Review Article Mycobacterium chimaera infections: An update Niccol  o Riccardi a, b, * , Jacopo Monticelli c , Roberta Maria Antonello d , Roberto Luzzati c , Marco Gabrielli e , Maurizio Ferrarese b, f , Luigi Codecasa b, f , Stefano Di Bella c , Daniele Roberto Giacobbe g a Department of Infectious -Tropical Diseases and Microbiology, IRCCS Sacro Cuore Don Calabria Hospital, Negrar, Verona, Italy b StopTB Italia Onlus, Milan, Italy c Infectious Diseases Department, Azienda Sanitaria Universitaria Integrata di Trieste, Trieste, Italy d School of Medicine, University of Trieste, Trieste, Italy e Cardiothoracic and Vascular Surgery Department, Azienda Sanitaria Universitaria Integrata di Trieste, Trieste, Italy f Regional TB Reference Centre and Laboratory, Villa Marelli Institute/ASST Niguarda Ca' Granda Hospital, Milan, Italy g Department of Health Sciences (DISSAL), University of Genoa, Genoa, Italy article info Article history: Received 9 June 2019 Received in revised form 15 October 2019 Accepted 13 November 2019 Available online xxx Keywords: Mycobacterium chimaera Infection Review Update abstract Mycobacterium chimaera is a non-tuberculous mycobacterium belonging to the Mycobacterium avium complex, described for the first time in 2004. It acts as an opportunistic pathogen, with infections, usually respiratory illnesses, occurring more frequently in immunocompromised patients or in patients with underlying respiratory diseases. During the last decade Mycobacterium chimaera disseminated in- fections following cardiothoracic surgery, especially open-heart surgery, have been increasingly reported worldwide. From a pathogenic standpoint, Mycobacterium chimaera is acquired during cardiopulmonary bypass via bioaerosols emitted from contaminated heater-cooler units water systems. Due to non- specific symptoms and long latency, postoperative Mycobacterium chimaera infections may not be promptly diagnosed and treated, and may become life-threatening. The indication for revision surgery needs to be carefully evaluated on a case-by-case basis, and antibiotic therapy should be based on drug susceptibility testing results. Our review aims to provide an updated account of microbiological char- acteristics, clinical presentation, diagnosis, and management of Mycobacterium chimaera infections, with a special focus on those developing after cardiothoracic surgery. © 2019 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved. Contents 1. Introduction ....................................................................................................................... 00 2. Methods ................................................................. ........................................................ 00 3. Microbiological characteristics and identification ....................................................................................... 00 4. Clinical presentation and diagnosis of M. chimaera infections ........................................ ................................... 00 4.1. Pulmonary disease .......................................................................................................... 00 4.2. Extrapulmonary manifestation ................................................................................................ 00 4.2.1. Infection after cardiothoracic surgery ................................................................................... 00 4.2.2. Prosthetic valve endocarditis ........................................................................................... 00 4.2.3. Vascular graft infection and surgical site infection ....................................................................... 00 4.2.4. Osteomyelitis ........................................................................................................ 00 4.2.5. Disseminated granulomatous disease ................................................................................... 00 * Corresponding author. Clinic of Infectious Diseases and Tropical Medicine, IRCCS Don Calabria Sacred Heart Hospital, Via Don A. Sempreboni, 5, 37024, Negrar, Verona, Italy. E-mail address: niccolo.riccardi@yahoo.it (N. Riccardi). Contents lists available at ScienceDirect Journal of Infection and Chemotherapy journal homepage: http://www.elsevier.com/locate/jic https://doi.org/10.1016/j.jiac.2019.11.004 1341-321X/© 2019 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved. J Infect Chemother xxx (xxxx) xxx Please cite this article as: Riccardi N et al., Mycobacterium chimaera infections: An update, J Infect Chemother, https://doi.org/10.1016/ j.jiac.2019.11.004