A hospitalized adult developing pneumonia who produces green pigment is likely infected with which organism?

The presence of green pigment production in a patient with pneumonia strongly suggests infection with Pseudomonas aeruginosa. This organism is well-known for its distinctive green pigment due to the production of pyocyanin and other pigments, especially in clinical settings such as burns, respiratory infections, and in immunocompromised individuals. The green coloration is a key characteristic that helps in identifying this pathogen in laboratory cultures.

Pseudomonas aeruginosa is an opportunistic pathogen commonly associated with severe infections, particularly in hospitalized patients. It can cause pneumonia, especially in those who are ventilated or have underlying chronic lung diseases. The organism also has a versatile metabolic capability, which allows it to thrive in various environments, including hospital settings.

While other organisms listed may be involved in pneumonia, they do not produce the same green pigments as Pseudomonas aeruginosa. For instance, Klebsiella pneumoniae is known for causing pneumonia but typically appears mucoid rather than green. Serratia species can produce a red pigment, not green, and Proteus species can present with different coloration but are also not known for green pigment production. This distinctiveness of Pseudomonas aeruginosa in producing green pigment makes it the most likely cause of