A gram-positive bacillus was isolated repeatedly from blood taken through the lumina of a central venous catheter of a patient with multiple myeloma who developed febrile neutropenia following chemotherapy. The bacterium was identified by the API CORYNE system as 'Corynebacterium aquaticum'. Gene analysis targeting the 16S rRNA indicated that the organism had a 99.5% identity with Aureobacterium liquefaciens although there were two phenotypic characteristics at variance with the description of this species. Problems remain with the routine identification of 'C. aquaticum' and Aureobacterium species. The few clinical reports on patients infected with 'C. aquaticum' and A. liquefaciens indicate that these are rare infections often associated with immunocompromise.