<prompt> Actinomycosis is caused byGram ve filamentous BacteriaGram ve filamentous bacteriaFungiNone of the above  <response>: 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. 