Botryomycosis is caused by:
**Core Concept**
Botryomycosis is a chronic granulomatous bacterial infection characterized by the formation of granules within the infected tissue, resembling a fungal infection due to its histopathological appearance. This condition is often mistaken for other types of infections or neoplastic processes.
**Why the Correct Answer is Right**
Botryomycosis is primarily caused by Staphylococcus aureus, a Gram-positive bacterium. The bacteria produce a protein called staphylococcal exfoliative toxin, which leads to the formation of granules within the infected tissue. This unique histopathological appearance is responsible for the condition's name, which is derived from the Greek words "botrys" meaning "bunch of grapes" and "mykes" meaning "fungus." The granules are composed of bacterial debris, cellular debris, and a proteinaceous matrix.
**Why Each Wrong Option is Incorrect**
**Option A:** Streptococcus pyogenes is a Gram-positive bacterium that causes streptococcal infections, such as pharyngitis and skin infections, but it is not associated with botryomycosis.
**Option B:** Pseudomonas aeruginosa is a Gram-negative bacterium that causes opportunistic infections, particularly in immunocompromised patients, but it is not the primary cause of botryomycosis.
**Option C:** Aspergillus fumigatus is a fungus that causes aspergillosis, a type of fungal infection that affects the lungs, but it is not associated with botryomycosis.
**Clinical Pearl / High-Yield Fact**
Botryomycosis should be considered in the differential diagnosis of chronic infections, particularly in patients with a history of trauma or surgery, as it can mimic other conditions such as actinomycosis or tuberculosis.
**Correct Answer:** C. Staphylococcus aureus.