This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Stenotrophomonas maltophilia (S. maltophilia) infection is a type of bacterial infection. S. maltophilia is found mostly in wet environments. In the hospital setting, S. maltophilia can be found in fluids, such as irrigation solutions (fluids used to clean a wound or wash out a body cavity like the ear canal or bladder) and intravenous (IV) fluids, as well as patient secretions, such as mucus from the respiratory tract and urine. The bacteria causes problems mainly in people who have a weakened immune system. To cause infections in healthy people, S maltophilia must bypass the normal human defenses, as can happen with the use of certain medical devices, such as catheters or IV lines. People who are hospitalized and receiving treatment for other serious medical conditions may be more susceptible to an infection, especially if their immune system is weakened. Symptoms vary depending on the area of the body infected.
Diagnosis of S. maltophilia infection, along with other bacterial infections, may be suspected by symptoms and risk factors. A culture of body fluids, such a blood, urine, sputum, or abdominal fluid, is used to confirm the specific type of bacteria. A consultation with an infectious disease specialist is important to differentiate bacterial colonization (where the bacteria are found in the body but do not cause symptoms) from an infection and to determine the best treatment options. 
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