This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Surgery
Actinomycosis is caused by 
Select and explain. 
A. Gram +ve filamentous Bacteria, B. Gram –ve filamentous bacteria, C. Fungi, D. None of the above
A: Gram +ve filamentous Bacteria
Answer: A: Gram +ve filamentous Bacteria 
Explanation: Actinomycosis is caused by Actinomyces israeli,, an anaerobic gram positive filamentous organism.
Microscopy reveals characteristic sulphur granules in the pus.
The four clinical forms of actinomycosis are cervico-facial (commonest), ileocaecal, thoracic and in liver.
Penicillin is the drug of choice in treating actinomycosis.