Introduction to Stenotrophomonas maltophilia

This step will focus on Stenotrophomonas maltophilia, as this Stenotrophomonas species causes the greatest number of infections – with serious implications for vulnerable patients.

S. maltophilia can be found in soil, water and plants, and mainly affects those who are immunocompromised and based in the hospital (including the ICU); infection in those without compromised immune systems is rare. Those most at risk to infection are patients who have had prior exposure to antimicrobials (particularly broad-spectrum antibiotics), those on ventilators, and patients with prolonged hospitalisation.

S. maltophilia infections

Unlike Acinetobacter spp., this pathogen does not tend to spread between patients and is usually acquired from environmental sources. Some associated infections include:

• Bacteraemia (bacterial blood stream infections) – with high patient mortality rates

• Endocarditis

• Pneumonia

• Osteomyelitis

• Meningitis

• Soft tissue and skin infections

Management of infections caused by S. maltophilia

S. maltophilia shows intrinsic resistance to cephalosporins, carbapenems, and aminoglycosides. This can limit the treatment options for infections caused by the bacterium, but many clinical isolates are not resistant to co-trimoxazole – meaning this is often used in treatment of these infections.