Nosocomial outbreak of Microbacterium species bacteremia among cancer patients

To date, only 6 sporadic Microbacterium species (formerly coryneform Center s for Disease Control and Prevention [CDC] groups A-4 and A-5) infections h ave been reported. The source, mode of transmission, morbidity, mortality, and potential for nosocomial transmission of Microbacterium species remain unknown. From 26 July through 14 August 1997, 8 episodes of coryneform CDC group A-5 symptomatic bacteremia occurred in 6 patients on the oncology war d at the Maine Medical Center. One patient died. All isolates were identifi ed at CDC as Microbacterium species and had identical DNA banding patterns by pulsed-field gel electrophoresis. To assess risk factors for Microbacter ium species infection, a retrospective cohort study was conducted. The pres ence of a central venous catheter was the strongest risk factor (6/6 vs. 22 /48; relative risk, 3.2; P < .0001). This outbreak demonstrates significant Microbacterium species-associated morbidity and mortality in immunocomprom ised populations and confirms the potential for epidemic nosocomial transmi ssion.