Accepted for Publication: January 22, 2013.
Published Online: August 21, 2013. doi:10.1001/jamasurg.2013.2246.
Acquisition of data: Shepard, Carlson, Hadhazy.
Analysis and interpretation of data: Shepard, Ward, Milstone, Frederick, Perl.
Drafting of the manuscript: Shepard, Frederick, Perl.
Critical revision of the manuscript for important intellectual content: Ward, Milstone, Carlson, Frederick, Hadhazy, Perl.
Statistical analysis: Shepard, Frederick.
Administrative, technical, or material support: Shepard, Ward, Carlson, Frederick, Hadhazy, Perl.
Study supervision: Milstone, Perl.
Conflict of Interest Disclosures: None reported.
Additional Contributions: We acknowledge the assistance provided by Paul Allen, BS, and Kathleen Speck, MPH, from The Johns Hopkins Hospital; the infection preventionists throughout The Johns Hopkins Health System; John McGready, PhD, from the Johns Hopkins Bloomberg School of Public Health; and Jamie Shepard, BA, MS.