Language
Country/Area
No result found
A mystery of survival on a medical device: Why is Stenotrophomonas maltophilia so good at thriving in humid environments?
The bacterium Stenotrophomonas maltophilia is of increasing concern in healthcare settings. This anaerobic, nonfermenting, Gram-negative bacterium, although uncommon, can cause difficult-to-treat infections in humans. Since its first discovery in 1943, S. maltophilia has gone through many twists and turns in its naming, and was finally classified as a core species in the genus Stenotrophomonas in 1993.
S. maltophilia is a bacterium commonly found in aquatic environments, soil and plants that thrives in moist environments, making the situation worse.
The bacteria finds home on medical device surfaces, and its compatibility with mechanical ventilators, inserted urinary catheters, etc., makes it a significant risk to hospitalized patients. Prosthetic limbs and catheters, whether plastic or metal, create ideal conditions for their reproduction. The strong adhesion ability of S. maltophilia and its ability to form biofilms complicate its prevention in healthcare settings.
Pathogenic mechanism
S. maltophilia often colonizes moist surfaces, such as mechanical ventilation lines and inserted urinary catheters. In these environments, infection often occurs in the presence of prosthetic materials, and removal of the prosthetic device is the most effective treatment. treatment methods. Different strains have quite different abilities for attachment and biofilm formation, and there is a clear correlation between their hydrophobicity and successful attachment and biofilm formation.
S. maltophilia coexists with other bacteria such as Pseudomonas aeruginosa to form multispecies biofilms, which further affect their growth and structure.
When S. maltophilia grows in normally sterile sites (such as the blood), it usually represents a true infection, whereas in immunocompetent individuals, it is relatively less pathogenic. This strain is a potential source of lung infection in immunocompromised individuals, and colonization rates are increasing in patients with cystic fibrosis. The outer membrane vesicles (OMVs) released by this bacterium cause a significant inflammatory response and stimulate the body to release pro-inflammatory cytokines.
Treatment Challenges
Because S. maltophilia is naturally resistant to many broad-spectrum antibiotics, including all carbapenems, treating infected patients is difficult. The bacteria's ubiquity in the environment makes its elimination almost impossible and preventive measures difficult to implement. Appropriate susceptibility testing requires nonstandard culture techniques, which, if not performed properly, can lead to misreporting of sensitivities.
Many strains of S. maltophilia remain susceptible to drugs such as flupentixol and isoflurane, but resistance is increasing.
Ideally, the infected prosthesis should be removed from the limb; if this is not possible, antibiotics should be used as an adjunct to treatment. Many strains are susceptible to piperacillin and ceftazidime, while tetracyclines such as tigecycline have also shown efficacy. Although adhesions can sometimes be inconvenient, the infection can improve with proper treatment.
Epidemic and risk factors
In severely immunocompromised individuals, infection with Stenotrophomonas is relatively lethal. Risk factors include HIV infection, malignancy, cystic fibrosis, mechanical ventilation, and use of a central venous catheter. In addition, the infections caused are also closely related to long-term hospitalization, intensive care unit treatment and extensive use of antibiotics.
History of Bacteria
Since its first discovery in 1943, S. maltophilia has undergone several name changes, from Bacterium bookeri to Pseudomonas maltophilia, and has been identified as part of the genus Stenotrophomonas at various levels of classification, indicating its importance to the scientific community and This highlights the need for continued research into the properties of this bacterium.
The presence and proliferation of S. maltophilia in healthcare facilities represents a problem that cannot be ignored, especially in humid environments. Is this due to the adaptability of bacteria or poor management of the medical environment?
