3.3.EX Lab diag (Gram positive bacilli)

Question 1

Cellular morphology:
Gram +
Branching filamentous rods

Colonial morphology:
White
Opaque
“Molar tooth” resemblance

Answer 1

Actinomyces israelii

Question 2

Cellular Morphology:
Diphtheroid
End of the cell may be pointed (Fusiform), bent, club shaped, spatulated, etc.

“Dog bones”
“Starlike aggregates”
“V or Y arrangements / Palisade”

Colonial appearance:
Small
Cream-white
Convex
Shiny with irregular edge

Answer 2

Bifidobacterium spp.

Question 3

48 hr colony <1mm (+)
Rough colony (+)
Branched bacilli (+)
Catalase (-)
Indole (-)

Molar tooth colony

Answer 3

Actinomyces israelii

Question 4

48 hr colony <1mm (-)
Rough colony (-)
Branched bacilli (-)
Catalase (-)
Indole (-)

Rod w/ forked ends

Answer 4

Bifidobacterium spp.

Question 5

48 hr colony <1mm (-)
Rough colony (-)
Branched bacilli (-)
Catalase (+)
Indole (+)

Answer 5

Propionibacterium acnes