General Information: Stenotrophomonas maltophilia R551-3 was isolated from the poplar Populus trichocarpa x deltoides cv. "Hoogvorst" and is the second most common endophytic bacteria in poplar. Endophytic bacteria have been shown to increase plant growth or health but providing growth factors or nutrients and in aiding the degradation of toxic compounds. This species is an uncommon but serious source of infection in patients with breathing tubes such as endotracheal or tracheostomy tubes, or with chronically indwelling urinary catheters. Although the organism can colonize the devices without causing an infection, under certain conditions it can cause pneumonia, urinary tract infections, or an infection of the blood. This organism can also cause infection in immunocompromised patients. It has resistance to many commonly used antibiotics and therefore is often difficult to eradicate. Most strains are resistant to co-trimoxazole.