Abdominal actinomycosis is a chronic, indolent disease characterized by nonspecific symptoms such as fatigue, weight loss, fever, and abdominal pain. Actinomyces is a genus of fastidious, gram-positive, non-acid-fast, branching filamentous bacilli characterized by sulfur granules that is normally found in oral flora and inhabits the gastrointestinal (GI) tract. Actinomyces infections are relatively rare, however when present, they have the ability to invade multiple organs and disseminate throughout multiple body cavities. Factors that increase the risk of developing actinomycosis include poor oral hygiene, alcoholism, and preexisting dental disease. Intrauterine devices (IUDs) also increase the risk of developing pelvic actinomycosis. Over the past 10-20 years, actinomycosis is being diagnosed with increasing frequency and should be considered in the differential for patients presenting with indolent abdominal symptoms along with risk factors.


  • While still rare, the incidence of abdominal actinomycosis is increasing.
  • Abdominal actinomycosis presents with a chronic, indolent course of nonspecific symptoms similar to other, more common conditions and, should be considered in patients with indolent abdominal symptoms and risk factors including poor dental hygiene, dental disease, and alcoholism.
  • The diagnosis is based on abscess fluid culture growing Actinomyces.
  • Treatment of actinomycosis is generally with a long course of IV Penicillin G later transitioned to oral Amoxicillin.