<qa>  What is the purpose of this study?The purpose of this study is to review patients with E. coli infections at UPMC from January 1, 2004 to December 31, 2005 to determine if these infections have arisen in the community rather than in hospitals or nursing homes. The occurrence of such resistant isolates could be devastating if they were associated with bloodstream infection, such as sometimes accompanies urinary tract infection, since antibiotic resistant E. coli is not suspected in isolates coming from the community. 