DOI: 10.38053/acmj.1952013 ISSN: 2718-0115

Antimicrobial resistance of Gram-negative bacteria in intensive care unit-weighted blood culture isolates: a four-year retrospective single-center analysis covering the pandemic period

Safiye Göçer, Barış Ecevit Yüksel
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Aims: This study, covering the period 2020-2023, examined the species distribution and resistance dynamics of Gram-negative bloodstream infections detected in a tertiary hospital. The study aims to contribute to region-specific empirical treatment approaches by revealing changes in resistance, particularly in intensive care units (ICUs).Methods: Blood cultures collected at a tertiary hospital between January 2020 and December 2023 were retrospectively evaluated. The species distribution and antimicrobial resistance profiles of Gram-negative bacteria isolated from positive blood cultures were examined. Species identification and antibiotic susceptibility testing were performed using the BD Phoenix 100 system, and the results were evaluated according to EUCAST criteria. Repeated isolates were excluded. Appropriate parametric and non-parametric tests were used in the statistical analyses.Results: Of the 528 Gram-negative isolates examined, 83.5% were obtained from ICUs, with the most frequently isolated species being Klebsiella pneumoniae (K. pneumoniae) (25.8%), Acinetobacter baumannii (A. baumannii) (21.2%), and Escherichia coli (15.3%). Resistance rates were significantly higher in ICU isolates compared to ward isolates; imipenem resistance in K. pneumoniae showed a significant increase over the years (p=0.001), while resistance rates in A. baumannii isolates remained stable above 80% against all antibiotics. Amikacin exhibited the highest susceptibility rate (61.8%) among Enterobacterales isolates. Conclusion: The high resistance burden of Gram-negative bacteria originating from ICUs necessitates updating empirical treatment protocols with local surveillance data. Given the increasing resistance observed in K. pneumoniae and A. baumannii, active surveillance and rational antibiotic use are critical to limiting the spread of resistant strains.

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