Rhodococcus equi is soil-dwelling bacteria that infects grazing animals. R. equi causes pneumonia in foals. Clinical disease is not common in horses older than 8 months. R. equi is a facultative intracellular, nonmotile, non–spore-forming, gram positive coccobacillus (may exist as a coccus or bacillus or intermediate form). Infection occurs by inhalation of soil particles containing pathogenic R. equi, effecting the respiratory system and causing pneumonia. R. equi has significant economic consequences due to mortality, prolonged treatment, surveillance for early detection, and expensive prophyl-actic strategies. The development of clinical disease is linked to the immune system of foals; production of little to no detectable interferon (IFN-) are at a higher risk of developing pneumonia.1 Manure from pneumonic foals is the primary source of R. equi, and has the ability to contaminate the environment. A mixture of antimicrobials is the preferred treatment of R. equi infection. R. equi is best diagnosed quickly using polymerase chain reaction (PCR in order to then stop spreading of disease by keeping infected horses isolated.2 The Fluxergy Rhodococcus equi assay qualitatively detects the pathogen in equine tracheal wash or feces.