Stenotrophomonas maltophilia


Stenotrophomonas maltophilia is an environmental global emerging Gram-negative MDRO that is most commonly associated with respiratory infections in humans

  • high fatality/case ratio
  • transmitted by healthcare workers and by direct contact with source
  • primarily a hospital acquired infection, though community acquire infections are increasing


  • Gram-negative obligate aerobic motile bacillus with a few polar flagella
  • able to persist in nutrient-poor aqueous environments, including plant rhizospheres, animals, foods, water sources and in-hospital sites (e.g. tap water, sink drains, soap, medical devices and prostheses)
  • adheres to plastics and forms biofilms
  • low virulence, primarily affects the immunocompromised
  • intrinsically resistant to antibiotics due to:
    — low membrane permeability
    — presence of chromosomally encoded multidrug resistance efflux pumps, β-lactamases and antibiotic-modifying enzymes


For infection

  • immunocompromise
  • cystic fibrosis
  • ECMO
  • RRT
  • prolonged ICU stay
  • malignancy
  • prior antibiotic use
  • indwelling devices (e.g. IDCs, CVCs, ICCs)

For mortality

  • LOS in ICU
  • CVC present
  • mechanical ventilation
  • malignancy inappropriate antibiotics
  • shock
  • thrombocytopenia


  • most commonly respiratory tract infection
  • can cause infection of nearly any organ or tissue, e.g. endocarditis, osteomyelitis, meningitis, biliary sepsis, septicaemia, central line associated infection, eye infections, soft tissue and skin infections


Difficult to distinguish between colonisation and infection in many instances

  • swabs and tissue samples MCS
  • PCR


  • infection control measures
  • do not treat colonisation with antibiotics, only infection
  • source control
  • antibiotics
    — co-trimoxazole (first line)
    — other options: minocycline, moxifoxacin, colistin/polymyxin B, cefepime, tigecycline, combination therapy
    — resistant to: aminoglycosides, antipseudomonal penicillins, and antipseudomonal third-generation cephalosporins
  • supportive care and monitoring
  • consult infectious diseases specialist

References and Links

Journal articles

  • Brooke JS. Stenotrophomonas maltophilia: an emerging global opportunistic pathogen. Clin Microbiol Rev. 2012 Jan;25(1):2-41. PMC3255966.
  • Looney WJ, Narita M, Mühlemann K. Stenotrophomonas maltophilia: an emerging opportunist human pathogen. Lancet Infect Dis. 2009 May;9(5):312-23. PMID: 19393961.

CCC 700 6

Critical Care


Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.

After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.

He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE.  He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.

His one great achievement is being the father of three amazing children.

On Twitter, he is @precordialthump.

| INTENSIVE | RAGE | Resuscitology | SMACC

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