Comparison of risk factors for recovery of Acinetobacter baumannii during outbreaks at two Kentucky hospitals, 2006

Objectives. Acinetobacter baumannii (A. baumannii) is a well-described cause of nosocomial outbreaks and can be highly resistant to antimicrobials. We investigated A. baumannii outbreaks at two Kentucky hospitals to find risk factors for Acinetobacter acquisition in hospitalized patients. Methods. We performed case-control studies at both hospitals. We defined a case as a clinical culture growing A. baumannii from a patient from August 1 to October 31, 2006 (Hospital A), or April 1 to October 31, 2006 (Hospital B). Results. Twenty-nine cases were identified at Hospital A and 72 cases were identified at Hospital B. The median case patient age was 42 years in Hospital A and 46 years in Hospital B. The majority of positive cultures were from sputum (Hospital A, 51.7%; Hospital B, 62.5%). The majority of case patients had multidrug-resistant A. baumannii (Hospital A, 75.9%; Hospital B, 70.8%). Using logistic regression, controlling for age and admitting location, mechanical ventilation (Hospital A odds ratio [OR] = 21.6; 95% confidence interval [CI] 3.5, 265.9; Hospital B OR=4.5, 95% CI 1.9, 11.1) was associated with A. baumannii recovery. Presence of a nonsurgical wound (OR=6.6, 95% CI 1.2, 50.8) was associated with recovery of A. baumannii at Hospital A. Conclusions. We identified similar patient characteristics and risk factors for A. baumannii acquisition at both hospitals. Our findings necessitate the importance of review of infection control procedures related to respiratory therapy and wound care.