Actinomycosis

Actinomycosis is a rare, pyogenic granulomatous, subacute to chronic infection caused by actinomycetes. Actinomycetes are a group of anaerobic gram-positive bacteria with high guanine-cytosine content found as natural flora of the oral cavity.

The most frequent features are ulcer and granuloma formation, and the presence of multiple abscesses and sinus tracts that may discharge sulfur granules. The pathogens often spread into neighboring tissues.

Actinomycetes often invade the body by microfissures, and the most common clinical form of actinomycosis is cervicofacial, either after oral surgery or caused by poor dental hygiene. Thoracic and abdominal actinomycoses also occur frequently, and pelvic actinomycosis is possible in women.

Prolonged antibiotic treatment is necessary.

Actinomycosis is an infectious disease caused by anaerobic, gram-positive actinomycetes. The most common clinical forms of actinomycosis are cervicofacial and abdominal.[1]Smego RA Jr, Foglia G. Actinomycosis. Clin Infect Dis. 1998 Jun;26(6):1255-61. http://www.ncbi.nlm.nih.gov/pubmed/9636842?tool=bestpractice.com In women, pelvic actinomycosis is possible.[2]Taga S. Diagnosis and therapy of pelvic actinomycosis. J Obstet Gynaecol Res. 2007 Dec;33(6):882-5. http://www.ncbi.nlm.nih.gov/pubmed/18001459?tool=bestpractice.com Many other sites of infection have been described, although less frequently than cervicofacial and abdominal actinomycoses. Because the disease is rare and most physicians have not seen a patient with actinomycosis, diagnosis is often delayed.

Whipple disease, which may be interpreted as a special form of actinomycosis because it is caused by Tropheryma whipplei, a pathogen from the clade of actinomycetes, is not discussed here. See Whipple’s disease.