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Disease Profile

Stenotrophomonas maltophilia infection

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


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Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Stenotrophomonas maltophilia; S. maltophilia infection; S. maltophilia


Bacterial infections


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.[1][2][3] 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.[1][2]

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. [1][2]


Symptoms of Stenotrophomonas maltophilia (S. maltophilia) infection depend on which area of the body or organ system is infected. The most common sites of infection are the lungs and blood.[1][2] When the lungs are infected, symptoms of S. maltophilia are similar to other bacterial pneumonia and may include fever, cough, mucus, shortness of breath, and chest pain.[4] Symptoms of a blood infection (bacteremia) may include a fever, rapid heart rate, low blood pressure, abdominal pain, nausea, vomiting, diarrhea, and confusion.[5]

Less commonly, people infected by S. maltophilia experience infections of the heart (endocarditis), the bone behind the ear (mastoiditis), lining of the abdomen and internal organs (peritonitis), cerebral spinal fluid (meningitis), soft tissue, wounds, urinary tract, and/or eye.[2][3] The symptoms are similar to other bacterial infections of the same sites. An infection can also cause skin symptoms or complications such as cellulitis, infected ulcers, and ecthyma gangrenosum.[2]


Stenotrophomonas maltophilia (S. maltophilia) infections are caused by the S. maltophilia bacteria. These bacteria live in wet environments. In a hospital setting, they are able to survive and multiply in fluids such as mucus of the respiratory system, urine, intravenous (IV) fluids, and irrigation fluids used to clean wounds or body cavities such as the ear canal or bladder. S. maltophilia can also grow in medical devices exposed to these fluids including urinary catheters, IV lines, and breathing machines (ventilators).[1][2][3]

Most healthy people do not get S. maltophilia infections even when exposed to the bacteria. However, 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. Factors that increase the risk for S. maltophilia infection include admission to an intensive care unit (ICU), prolonged hospitalization, HIV infection, cancer, cystic fibrosis, neutropenia, recent surgery, serious trauma or injury, being on a breathing machine (ventilator), and previous treatment with broad-spectrum antibiotics (medications that target a wide range of bacteria).[1][2][3]


Stenotrophomonas maltophilia (S. maltophilia) infection is usually suspected when there are symptoms of a bacterial infection along with certain risk factors. A small sample of body fluid such as blood, mucus, urine, or abdominal fluid will be cultured to confirm which bacteria is causing the infection.[1] When an infection is suspected, other possible sites of infection including wounds, intravenous (IV) catheters, urinary catheters, and breathing machines should also be tested for the presence of the bacteria.[1][3] 

Because S. maltophilia may sometimes grow in parts of the respiratory system or other parts of the body without causing infection (colonization), an infectious disease specialist should be consulted to determine if there is a true infection.[2]


Stenotrophomonas maltophilia (S. maltophilia) bacteria are resistant to many antibiotics, so treatment options may be limited. As of 2018, treatment usually begins with trimethoprim-sulfamethoxazole (also called co-trimoxazole, or TMP-SMX), but this may vary due to the antibiotic resistance of the particular strain causing the infection and/or new antibiotics being developed. Potential alternatives for people unable to tolerate TMP-SMX include a class of antibiotics called fluoroquinolones, in particular, levofloxacinMinocycline and tigecycline have also been shown to be effective in small retrospective studies. Combination therapy (using more than one antibiotic) may be necessary in life-threatening cases. However, data regarding the benefit of combination therapy are currently limited, so its role remains uncertain.[2][3] 

The duration of therapy often depends on the site of infection.[1][2] A longer duration of therapy may be necessary for people with a weakened immune system.[2] Consultation with an infectious disease specialist is important to develop an individualized treatment plan.[1][2] 

More detailed information about medications used to treat S. maltophilia infection is available from Medscape Reference.


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Learn more

    These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

    In-Depth Information

    • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
    • PubMed is a searchable database of medical literature and lists journal articles that discuss Stenotrophomonas maltophilia infection. Click on the link to view a sample search on this topic.

      Selected Full-Text Journal Articles


        1. Cunha BA. Stenotrophomonas Maltophilia. Medscape Reference. May 22, 2017; https://emedicine.medscape.com/article/237024-overview.
        2. Lewis SS, Zaas A. Stenotrophomonas maltophilia. UpToDate. May 30, 2018; https://www.uptodate.com/contents/stenotrophomonas-maltophilia.
        3. Brooke JS. Stenotrophomonas maltophilia: an Emerging Global Opportunistic Pathogen. Clin Microbiol Rev. January, 2012; 25(1):2-41. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3255966/.
        4. Pneumonia. MedlinePlus. August 8, 2018; https://medlineplus.gov/pneumonia.html.
        5. Tunkel AR. Bacteremia. Merck Manual Professional Version. May 2016; https://www.merckmanuals.com/professional/infectious-diseases/biology-of-infectious-disease/bacteremia.

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