A microbiologist is reading the plates from a sputum culture. On the sheep blood agar (SBA), the microbiologist sees flat spreading colonies with a metallic sheen. On cetrimide agar, a fluorescent green color is seen in the medium with clear colonies. On MacConkey, medium clear colonies are seen that have a fruity or grapelike odor. What is the most likely organism?
A) Pseudomonas fluorescens
B) P. aeruginosa
C) P. putida
D) P. stutzeri

Question

Quizplus · Accepted Answer

The metallic sheen seen on SBA and fluorescent green color seen on cetrimide agar are characteristic of Pseudomonas aeruginosa. The fruity or grapelike odor seen on MacConkey agar is also consistent with P. aeruginosa, which is known to produce a fruity odor. P. fluorescens and P. putida may also produce a metallic sheen on SBA, but neither typically fluoresces on cetrimide agar. P. stutzeri may produce a metallic sheen on SBA, but it does not typically fluoresce on cetrimide agar and does not produce a fruity odor on MacConkey agar.

A Microbiologist Is Reading the Plates from a Sputum Culture