Sketchy Micro: Actinomyces

Question 1

What kind of bacteria is Actinomyces israelii?

Answer 1

Gram-positive, filamentous (branching) rod

(Think of the tree behind the Israeli soldier with prominent branches and the violet jaw wrapping that is around the soldier’s head.)

Question 2

What is the soldier sitting next to (and how can this help you remember something about Actinomyces israelii)?

Answer 2

He’s sitting next to a gas mask, which is the Sketchy symbol for a bacteria that is an obligate anaerobe.

Question 3

Actinomyces normally colonizes the ____________, so _________ trauma can often lead to Actinomyces infection.

Answer 3

oral cavity; jaw

• Note: because of this, USMLE questions will often include a history of dental work to clue you in to Actinomyces infection.

(Think of the soldier’s jaw wrapped in that violet bandage.)

Question 4

What physical signs can A. israelii cause?

Answer 4

Sinus tracts, which are holes from the sinuses to the oral cavity or skin, that drain yellow sulfur granules.

(Think of the storm drain behind the soldier and all the yellow rocks throughout the desert.)

Question 5

What drug treats infections with A. israelii?

Answer 5

Penicillin G (like the pencil in the soldier’s hand)