Acinetobacter baumannii infections in a surgical intensive care unit: predictors of multi-drug resistance
Stilianos Katsaragakis1, Haridimos Markogiannakis, Konstantinos G Toutouzas
1Surgical Intensive Care Unit, 1st Department of Propaedeutic Surgery, Hippokrateion Hospital, Athens Medical School, University of Athens, Athens 11527, Greece.
Objectives:
This study was designed to evaluate Acinetobacter baumannii infections incidence in our Surgical Intensive Care Unit, clinical features and outcome of these patients, and multi-resistance incidence to identify predictors of such a resistance.
Methods:
Prospective study of all patients with ICU-acquired Acinetobacter baumannii infection from June 1, 2003 to May 31, 2005. Patients with multi-resistant infection, susceptible exclusively to colistin, were compared with those sustaining non-multi-drug resistant infection.
Results:
Among 411 patients, 52 (12.6%) developed Acinetobacter infection. Their mean age was 66.3 +/- 8.4 years and APACHE II 20.4 +/- 7.3 (men: 51.9%). Infection sites were: bloodstream (46.2%), respiratory tract (32.7%), central venous catheter (11.5%), surgical site (7.7%), and urinary tract (1.9%). High multi-resistance (44.2%), morbidity (63.4%), and mortality (44.2%) were identified. Colistin was the most effective antibiotic (100% susceptibility), whereas resistance against all other antibiotics was >60%. Previous septic shock (p = 0.04), previous adult respiratory distress syndrome (ARDS) (p = 0.01), number of previous antibiotics (p = 0.01), previous aminoglycoside use (p = 0.04), and reoperation (p = 0.01) were risk factors for multi-resistance in univariate analysis. Morbidity in the multi-resistant group was significantly higher than the non-multi-resistant group (82.6% vs. 48.2%, p = 0.02). Mortality in the multi-resistant group also was higher; however, this difference did not marginally reach statistical significance (60.8% vs. 31.1%, p = 0.06). Multivariate analysis identified previous septic shock (p = 0.04; odds ratio (OR), 9.83; 95% confidence interval (CI), 1.003-96.29) and reoperation (p = 0.01; OR, 8.45; 95% CI, 1.52-46.85) as independent predictors of multi-resistance.
Conclusion:
Acinetobacter baumannii infections are frequent and associated with high morbidity, mortality, and multi-resistance. Avoidance of unnecessary antibiotics is a high priority, and specific attention should be paid to patients with previous ARDS and, particularly, previous septic shock and reoperation. When such risk factors are identified, colistin may be the only appropriate treatment.
Insights
Acinetobacter baumannii infections are common in surgical ICUs, leading to high morbidity and mortality, especially with multi-drug resistance. Previous septic shock and reoperation are key predictors of resistance, highlighting the need for judicious antibiotic use and colistin consideration.
Area of Science:
- Infectious Diseases
- Critical Care Medicine
- Microbiology
Background:
- Acinetobacter baumannii is a significant cause of hospital-acquired infections, particularly in intensive care units.
- Multi-drug resistance in Acinetobacter baumannii poses a major therapeutic challenge, limiting treatment options.
Purpose of the Study:
- To determine the incidence, clinical features, and outcomes of Acinetobacter baumannii infections in a Surgical Intensive Care Unit (SICU).
- To identify predictors of multi-drug resistance in Acinetobacter baumannii infections and assess the efficacy of colistin.
Main Methods:
- A prospective study was conducted over two years, enrolling patients with ICU-acquired Acinetobacter baumannii infections.
- Patients with multi-resistant infections were compared to those with non-multi-drug resistant infections, with a focus on colistin susceptibility.
Main Results:
- Acinetobacter baumannii infections occurred in 12.6% of patients, with high rates of multi-resistance (44.2%), morbidity (63.4%), and mortality (44.2%).
- Colistin demonstrated 100% susceptibility, while resistance to other antibiotics exceeded 60%.
- Previous septic shock and reoperation were identified as independent predictors of multi-drug resistance.
Conclusions:
- Acinetobacter baumannii infections are frequent in SICU settings and associated with substantial morbidity and mortality.
- Judicious antibiotic use is crucial, and patients with risk factors like previous septic shock, adult respiratory distress syndrome (ARDS), and reoperation require close monitoring.
- Colistin emerges as a critical treatment option for multi-resistant Acinetobacter baumannii infections.
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