Which bacterium causes green discoloration and a fruity odor in some infected wounds?

Pseudomonas aeruginosa can cause green discoloration and a fruity odor in some infected wounds.

This Gram-negative, rod-shaped bacterium produces pigments including pyocyanin, which can give infected material a blue-green or green appearance. Its odor is sometimes described as sweet or fruity. These clues are suggestive rather than sufficient for diagnosis, because wound appearance can vary and laboratory testing is required to identify the organism reliably.

P. aeruginosa is common in soil and water and can survive in moist hospital environments. It is an opportunistic pathogen: healthy people are often unaffected, while people with burns, cystic fibrosis, weakened immunity, or invasive medical devices face greater risk. It can cause pneumonia, bloodstream infection, urinary infection, and other diseases.

The bacterium is difficult to treat because it has low outer-membrane permeability, drug-efflux systems, and the ability to form biofilms. Green wound drainage is therefore not proof of Pseudomonas, and it should not replace professional evaluation or culture-based testing.