Stenotrophomonas maltophilia

S. maltophilia frequently colonizes humid surfaces such as the tubes used in mechanical ventilation and indwelling urinary catheters, as well as medical devices such as suction catheters and endoscopes.^[2] Infection is usually facilitated by the presence of prosthetic material (plastic or metal), and the most effective treatment is removal of the prosthetic material (usually a central venous catheter or similar device). S. maltophilia adheres strongly and forms biofilm on plastic surfaces although these abilities may vary greatly between strains. Hydrophobicity was correlated to successful adhesion and biofilm formation on polystyrene surfaces.^[7] S. maltophilia frequently co-occurs and forms multispecies biofilms with Pseudomonas aeruginosa. S. maltophilia substantially influences the architecture of P. aeruginosa structures, causing development of extended filaments. These changes arise due to diffusible signalling factor encoded by S. maltophilia.^[8][9]

The growth of S. maltophilia in microbiological cultures of respiratory or urinary specimens is difficult to interpret due to its low pathogenicity, and is not proof of infection.^[2] If, however, it is grown from sites which would be normally sterile (e.g., blood), then it usually represents true infection. S. maltophilia can be found in the flora of captive snakes.^[10]

In immunocompetent individuals, S. maltophilia is a relatively unusual cause of

S. maltophilia is naturally resistant to many broad-spectrum antibiotics (including all carbapenems) due to the production of two inducible chromosomal metallo-β-lactamases (designated L1 and L2).^[3][14] This makes treatment of infected patients very difficult. S. maltophilia is ubiquitously present in the environment and impossible to eradicate, which makes prevention also extremely difficult.

Sensitivity testing requires nonstandard culture techniques (incubation at 30 °C).^[15][16] Testing at the wrong temperature results in isolates being incorrectly reported as being susceptible when they are, in fact, resistant. Disc diffusion methods should not be used, as they are unreliable, and agar dilution should be used instead.^[17][18]

S. maltophilia is not a virulent organism and removal of the infected prosthesis is frequently sufficient to cure the infection; antibiotics are only required if the prosthesis cannot be removed. Many strains of S. maltophilia are

Stenotrophomonas maltophilia has had multiple different names in the past. It was first found in a pleural effusion in 1943 and given the name Bacterium bookeri. It was then renamed to Pseudomonas maltophilia in 1961. It was moved to the genus Xanthomonas in 1983, and most recently to Stenotrophomonas in 1993.^[2]

References