Tissue and serum samples will then be sent to David P. Nicolau, PhD, FCCP, FIDSA, at the Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, Connecticut. Samples will be batched and sent all together at the completion of study enrollment. Dr. Swank and the study nurse will be responsible for securely packing samples on dry ice and overnight shipping them to Dr. Nicolau. Once with Dr. Nicolau, the tissue samples will be homogenized and analyzed to determine zones of inhibition. The Cefazolin concentrations will be determined in the serum samples using a previously validated high-performance liquid chromatography method. 16 Tissues and serum will be sent without direct identifiers. Dr. Nicolau will not have access to the identity of the research subjects providing the samples.