Reducing Blood Culture Contamination: a Prospective Crossover Study

Bloodstream infections cause significant morbidity and mortality and their prompt identification is an essential part of modern medicine. False positive results in blood cultures are primarily due to contaminants. It has been estimated that up to 50% of positive blood cultures represent contamination. These false positive cultures, at the microbiological laboratory level, require significant additional resources for workup. Additionally, they result in unnecessary antibiotic treatment and hospitalization days, causing needless harm to patients. Various methods have been implemented in order to reduce blood culture contaminants, including modifying the solution used for sterilizing the skin and feedback on contamination rates. However, it has been shown that the bacteria which colonize the human skin are not only on the surface but in fact colonize deeper surfaces as well. The SteriPath device diverts the initial 1-2 ml blood so as to remove any potential skin plug with contaminants. Thus, the principle object of this study is the determination of the rate of contamination of blood culture taken prior to initiating intervention versus the rate of contamination using three interventions: Monthly feedback via departmental report card, a chlorhexidine plus alcohol wipe and the SteriPath device. Secondary objectives will include ease of use of the wipes and the SteriPath device and an estimate of the sensitivity of SteriPath device use to true bacteremia. If the various interventions will be shown to reduce contamination, researchers will also attempt to estimate the financial effects of those reductions, comparing intervention cost to estimated savings related to reduced contamination.