The actinomycete are anaerobic or microaerophilic, nonspore-forming, Gram-positive, branching bacteria that colonize the mouth, colon and female genital tract. Six of the 13 Actinomyces species have been associated with human disease; of those, Actinomyces israelii is the most frequently isolated. The most common site of actinomycotic infection is the cervicofacial area, but pulmonary and hepatic abscesses are also encountered. Due to the fastidious nature of this organism, the culturing of Actinomyces species can be difficult, and the diagnosis is often based solely on the characteristic microscopic pathology (filamentous, branching and often beaded Gram-positive rods). Nocardia species have a similar appearance when Gram stained; however, they can be differentiated from the actino-mycete by a positive modified acid-fast stain.
The diagnosis of actinomycosis is often delayed, probably because of its subacute presentation. The presence of sulfur granules in exudates is strongly supportive of the diagnosis of actinomycosis; however, sulfur granules are less often detected when the specimens are retrieved via percutaneous aspirations. birth control pills
Actinomycosis of the liver represents 5% of all cases and 15% of those cases involving the abdomen. Infection is frequently cryptogenic (80.7%), presenting with fever (83.3%), abdominal pain (74.5%) and weight loss (50.9%) over a 3.7±5.1 month period.