Stenotrophomonas maltophilia

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Stenotrophomonas maltophilia
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Gammaproteobacteria
Order: Xanthomonadales
Family: Xanthomonadaceae
Genus: Stenotrophomonas
Species: S. maltophilia
Binomial name
Stenotrophomonas maltophilia
Palleroni & Bradbury 1993
Synonyms

Pseudomonas maltophilia (ex Hugh and Ryschenkow 1961) Hugh 1981
Xanthomonas maltophilia (Hugh 1981) Swings et al. 1983
Pseudomonas hibiscicola Moniz 1963
Pseudomonas beteli corrig. (Ragunathan 1928) Savulescu 1947

Stenotrophomonas maltophilia is an aerobic, nonfermentative, Gram-negative bacterium. It is an uncommon bacterium and human infection is difficult to treat.[1] Initially classified as Pseudomonas maltophilia, S. maltophilia was also grouped in the genus Xanthomonas before eventually becoming the type species of the genus Stenotrophomonas in 1993.[2][3]

S. maltophilia is slightly smaller (0.7–1.8 × 0.4–0.7 micrometers) than other members of the genus. They are motile due to polar flagella, and grow well on MacConkey agar producing pigmented colonies. S. maltophilia is catalase-positive, oxidase-negative (which distinguishes it from most other members of the genus) and has a positive reaction for extracellular DNase.

S. maltophilia is ubiquitous in aqueous environments, soil, and plants; it has also been used in biotechnology applications.[4] In immunocompromised patients, S. maltophilia can lead to nosocomial infections.

Pathogenesis[edit]

S. maltophilia frequently colonizes breathing tubes such as endotracheal or tracheostomy tubes, the respiratory tract and indwelling urinary catheters. 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). The growth of S. maltophilia in microbiological cultures of respiratory or urinary specimens is therefore sometimes difficult to interpret and not a proof of infection. If, however, it is grown from sites which would be normally sterile (e.g., blood), then it usually represents true infection.

In immunocompetent individuals, S. maltophilia is a relatively unusual cause of pneumonia, urinary tract infection, or blood stream infection; in immunocompromised patients, however, S. maltophilia is a growing source of latent pulmonary infections.[5] S. maltophilia colonization rates in individuals with cystic fibrosis have been increasing.[6]

Treatment[edit]

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).[7] 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).[8][9] 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.[10][11]

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 sensitive to co-trimoxazole and ticarcillin, though resistance has been increasing.[12] It is not usually susceptible to piperacillin, and susceptibility to ceftazidime is variable.[citation needed] Tigecycline is also an effective drug. Polymyxin B may be effective treatment, at least in vitro, though not without frequent adverse effects.

Epidemiology[edit]

Stenotrophomonas infections have been associated with high morbidity and mortality in severely immunocompromised and debilitated individuals. Risk factors associated with Stenotrophomonas infection include HIV infection, malignancy, cystic fibrosis, neutropenia, mechanical ventilation, central venous catheters, recent surgery, trauma, and broad-spectrum antibiotic use.[13][14][15]

References[edit]

