Sion, and Four Sets of Cultures of Blood Obtained during the Hospitaliza- Endocarditis with Resolution of Symptoms. given the Polymicrobial Although Mycobacterial Infection of Permanent Indwelling Catheters

Both previously reported cases of M. neoaurum infection inbe noted that the biochemical description of M. neoaurum has varied in the literature depending on the strains being evaluated [1, 7, 8]; for volved infection of long-term indwelling Hickman catheters in immunocompromised hosts [2, 3]. One patient had a history of the case described herein as well as the two previously reported cases, identification of the bacterium was confirmed by reference laboratories. ovarian cancer and was parenteral nutrition-dependent [2]; the second patient was neutropenic secondary to receiving an allogeneic Although M. neoaurum is an uncommon isolate, it should be considered as a possible pathogen when isolated in the setting of bone marrow transplant [3]. The first patient was treated with intravenous gentamicin and cefoxitin through her Hickman cathea Hickman catheter infection in patients with long-term indwelling catheters. The optimal antibiotic regimen for this infection has not ter for 7 weeks and was without relapse at 18 months’ follow-up; her Hickman catheter was not removed [2]. The second patient been determined. However, the bacterium demonstrates susceptibility to multiple antibiotics in in vitro testing [2, 3]. defervesced within 24 hours of initiation of tobramycin and ticarcillin/clavulanate, but cultures of blood obtained from the Hickman catheter remained positive after 7 days of intravenous antibiotics, Sarah L. George and Larry S. Schlesinger and the catheter was removed. Antibiotic therapy was continued Division of Infectious Diseases, Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City, Iowa until the patient recovered from the neutropenia; he was without evidence of recurrent infection after 9 months of follow-up. A review of the University of Iowa’s mycobacteriology records References revealed an additional case of M. neoaurum bacteremia accompa1. Tsukamura M. A new species of rapidly growing, scotochromogenic myconying polymicrobial gram-negative endocarditis in an intravenous bacteria. Mycobacterium neoaurum. Medicine and Biology (Tokyo) drug user. A central venous catheter was placed on the day of admis1972;85:229–33. sion, and four sets of cultures of blood obtained during the hospitaliza2. Davison MB, McCormack JG, Blacklock ZM, Dawson DJ, Tilse MH, Crimtion yielded four separate organisms: two species of Pseudomonas mins FB. Bacteraemia caused by Mycobacterium neoaurum. J Clin Microbiol 1988;26:762–4. aeruginosa, Comamonas acidovorans, and M. neoaurum. The pa3. Holland DJ, Chen SC, Chew WW, Gilbert GL. Mycobacterium neoaurum tient’s central access site was changed and he was treated with 6 infection of a Hickman catheter in an immunosuppressed patient. Clin weeks of intravenous piperacillin and gentamicin for gram-negative Infect Dis 1994;18:1002–3. endocarditis with resolution of symptoms. Given the polymicrobial 4. Wallace RJ, Swenson JM, Silcox VA, Good RC, Tschen JA, Stone MS. nature of his bacteremia, it is difficult to determine what pathogenic Spectrum of disease due to rapidly growing mycobacteria. Rev Infect role if any the M. neoaurum played. Dis 1983;5:657–79. Although mycobacterial infection of permanent indwelling catheters 5. Flynn PM, Van Hooser B, Gigliotti F. Atypical mycobacterial infections has been described in association with species such as Mycobacterium of Hickman catheter exit sites. Pediatr Infect Dis 1988;7:510–3. fortuitum and Mycobacterium chelonae [4–6], M. neoaurum, when 6. Raad II, Vartivarian S, Khan A, Bodey GP. Catheter-related infections caused by the Mycobacterium fortuitum complex: 15 cases and review. encountered, has usually been considered nonpathogenic. We describe Rev Infect Dis 1991;13:1120–5. herein only the third reported case. It is striking that all three cases 7. Saito H, Gordon RE, Juhlin I, et al. Cooperative numerical analysis of involved infection of long-term indwelling Hickman catheters. Both rapidly growing mycobacteria: the second report. Int J Syst Bacteriol patients reported from Australia were immunocompromised before 1977;27:75–85. infection; our patient was not. Two of the three cases resolved with 8. Tsukamura M, Mizuno S, Tsukamura S. Numerical analysis of rapidly removal of the Hickman catheters, and one patient was successfully growing, scotochromogenic mycobacteria, including Mycobacterium treated through the catheter. No relapses have been reported. Unlike obuense sp. nov., nom. rev., Mycobacterium rhodesiae sp. nov., nom. catheter infections due to M. chelonae and M. fortuitum [4–6], none rev., Mycobacterium aichiense sp. nov., nom. rev., Mycobacterium chuof the three reported cases of M. neoaurum infection required debridebuense sp. nov., nom. rev., and Mycobacterium tokaiense sp. nov., nom. rev. Int J Syst Bacteriol 1981;31:263–75. ment of infected tissue surrounding the catheter-insertion site. It should