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Published on: August 4, 2023
The impact of Acinetobacter baumannii infections on outcome in trauma patients: a matched cohort study
Barbara M Eberle1, Beat Schnüriger, Bradley Putty
1Division of Trauma Surgery and Critical Care at Los Angeles County and University of Southern California Medical Center, Los Angeles, CA, USA.
Objective:
To determine the impact of Acinetobacter baumannii infection on the outcome of trauma patients.
Design And Setting:
A retrospective 1:2-matched cohort study. Level I trauma intensive care unit patients with confirmed Acinetobacter baumannii infection were defined as cases.
Patients:
Thirty-one Acinetobacter baumannii patients were matched to 62 controls with evidence of infection caused by other microorganisms.
Measurements And Main Results:
There were 12 matching criteria, including focus of infection, demographics, severity, and characteristics of injury. In-hospital mortality rate, intensive care unit length of stay, and complications of Acinetobacter baumannii including multidrug-resistant strains in patients were compared to those of their controls; 81% had hospital-acquired pneumonia, 13% had bloodstream infections, and 6% had urinary tract infections in both groups. Acinetobacter baumannii cultures were multidrug resistant in 42% (13/31) of cases. The initial empirical antibiotic therapy was adequate in 71% (22/31). Although the in-hospital mortality was higher in the Acinetobacter baumannii group (16% vs. 13%; odds ratio, 1.23; 95% confidence interval, 0.38-4.36; p = .67), the difference did not reach statistical significance. Using the test of equivalence or clinical indifference, the impact of an Acinetobacter baumannii infection on mortality is inconclusive. This applies also to multidrug-resistant strains. Overall intensive care unit stay was prolonged for Acinetobacter baumannii when compared to controls (median, [range], 28 [7-181] days vs. 17 [2-130] days, respectively; p = .05). ARDS and acute liver failure were more frequent in the Acinetobacter baumannii group compared to the control group (35% vs. 15%; odds ratio, 3.24; 95% confidence interval, 1.17-5.48; p = .02 and 26% vs. 10%; odds ratio, 3.25; 95% confidence interval, 3.25-10.40; p = .04).
Conclusions:
In this single-center experience, Acinetobacter baumannii infection, including multidrug-resistant strains, has inconclusive impact on mortality in a cohort of trauma patients. Larger studies are needed to support a definite conclusion. Acinetobacter baumannii infection was, however, associated with a longer intensive care unit stay and a higher rate of organ failure.
Insights
Acinetobacter baumannii infection in trauma patients did not significantly impact mortality but led to longer ICU stays and increased organ failure. Multidrug-resistant strains showed similar inconclusive effects on survival.
Area of Science:
- Infectious Diseases
- Critical Care Medicine
- Trauma Surgery
Background:
- Acinetobacter baumannii is a significant pathogen in healthcare-associated infections.
- Trauma patients are susceptible to severe infections, including those caused by Acinetobacter baumannii.
- Understanding the impact of Acinetobacter baumannii on trauma outcomes is crucial for effective patient management.
Purpose of the Study:
- To investigate the effect of Acinetobacter baumannii infection on mortality and morbidity in intensive care unit (ICU) trauma patients.
- To compare outcomes between trauma patients with Acinetobacter baumannii infections and those with other microbial infections.
- To assess the influence of multidrug-resistant Acinetobacter baumannii strains on patient outcomes.
Main Methods:
- Retrospective 1:2-matched cohort study design.
- Inclusion of Level I trauma ICU patients with confirmed Acinetobacter baumannii infection (cases) matched with controls infected by other microorganisms.
- Comparison of in-hospital mortality, ICU length of stay, and complications between the groups.
Main Results:
- No statistically significant difference in in-hospital mortality between Acinetobacter baumannii and control groups (16% vs. 13%).
- Acinetobacter baumannii infection was associated with a significantly longer ICU stay (median 28 vs. 17 days; p = .05).
- Higher rates of Acute Respiratory Distress Syndrome (ARDS) and acute liver failure were observed in the Acinetobacter baumannii group.
Conclusions:
- Acinetobacter baumannii infection, including multidrug-resistant strains, has an inconclusive impact on mortality in trauma patients.
- Acinetobacter baumannii infection is linked to prolonged ICU stays and increased incidence of organ failure in trauma patients.
- Larger studies are required to definitively establish the mortality impact of Acinetobacter baumannii in this population.
