Which characteristic differentiates Pseudomonas aeruginosa from Pseudomonas putida?

Which characteristic differentiates Pseudomonas aeruginosa from Pseudomonas putida?

• A. Growth at 42°C positive for P. aeruginosa
• B. Oxidase positivity
• C. Pigment production
• D. Growth on MAC

Answer: (A)

The key point is temperature tolerance. Pseudomonas aeruginosa can grow at elevated temperatures, including 42°C, whereas Pseudomonas putida does not grow at that temperature. This difference in growth at 42°C is a useful clinical differentiator between the two species. Other traits like oxidase positivity, pigment production, or growth on MAC are not reliable distinguishing features here because both organisms are oxidase-positive, can grow on MacConkey as non-lactose fermenters, and pigment production varies. Thus, growth at 42°C is the best differentiating characteristic.

The key point is temperature tolerance. Pseudomonas aeruginosa can grow at elevated temperatures, including 42°C, whereas Pseudomonas putida does not grow at that temperature. This difference in growth at 42°C is a useful clinical differentiator between the two species. Other traits like oxidase positivity, pigment production, or growth on MAC are not reliable distinguishing features here because both organisms are oxidase-positive, can grow on MacConkey as non-lactose fermenters, and pigment production varies. Thus, growth at 42°C is the best differentiating characteristic.