Which test group best differentiates Acinetobacter baumannii from Pseudomonas aeruginosa?

The option that effectively differentiates Acinetobacter baumannii from Pseudomonas aeruginosa is the combination of oxidase, motility, and nitrate (NO3) reduction tests.

Acinetobacter baumannii is oxidase-negative, while Pseudomonas aeruginosa is oxidase-positive. This key difference allows clinicians and microbiologists to distinguish between the two organisms quickly.

Motility is another factor: Pseudomonas aeruginosa is motile due to its flagella, whereas Acinetobacter baumannii is generally non-motile. Testing for motility can help solidify the identification further.

Lastly, the ability to reduce nitrate is a distinguishing feature as well. Pseudomonas aeruginosa typically can reduce nitrate to nitrite or further, while Acinetobacter baumannii usually cannot. This combination of oxidase reaction, motility, and nitrate reduction provides a clear framework for differentiating these two clinically relevant pathogens.