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Evaluating the Impact of Antibiotic Exposures as Time-Dependent Variables on the Acquisition of Carbapenem-Resistant Acinetobacter baumannii. Crit Care Med 2016 Oct;44(10):e949-56



Pubmed ID




Scopus ID

2-s2.0-84966710980   13 Citations


OBJECTIVES: To determine the time-dependent effect of antibiotics on the initial acquisition of carbapenem-resistant Acinetobacter baumannii.

DESIGN: Retrospective cohort study.

SETTING: Forty-bed trauma ICU in Miami, FL.

PATIENTS: All consecutive patients admitted to the unit from November 1, 2010, to November 30, 2011.


MEASUREMENTS AND MAIN RESULTS: Patients underwent surveillance cultures at admission to the unit and weekly thereafter. The primary outcome was the acquisition of carbapenem-resistant A. baumannii on surveillance cultures. Daily antibiotic exposures during the time of observation were used to construct time-dependent variables, including cumulative exposures (in grams and daily observed doses [defined daily doses]). Among 360 patients, 45 (12.5%) became colonized with carbapenem-resistant A. baumannii. Adjusted Cox models showed that each additional point in the Acute Physiologic and Chronic Health Evaluation score increased the hazard by 4.8% (hazard ratio, 1.048; 95% CI, 1.010-1.087; p = 0.0124) and time-dependent exposure to carbapenems quadrupled the hazard (hazard ratio, 4.087; 95% CI, 1.873-8.920; p = 0.0004) of acquiring carbapenem-resistant A. baumannii. Additionally, adjusted Cox models determined that every additional carbapenem defined daily dose increased the hazard of acquiring carbapenem-resistant A. baumannii by 5.1% (hazard ratio, 1.051; 95% CI, 1.007-1.093; p = 0.0243).

CONCLUSIONS: Carbapenem exposure quadrupled the hazards of acquiring A. baumannii even after controlling for severity of illness.

Author List

Munoz-Price LS, Rosa R, Castro JG, Laowansiri P, Latibeaudiere R, Namias N, Tarima S


L Silvia Munoz-Price MD, PhD Professor in the Medicine department at Medical College of Wisconsin
Sergey S. Tarima PhD Associate Professor in the Institute for Health and Equity department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Acinetobacter Infections
Acinetobacter baumannii
Age Factors
Anti-Bacterial Agents
Drug Resistance, Bacterial
Intensive Care Units
Microbial Sensitivity Tests
Middle Aged
Retrospective Studies
Sex Factors
Time Factors
jenkins-FCD Prod-480 9a4deaf152b0b06dd18151814fff2e18f6c05280