| • | gram (+) rods (filamentous); anaerobes; part of normal flora of mouth and GI tract  |  
 | • | are bacteria (prokaryotes) but act like fungi:  grow in the form of mycelia and are water and soil saprophytes |  
 | • | causes eroding abscesses following trauma to the mucous membranes of the mouth or GI tract  |  
 | • | the infection is named according to the area of the body through which the abscess erodes:   |  
 | • | cervicofacial actinomycosis (hard nodule – “lumpy jaw”) |  
 | • | abdominal actinomycosis (Bacteroides fragilis is also a GI tract resident that forms abscesses following trauma, but it rarely resides in the mouth) |  
 | • | sulfur granule = yellow granules  (microcolonies of Actinomyces) seen under the microscope when examining the draining pus |  
  
 |