40- Anaerobic, nonspore forming gram + rods

Question 1

Actionomyces- physiology and structure

Answer 1

• Actinomyces organisms are anaerobic, gram-positive rods. They grow slowly in culture, and they tend to produce chronic, slowly developing infections. They typically develop delicate filamentous forms or hyphae (resembling fungi) in clinical specimens or when isolated in culture. They lack mitochondria and a nuclear membrane, reproduce by fission, and are inhibited by penicillin but not antifungal antibiotics.

Question 2

What are the differences between Actinomyces and Nocardia?

Answer 2

• Actinomyces are not acid-fast but Nocardia is weakly acid-fast. The presence of aerial hypae are acid fastness are unique to Nocardia. Nocardia also causes bronchopulmonary disease in immunocompromised patients while actinomyces causes suppurative lesions.

Question 3

Actinomyces- disease

Answer 3

Actinomycosis

Question 4

Actinomyces- clinical Sx

Answer 4

Development of chronic granulomatous lesions that become suppurative and form abscesses connected by sinus tracts. Sulfur granules, resembling grains of sand, can be seen in the abscesses

Question 5

Actinomyces- lab tests

Answer 5

Anaerobic, gram positive rods. Grow slowly in culture. Colonies appear white and have a domed surface

Question 6

Actinomyces- epidemiology

Answer 6

Infections are endogenous and not contagious. Seen in patients with poor oral hygiene or have undergone an invasive dental procedure or oral trauma. Also seen in patients with a history of aspiration.

Question 7

Actinomyces- pathogenesis

Answer 7

Colonize the upper respiratory, gastrointestinal and female genital tracts. Only cause disease when the normal mucosal barriers are disrupted by trauma, surgery or infection