Which of the following is not true of Actinomycosis-
**Core Concept**
Actinomycosis is a rare, chronic, and granulomatous bacterial infection caused by Actinomyces species, typically Actinomyces israelii. It primarily affects the face and neck, but can also involve the lungs, gastrointestinal tract, and other organs. Actinomycosis is characterized by the formation of abscesses and sinus tracts that drain a characteristic "sulfur granule"-containing discharge.
**Why the Correct Answer is Right**
The correct answer is not explicitly given, so I will assume the options are:
A. Actinomycosis is caused by a gram-positive, anaerobic bacterium.
B. Actinomycosis typically presents with a chronic, indolent course.
C. Actinomycosis is often associated with dental caries or oral trauma.
D. Actinomycosis is usually treated with a course of antibiotics.
The correct answer is likely A, as Actinomyces species are gram-positive, facultatively anaerobic bacteria, not strictly anaerobic. The other options are true of Actinomycosis: it typically presents with a chronic, indolent course (B), is often associated with dental caries or oral trauma (C), and is usually treated with a course of antibiotics (D).
**Why Each Wrong Option is Incorrect**
**Option A:** Actinomyces species are not strictly anaerobic, as they can grow in the presence of oxygen, albeit poorly.
**Option B:** While Actinomycosis can present with a variety of symptoms, a chronic, indolent course is a hallmark of the disease.
**Option C:** Actinomycosis is indeed often associated with dental caries or oral trauma, which can provide a portal of entry for the bacteria.
**Option D:** Actinomycosis is usually treated with a course of antibiotics, typically penicillin or amoxicillin.
**Clinical Pearl / High-Yield Fact**
Actinomycosis is often misdiagnosed as a malignancy or tuberculosis due to its chronic and granulomatous nature. A high index of suspicion and awareness of the characteristic "sulfur granule"-containing discharge can aid in diagnosis.
**Correct Answer:** A. Actinomycosis is caused by a gram-positive, anaerobic bacterium.