  1. ^ Gilligan PH, Lum G, VanDamme PAR, Whittier S (2003). Burkholderia, Stenotrophomonas, Ralstonia, Brevundimonas, Comamonas, Delftia, Pandoraea, and Acidivorax. In: Manual of Clinical Microbiology (Murray PR, Baron EJ, Jorgensen JH et al., Eds) (8th ed.). ASM Press, Washington, DC. pp. 729–748. ISBN 1-55581-255-4. 
  2. ^ Denton M, Kerr K (1 January 1998). "Microbiological and clinical aspects of infection associated with Stenotrophomonas maltophilia". Clin Microbiol Rev 11 (1): 57–80. PMC 121376. PMID 9457429. 
  3. ^ Palleroni N, Bradbury J (1993). "Stenotrophomonas, a new bacterial genus for Xanthomonas maltophilia (Hugh 1980) Swings et al. 1983". Int J Syst Bacteriol 43 (3): 606–9. doi:10.1099/00207713-43-3-606. PMID 8347518. 
  4. ^ Berg G, Roskot N, Smalla K (1999). "Genotypic and phenotypic relationships between clinical and environmental isolates of Stenotrophomonas maltophilia". J Clin Microbiol 37 (11): 3594–600. PMC 85701. PMID 10523559. 
  5. ^ McGowan J (2006). "Resistance in nonfermenting gram-negative bacteria: multidrug resistance to the maximum". Am J Med 119 (6 Suppl 1): S29–36; discussion S62–70. doi:10.1016/j.amjmed.2006.03.014. PMID 16735148. 
  6. ^ Waters V, Gómez M, Soong G, Amin S, Ernst R, Prince A (2007). "Immunostimulatory properties of the emerging pathogen Stenotrophomonas maltophilia (Epub ahead of print)". Infect Immun 75 (4): 1698–703. doi:10.1128/IAI.01469-06. PMC 1865680. PMID 17220304. 
  7. ^ Denton, M; Kerr, KG (1998). "Microbiological and Clinical Aspects of Infection Associated with Stenotrophomonas maltophilia". Clinical Microbiology Reviews 11 (1): 57–80. PMC 121376. PMID 9457429. 
  8. ^ Wheat PF, Winstanley TG, Spencer RC (1985). "Effect of temperature of antimicrobial susceptibilities of Pseudomonas maltophilia.". J Clin Pathol 38 (9): 1055–8. doi:10.1136/jcp.38.9.1055. PMC 499358. PMID 4044874. 
  9. ^ Wilcox MH, Winstanley TG, Spencer RC (1994). "Outer membrane protein profiles of Xanthomonas maltophilia isolates displaying temperature-dependant susceptibility to gentamicin". J antimicrob Chemother 33: 633–666. doi:10.1093/jac/33.3.663. 
  10. ^ Pankuch GA, Jacobs MR, Applebaum PC (1994). "Susceptibilities of 123 Xanthomonas maltophilia strains to clinafloxacin, PD131628, PD138312, PD140248, ciprofloxacin, and ofloxacin". Antimicrob Agents Chemother 38 (2): 369–370. doi:10.1128/AAC.38.2.369. PMC 284459. PMID 8192468. 
  11. ^ Pankuch GA, Jacobs MR, Rittenhouse SF, Appelbaum PC (1994). "Susceptibilities of 123 strains of Xanthomonas maltophilia to eight beta-lactams (including beta-lactam-beta-lactamase inhibitor combinations) and ciprofloxacin tested by five methods.". Antimicrob Agents Chemother 38 (10): 2317–22. doi:10.1128/AAC.38.10.2317. PMC 284737. PMID 7840563. 
  12. ^ Al-Jasser A (2006). "Stenotrophomonas maltophilia resistant to trimethoprim-sulfamethoxazole: an increasing problem". Ann Clin Microbiol Antimicrob 5: 23. doi:10.1186/1476-0711-5-23. PMC 1578578. PMID 16978420. 
  13. ^ Kwa AL, Low JG, Lim TP, Leow PC, Kurup A, Tam VH (2008). "Independent predictors for mortality in patients with positive Stenotrophomonas maltophilia cultures.". Ann Acad Med Singapore 37 (10): 826–30. PMID 19037515. 
  14. ^ Falagas ME, Kastoris AC, Vouloumanou EK, Rafailidis PI, Kapaskelis AM, Dimopoulos G (2009). "Attributable mortality of Stenotrophomonas maltophilia infections: a systematic review of the literature.". Future Microbiol 4 (9): 1103–9. doi:10.2217/fmb.09.84. PMID 19895214. 
  15. ^ Paez JI, Costa SF (2008). "Risk factors associated with mortality of infections caused by Stenotrophomonas maltophilia: a systematic review.". J Hosp Infect 70 (2): 101–8. doi:10.1016/j.jhin.2008.05.020. PMID 18621440. 

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