A sputum sample from a patient shows a growth of a lavender-green pigment. Which organism is most likely?

The growth of a lavender-green pigment in a sputum sample is a characteristic feature associated with Stenotrophomonas maltophilia. This organism is known for producing a distinctive greenish or lavender pigment when cultured, particularly on certain media, which aids in its identification in clinical microbiology.

Stenotrophomonas maltophilia is an opportunistic pathogen often found in immunocompromised patients or those with underlying pulmonary conditions. The presence of this pigment is significant in a clinical setting, as it not only helps in identification but also indicates its potential role as a pathogen.

Other organisms listed, such as Pseudomonas aeruginosa, Burkholderia cepacia, and Acinetobacter baumannii, may present with various colors or no pigment at all but do not consistently exhibit the lavender-green hue associated specifically with Stenotrophomonas maltophilia. Therefore, the distinct pigment produced by Stenotrophomonas maltophilia plays a crucial role in its identification and indicates its presence in the sample.