Bacteremia Due to Arthrobacter creatinolyticus in an Elderly Diabetic Man with Acute Cholangitis.

An 87-year-old man with poorly controlled diabetic mellitus presented with fever, bedsores, and elevated hepatobiliary enzyme levels. He was diagnosed with bacteremia with acute cholangitis due to Arthrobacter species, which are Gram-positive, aerobic, catalase-positive, coryneform bacteria belonging to the family Microbacteriaceae. Doripenem and subsequencial sulbactam/ampicillin treatment were used for the acute cholangitis, and the bacteremia was treated with a 2-week course of vancomycin. The bacteremia was misidentified by the phenotyping assay (API Coryne test), but was identified as Arthrobacter creatinolyticus by 16S rRNA and matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry. To our knowledge, this is the first report of a human case of A. creatinolyticus bacteremia.