case_images: PMC11070911_01
case_images: Rhodococcus equi malakoplakia cytomorphology and histochemical findings. (A) Papanicolaou stain 600x. (B) Hematoxylin and eosin stain 600x. (C) Acid-fast stain 600x. (D) Fite acid-fast stain 600x. (E) Gram stain 600x.
case_images: gr1.jpg
case_images: PMC11070911_01_gr1.jpg
case_images: fig0005
case_images: Histologically, Rhodococcus infections present as a necrotizing granulomatous pattern with numerous macrophages that contain coccobacilli (Fig. 1). Necrotizing granuloma producing infections similar to Rhodococcus include other members of the aerobic actinomycetes, Corynebacterium, and Mycobacterium.  Rhodococcus can stain positive on acid-fast stain (Fig. 1). Rhodococcus from other pathogens include the coccobacillary morphology of the organisms that can be visualized by Gram or silver stains (Fig. 1). Rhodococcus is classically gram-positive. (Fig. 1).