Colonies of Stenotrophomonas maltophilia on Mueller-Hinton agar. Cultivation 72 hours, aerobic atmosphere, 28°C.
Stenotrophomonas maltophilia frequently colonizes breathing tubes such as endotracheal or tracheostomy tubes, the respiratory tract and indwelling urinary catheters. Infection is usually facilitated by the presence of prosthetic material (plastic or metal), and the most effective treatment is removal of the prosthetic material (usually a central venous catheter or similar device).
The growth of S. maltophilia in microbiological cultures of respiratory or urinary specimens is therefore sometimes difficult to interpret and not a proof of infection. If, however, it is grown from sites which would be normally sterile (e.g., blood),
then it usually represents true infection.
In immunocompetent individuals, S. maltophilia is a relatively unusual cause of pneumonia, urinary tract infection, or blood stream infection; in immunocompromised patients, however, S. maltophilia is a growing source of latent pulmonary infections. S. maltophilia colonization rates in individuals with cystic fibrosis have been increasing.