Carbapenem's Role in Empiric and Directed Therapy for Bacterial Infections in Cardiothoracic Transplantation: Are All Carbapenems Created Equal?

The spectrum of potential pathogens in the cardiothoracic transplant recipient (CT TX) is vast and has varied over time with the evolution of novel immunosuppressant regimens, and with the exposure to both prophylaxis regimens employed to avert infections and increasingly resistant nosocomial and community acquired bacteria. Successful clinical management of a bacterial infection in the CT TX includes appropriate empiric therapy at the time of presentation of an infectious disease followed by directed therapy for the identified pathogen(s). The carbapenems play a major role in empiric or pathogen directed therapy in these patients due to their broad spectrum of activity to pathogens resistant to other classes of antibiotics and also atypical pathogens that can infect this cohort of patients, like Listeria and Nocardia spp. Carbapenems are a class of broad-spectrum β-lactam antibiotics consisting of Invanz® (ertapenem), Primaxin® (imipenem/cilastatin), Merrem® (meropenem), and Doribax® (doripenem). 1-4 This article aims to highlight the key differences that may influence therapeutic decisions by comparing and contrasting these carbapenems in terms of spectrum of activity, evolving resistance mechanisms, metabolism, pharmacokinetcs/dynamics properties, differing tissue penetration capabilities and adverse effects of the individual drugs.