Infections caused by multidrug resistant bacteria have become more prevalent at many tertiary care and academic centers. These infections are associated with increased morbidity and mortality. The initial empiric antibiotic choice may not be adequate and delay in initiating appropriate therapy is a reason for poorer outcomes. Furthermore, not uncommonly the only therapeutic options available are associated with significant toxicity. This is a particular challenge for solid organ transplant recipients, who are immunosuppressed and have a higher risk of acquiring infections. Exposure to different classes of antibiotics has been linked to development of antibiotic resistance. Determining the risk factors for acquisition of drug-resistant bacteria and the molecular mechanisms by which resistance occurs would allow the development and implementation of strategies to minimize these infections and therefore improve outcomes. We, the researchers at the University of Pittsburgh, aim to collect surveillance cultures on patients undergoing liver, intestinal and multivisceral transplantation in order to determine the prevalence and risk factors for Pseudomonas aeruginosa (P. aeruginosa), extended-spectrum β-lactamases (ESBL)-Klebsiella and methicillin-resistant Staphylococcus aureus (MRSA), as well as determine the molecular mechanisms associated with the development of resistance in P. aeruginosa.