Question

"A technician is reading the plates from a sputum culture. On the sheep blood agar (SBA), she sees flat spreading colonies with a metallic sheen. On cetrimide agar, she sees a fluorescent green color in the media with clear colonies. On MacConkey, she sees medium clear colonies that have a "fruity or grape-like odor." What is the most likely organism?"

Answer 1

Answer:

P. aeruginosa

Explanation:

P. aeruginosa is a gram-negative bacteria that belongs to the family Pseudomonadaceae.

From the given question the following points lead us to conclude that the colony that will be growing would be of P. aeruginosa :

1. Flat spreading colonies with a metallic sheen on SBA - P. aeruginosa is known to produce smooth colonies with flat edges.

2. Fluorescent green color in the media with clear colonies on cetrimide agar - P. aeruginosa is known to produce pyoverdin which is a fluorescent pigment under low iron conditions.

3. Medium clear colonies that have a "fruity or grape-like odor" on MacConkey Agar - P. aeruginosa has a sweet fruity odor which is its characteristic odor because of the production of trimethylamine.

Thus, from all these characteristics one can conclude that the organism in the culture is P. aeruginosa.