Cairns, K.A.Hall, V.Martin, G.E.Griffin, D.W.J.Stewart, J.D.Khan, S.F.Abbott, I.J.Meher-Homji, Z.Morrissey, C.O.Sia, C.Love, J.Corallo, C.E.Bergin, P.Sharma, A.Gopal, B.Spencer, A.Peleg, A.Y.2021-06-242021-06-242020Transplant Infectious Disease, 2020; 23(2):1-101398-22731399-3062http://hdl.handle.net/2440/130943Infections caused by carbapenemase-producing Enterobacteriaceae (CPE) are an emerging threat in both solid organ and stem cell transplant recipients. Invasive CPE infections in transplant recipients are associated with a high mortality, often due to limited therapeutic options and antibacterial toxicities. One of the most therapeutically challenging group of CPE are the metallo-β-lactamase (MBL)-producing Gram-negative bacteria, which are now found worldwide, and often need treatment with older, highly toxic antimicrobial regimens. Newer β-lactamase inhibitors such as avibactam have well-established activity against certain carbapenemases such as Klebsiella pneumoniae carbapenemases (KPC), but have no activity against MBL-producing organisms. Conversely, aztreonam has activity against MBL-producing organisms but is often inactivated by other co-existing β-lactamases. Here, we report four cases of invasive MBL-CPE infections in transplant recipients caused by IMP-4-producing Enterobacter cloacae who were successfully treated with a new, mechanism-driven antimicrobial combination of ceftazidime/avibactam with aztreonam. This novel antimicrobial combination offers a useful treatment option for high-risk patients with CPE infection, with reduced drug interactions and toxicity.en© 2020 Wiley Periodicals LLC.E. cloacaeMBLantimicrobial resistanceantimicrobialsmetallo-beta-lactamaseJournal article100003121910.1111/tid.135100005954797000012-s2.0-85097076773557320Gopal, B. [0000-0002-8586-8743]