphylococcus aureus, (9/125, 7.2%) vancomycin-resistant enterococci, and (269/536, 50.2%) carbapenem-resistant enterobacterales. The current study also highlights high resistance among non-fermenting Gram-negative bacteria. Conclusions: Gram-negative bacilli are the most common cause of BSIs in our setup. A high level of AMR is observed among the pathogens. The formulation of an effective antimicrobial stewardship program and its strict compliance is the need of the hour.