"Health Care–Associated Infection After Red Blood Cell Transfusion"
JAMA
http://jama.jamanetwork.com/article.aspx?articleid=1853162 
"Conclusions and Relevance  Among hospitalized patients, a restrictive RBC transfusion strategy was associated with a reduced risk of health care–associated infection compared with a liberal transfusion strategy. Implementing restrictive strategies may have the potential to lower the incidence of health care–associated infection."