Actinomyces (Murray 3rd Ed pp 291)

These are facultatively anaerobic, gram +ve bacilli. Not acid fast, grow slowly in culture, are non-spore forming, and form filaments in specimens. Most important human disease causing organism is: A. israelii (human actinomycosis).

Pathogenesis & Immunity (Murray 3^rd pp 292)

Colonise the URT, GIT, and female GUT. Actinomycosis occurs when multiple abscesses are connected to one another by sinus tracts. ‘Sulphur granule’ colonies are seen (yellow/orange). Most cases are cervicofacial type, sometimes abscesses of lung due to aspiration (thorax type). Abdominal actinomycosis can also form, can spread to virtually every organ in the body via blood + lymphatics.

Treatment (Murray 3^rd Ed pp 294)

Surgical debridement of the tissue (i.e.: making it into a tidy wound), along with continuous administration of antibiotics. Most common usage is penicillin along with erythromycin & tetracyclines.

Category: Microbiology Notes