Many different species are present, and taxonomy continues to change; some species previously known as Actinomyces have been reclassified in other genera, such as Arcanobacterium spp and Trueperella spp. Regardless, disease aspects remain unchanged. Commonly found as part of the oral, GI, and genital microbiotas,1-3 Actinomyces spp and related genera are of limited virulence unless inoculated into tissue (eg, via bites, foreign bodies, or trauma).
- Four main types of infection can be encountered: cervicofacial, thoracic, abdominal, and subcutaneous.4-9
- Clinical signs correspond to the tissues involved and the severity of disease.
- Disease is often associated with firm and fibrous masses, persistent exudates (eg, pyothorax7,10), draining tracts, abscessation, and osteomyelitis.