A 78-year-old hospitalized patient with a catheter presents with fever; Gram-positive pleomorphic rods; BAP shows white pinpoint colonies; Catalase positive; Motility non-motile. What organism are you suspecting?

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When a catheterized, hospitalized patient has fever and the Gram stain shows Gram-positive pleomorphic rods that are catalase positive and nonmotile, the pattern fits Corynebacterium species, especially Corynebacterium jeikeium. This organism is part of normal skin flora but acts as an opportunistic pathogen in people with indwelling devices, leading to device-related infections. It forms small white pinpoint colonies on blood agar and is nonmotile, which helps distinguish it from other Gram-positive rods.

Listeria monocytogenes, while a Gram-positive rod, is motile at room temperature and often shows tumbling motility; it also tends to cause invasive disease in specific settings (neonates, pregnant people, or severely immunocompromised) rather than catheter-associated bacteremia. Corynebacterium diphtheriae can appear as Gram-positive pleomorphic rods but is associated with respiratory disease and requires special media or toxigenicity testing rather than a typical device-related bloodstream infection. Staphylococcus epidermidis is a Gram-positive cocci, not rods, so the morphology already points away from it.

Thus the combination of pleomorphic, nonmotile, catalase-positive Gram-positive rods that produce small white colonies on blood agar in this clinical context most strongly supports Corynebacterium jeikeium.