Actinomycosis is a chronic or slowly progressive infection that is caused by different bacterial species of the actinomyces genus, most commonly species is known to be actinomyces israelii.
Actinomyces are normal inhabitants of the mouth, gastrointestinal tract, and female genital tract, and do not cause an infection unless there is a break in the skin or mucosa. Actinomyces also seem to require the presence of other accompanying bacteria in order to cause disease.
The disease is characterized by the formation of an abscess and draining sinus tracts (small tunnels which open onto the surface of the skin or mucous membranes and drain pus). The draining pus contains yellow granules called sulphur granules. These are named from the color of the granules, not their content.
Actinomycosis is to be differentiated from actinomycetoma, which is a chronic infection of the skin and subcutaneous tissue, usually involving the foot.
Actinomycetoma is caused by various species of actinomyces that are present in soil and plant material in tropical regions.
Who is at risk of actinomycosis?
Actinomycosis is relatively rare, but the following factors increase the risk of infection:
- Poor oral hygiene that is followed by dental surgery or trauma
- Impaired immunity e.g. immunosuppressive medications or chronic conditions like diabetes mellitus
- Residence in tropical countries
How is actinomycosis diagnosed?
- Material that is obtained from aspirating an abscess or sinus tract is cultured in the laboratory for further use strict growth conditions are required to grow actinomyces. Often, a variety of accompanying bacteria will be present.
- Sulphur granules can be checked under a microscope to look for characteristic features of actinomyces however this is not a conclusive test, as another bacterium called nocardia has a similar appearance.
What is the treatment for actinomycosis?
The goal of actinomycosis treatment is to treat the infection with large doses of antibiotics and surgery to create unfavorable aerobic conditions for the growth of actinomyces species.
- Actinomycosis is treated with antibiotics, like penicillin. Intravenous penicillin should be given in high doses after oral penicillin, as it is generally needed to penetrate areas of fibrosis and suppuration. Prolonged treatment is often required to prevent relapse.
- Alternative antibiotics include tetracyclines, erythromycin, and clindamycin.
- The surgical management of the disease involves drainage of deep abscesses, cutting of sinus tracts and extraction of bulky infected masses.
- The combination treatment involving penicillin and surgery mostly produces a cure