What is the best choice of test to differentiate Pseudomonas aeruginosa from Acinetobacter spp.?

The selection of oxidase, motility, and growth at 42°C as the best choice of tests to differentiate Pseudomonas aeruginosa from Acinetobacter species is based on specific characteristics that are unique to each organism.

Pseudomonas aeruginosa is oxidase-positive, meaning it produces the enzyme cytochrome c oxidase, which plays a critical role in cellular respiration. Conversely, Acinetobacter species are usually oxidase-negative. This oxidase reaction serves as a primary differentiating factor between these two genera.

Additionally, Pseudomonas aeruginosa is motile due to its polar flagella, making it capable of swimming and exhibiting a characteristic motile quality on solid media. Acinetobacter spp., in contrast, are typically non-motile, which further aids in their identification.

The ability to grow at 42°C is another critical factor, as Pseudomonas aeruginosa can thrive at this elevated temperature, whereas Acinetobacter species generally do not grow at temperatures above 37°C. This characteristic is particularly advantageous in differentiating between the two, especially in clinical microbiology settings where rapid identification is essential.

In summary, the combination of oxidase positivity, motility, and growth at