Stenotrophomonas Maltophilia Clinical Presentation

Updated: Sep 16, 2021
  • Author: Sara Ahmed, MBBS, FCPS, MRCP(UK); Chief Editor: Michael Stuart Bronze, MD  more...
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Because S maltophilia infections are extremely uncommon, no specific patient history suggests its presence other than contact with other colonized individuals.

Obtaining a history of the use of irrigant solutions that could potentially contain S maltophilia is important in an epidemiological setting rather than in a clinical setting.

Patients often have a history of indwelling catheters, use of immunosuppressant therapy or broad-spectrum antibiotics, or cystic fibrosis.



Signs and symptoms of S maltophilia infections are related to the organ system involved and are indistinguishable from infections with other pathogens.



S maltophilia is a nonfermentative aerobic gram-negative bacillus formerly classified in the genus Pseudomonas. Unlike Pseudomonas aeruginosa, S maltophilia is an organism of low virulence with limited ability to cause infection in humans.

S maltophilia is a water organism, and it survives and multiplies in aqueous environments, particularly respiratory secretions, urine, intravenous fluids, and irrigant solutions.

S maltophilia may persist in an aquatic environment for extended periods.

Sources of S maltophilia colonization include the following:

  • Personnel
    • Hands
    • Antiseptic soaps
    • Hand lotion
  • Respiratory equipment and/or fluids
    • Ultrasonic nebulizers
    • Inhalation medications
    • Respirator tubing condensate
  • Intravenous lines and/or fluids
    • Intravenous solutions
    • Central venous catheters
  • Pressure monitoring devices - Pressure transducer fluids
  • Dialysis machines [16]
  • Urine and/or fluids
    • Indwelling Foley catheters
    • Urometers
    • Irrigation solutions
    • Hospital tap water [1]
    • In a Greek multicenter study on the colonization of municipal water supplies, treated water, and dialysate, S maltophilia accounted for 13.5% of isolates, Pseudomonas for 22.7%, and Chryseobacterium for 14.9%. [17]