Risk factors for piperacillin/tazobactam-resistant Escherichia coli in ICU patients: a clinical study.

Objective: To determine risk factors of infections with piperacillin/tazobactam-resistant Escherichia coli in critical care patients.

Design: Prospective, consecutive sample survey study.

Setting: Surgical intensive care unit (ICU) in a university hospital.

Patients: A consecutive series of 133 patients from whom culture results were positive for E. coli during their ICU stay.

Interventions: None.

Measurements And Main Results: Multivariate logistic regression analysis identified the following significant independent factors associated with the emergence of a piperacillin/tazobactam-resistant Escherichia coli: prior use of amoxicillin (odds ratio, 4.15) and amoxicillin/clavulanate (odds ratio, 3.25).

Conclusions: Treatment with amoxicillin or amoxicillin/clavulanate is a major risk factor for the detection of piperacillin/tazobactam-resistant E. coli in ICU patients.