The pathogenesis of aerobic actinomycetes bacteria includes the process by which an organism causes infection and spreads throughout the body, leading to disease. The aerobic actinomycetes are thought to be opportunistic pathogens that may cause severe infections in immunocompromised or immunosuppressed individuals. Only a relatively few aerobic actinomycetes are associated with human disease.
- The portal of entry is usually through traumatic skin inoculation or through inhalation. (It is not directly transmitted from humans or from animals. Traumatic skin inoculation may occur via a foreign body, or via injury/kick by a contaminated animal hoof [eg, equine, bovine]). Hospital-acquired infections (HAIs) are possible if the patient becomes infected by contaminated medical equipment or post-surgical wound infection. Construction (involving extensive remodeling) may also be a source of environmental contamination.
- Replication of the bacteria may lead to dissemination to other parts of the body.
- Disease states or clinical presentations: cutaneous, pulmonary, or disseminated forms
- Superficial abscess, localized cellulitis
- Mycetoma involving swelling of subcutaneous tissues and formation of sinus tracts (usually in the extremities); forming pus; chronic/systemic and progressive infection
- Pulmonary infection: The actinomycetes (usually Nocardia) can cause pneumonia, lung abscesses, or cavitary lesions
- Spread within the thoracic cavity, dissemination
- Spread to the central nervous system (CNS)
4. CDC/Ajello. Image #14742. Seen from a posterior perspective, this patient had contracted a nocardiosis infection of his right upper arm, due to Gram-positive, Nocardia brasiliensis bacteria, which had manifested as a cellulitic inflammation known as an actinomycotic mycetoma. PHIL public domain. Created 1974. Accessed October 27, 2022. https://phil.cdc.gov/Details.aspx?pid=14742
