Objective: The aim of this study was to determine the risk factors for healthcare-associated infections of IRPA in two intensive care units of a large academic teaching hospital.
Methods: A retrospective study was performed at The Ohio State University Medical Center in Columbus,
Results: Data from multivariate unconditional logistic regression analysis showed that independent risk factors for IRPA healthcare-associated infections were prescription of cephalosporins [OR 3.1, 95% CI 1.45-6.62], intravenous colistin [OR 4.88, 95% 1.76-13.49], imipenem [OR 3.83, 95% CI 1.58-9.26], and piperacillin [OR 10.02, 95% CI 4.26-23.55] during their ICU stay. Additionally exposure to imipenem within the 90 days prior to hospitalization [OR 4.51, 95% CI 1.19-17.07] and time at risk (OR 1.59, 95% CI .611-4.15] were also independent risk factors.
Conclusions: Healthcare-associated infection with IRPA is not caused by exposure to imipenem alone, but also exposure to cephalosporins and piperacillin. It is likely that colistin was added for treatment after imipenem resistance was determined. Imipenem exposure either during the hospitalization or within 90 days prior to IRPA infection still appears to provide significant risk. Limiting the use of a single agent, such as imipenem, may not be enough to reduce slow down escalating imipenem resistance.