Several rapidly growing mycobacteria (RGM) species have been described as etiologic agents of bacteremia in cancer patients with long-term central devices [1–5].We report here a series of cases of bacteremia caused by the novel species of RGM namedM. canariasense that were identified through a retrospective review of all cases in which at least one blood culture was positive for M. canariasense at a tertiary care hospital. Blood cultures performed using Bactec Vial–Aerobic Cultures (Becton–DickinsonMicrobiology Systems, Sparks, MD, USA) were incubated for a maximum of 15 days. Species assignation was done according to phenotypic and genotypic characteristics [6]. The agar disk elution method [7] was used to determine the susceptibility of the isolates to amikacin, tobramycin, imipenem, doxycycline, cefoxitin, and ciprofloxacin, and the E test (AB Biodisk, Solna, Sweden) [1] was used to test susceptibility to clarithromycin. The medical records of all patients from whom M. canariasense was isolated were examined, and clinical and microbiological data were obtained from their medical charts. A clinically significant case of bacteremia was defined when the following criteria were met: (a) presence of clinical symptoms such as fever (oral temperature of >38°C), chills or hypotension of acute onset at the time the blood specimens were taken; and (b) absence of another infectious cause that could explain the clinical symptoms. Definite catheter-related bacteremia was defined using the following criteria outlined previously by Raad et al. [2]: (a) clinical (or autopsy) and microbiological data disclosed no source of bacteremia other than the catheter; and (b) the same Mycobacterium species was recovered from the catheter tip (i.e., >15 cfu/catheter segment was recovered using the roll-plate semiquantitative culture technique). Probable catheter-related bacteremia was diagnosed if only the first criterion was fulfilled, and relapse was diagnosed when the same Mycobacterium species was isolated and clinical symptoms recurred after the end of therapy. To analyze concordance between the clinical classifications made according to the above criteria and the outcome of the clinical evaluation performed by the patient’s doctor (as reflected in the clinical chart), the Kappa index was measured; K>0.75 was considered excellent. The review identified 17 cases in which M. canariasense was isolated from blood between January 2000 and September 2002; in ten of these cases more than one blood culture was positive. Blood specimens were obtained via the indwelling catheters in all cases in which the drawing procedure was specified. Mycobacteria grew after the standard incubation period of 5 days in the blood culture bottles of 11 patients, and they were not isolated from any clinical specimens other than the blood or the catheter tip. All strains showed susceptibility to all antibiotics tested. M. canariasense was considered the etiologic agent of bacteremia in 12 of the 17 cases. The main characteristics of the patients are shown in Table 1. Eleven patients had received chemotherapy previously, eight had received transfusions, six were neutropenic, three had undergone bone marrow transplantation, three had received steroid therapy, and two had received parenteral nutrition. None of the patients had clinical evidence of tissue invasion. All 12 M. I. Campos-Herrero (*) . D. Garcia . P. Suarez Servicio de Microbiologia, Hospital Universitario de Gran Canaria Dr. Negrin, Barranco de la Ballena s/n, 35020 Las Palmas de Gran Canaria, Canary Islands, Spain e-mail: mcamnavl@gobiernodecanarias.org Tel.: +34-928-449518 Fax: +34-928-449292