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Published on: February 23, 2014
Changes In Lower Respiratory Tract Bacterial Isolates In ICU Patients Before and After the COVID-19 Pandemic
Mahmut Ulger1, Serif Kurtulus2, Remziye Can3
1Department of Chest Diseases, University of Harran Faculty of Medicine; mahsur8463@gmail.com.
Journal of Visualized Experiments : Jove
|June 29, 2026
Summary
The COVID-19 pandemic altered bacterial pathogen distribution in intensive care units, with decreased detection of key bacteria like Klebsiella pneumoniae and Pseudomonas aeruginosa post-pandemic. Mortality rates also declined.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Critical Care Medicine
Background:
- The COVID-19 pandemic significantly impacted healthcare, potentially altering patterns of bacterial infections in intensive care units (ICUs).
- Understanding changes in bacterial pathogen distribution is crucial for effective infection control and patient management.
Purpose of the Study:
- To compare the prevalence of bacterial pathogens in lower respiratory tract infections among COVID-19-negative ICU patients before and after the onset of the COVID-19 pandemic.
- To identify shifts in the detection rates of specific bacterial species and their association with patient outcomes.
Main Methods:
- Retrospective analysis of culture results from 1,665 COVID-19-negative ICU patients admitted to a university hospital chest diseases ICU.
- Specimens were cultured using standard microbiological techniques, and data were classified as pre-COVID-19 or post-COVID-19 (from March 2020).
- Logistic regression was employed to analyze changes in pathogen detection rates and mortality.
Main Results:
- Microbial growth was detected in 48.9% of samples, with a higher proportion from the pre-COVID-19 period.
- Acinetobacter baumannii remained the most frequent isolate in both periods.
- Significantly reduced detection rates were observed for Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli in the post-COVID-19 period (odds ratios ≈0.3-0.4).
- Mortality rates were lower in the post-COVID-19 period.
Conclusions:
- The COVID-19 pandemic was associated with a decrease in the detection of several common bacterial pathogens in lower respiratory tract infections among non-COVID-19 ICU patients.
- These changes may be linked to altered infection control practices during the pandemic, though causality requires further investigation.
- Despite shifts in specific pathogen prevalence, overall pathogen diversity remained similar, and mortality decreased post-pandemic.
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