An aerobic gram-positive rod known to cause bacteremia in hospitalized immunocompromised patients is which species?

• A. Bacillus anthracis
• B. Corynebacterium jeikeium
• C. Corynebacterium ulcerans
• D. Corynebacterium urealyticum

Answer: (B)

In immunocompromised patients who are hospitalized, bloodstream infections often arise from skin-associated gram-positive rods that colonize indwelling devices. Corynebacterium jeikeium fits this scenario well: it is a non-spore-forming, aerobic gram-positive rod that is part of normal skin flora and is a well-known cause of nosocomial bacteremia, especially in patients with catheters or prosthetic devices. It tends to be multidrug resistant, so clinicians often choose vancomycin for treatment.

The other organisms listed don’t fit as cleanly. Bacillus anthracis is a spore-forming rod that causes anthrax and isn’t a typical cause of nosocomial bacteremia. Corynebacterium urealyticum is more commonly linked to urinary tract infections and encrusted ureitis, not the classic picture of catheter-associated bacteremia. Corynebacterium ulcerans is primarily a zoonotic pathogen that can cause diphtheria-like illness, with bacteremia being far less characteristic.

Thus, Corynebacterium jeikeium is the best match for an aerobic gram-positive rod causing bacteremia in hospitalized immunocompromised patients.