Actinomyces israelii

A. israelii is anerobic, slow-growing, and has low virulence. Opportunistic pathogen: – It is a common colonizer of the oral cavity and upper respiratory tract, and is sometimes present in the gastrointestinal and urogenital tracts. Branching, fungus-like morphology. Colonies, aka, sulfur granules: – Granules comprise bacteria and calcium phosphate, and have a dimpled, molar-like appearance. – They do not contain sulfur. Most A. israelii infections occur when the bacteria invade deeper tissues of the oral cavity after trauma or surgery. From there, infections can spread. Chronic, slow forming granulomatous lesions that become abscesses that drain pus with sulfur granules. Infection most commonly occurs in the cervicofacial region following dental trauma. – Produces localized swelling, often in the mandibular region: "lumpy jaw." – The abscess may form sinus tracts that erupt on the face. When infection occurs in other sites, more serious complications can arise: – Central nervous system infection can manifest as a single abscess with headache and focal neurological signs. In the image of an abscess removed from the brain, we see examples of "dust bunny" formation; this reflects aggregation of the filamentous bacteria. – Thoracic infection typically produces nonspecific symptoms such as fever and non-productive cough, and lung abscesses may form. – Abdominal cavity infection can affect any organ, and can produce fever and fatigue. Be aware that digestion problems and inflammation may be mistaken for signs of Crohn's diseases, and masses have been mistaken for tuberculosis and cancerous tumors. Abdominal cavity infection can affect any organ, and can produce fever and fatigue. – Pelvic actinomycosis has been associated with long-term use of intra-uterine devices; masses can easily be mistaken for tumors. Prevention of actinomyces includes good oral hygiene, and, in the case of dental procedures, prophylactic antibiotics. Treatment includes drainage or surgical debridement when necessary and administration of penicillin.