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Stenotrophomonas Maltophilia

  • Author: Burke A Cunha, MD; Chief Editor: Michael Stuart Bronze, MD  more...
Updated: Mar 18, 2016


Stenotrophomonas (Xanthomonas) maltophilia is an aerobic gram-negative bacillus that is found in various aquatic environments. Although an uncommon pathogen in humans, S maltophilia infection in humans, especially nosocomial, has been increasingly recognized.

S maltophilia is an organism of low virulence and frequently colonizes fluids used in the hospital setting (eg, irrigation solutions, intravenous fluids) and patient secretions (eg, respiratory secretions, urine, wound exudates). S maltophilia usually must bypass normal host defenses to cause human infection. For example, if an irrigation solution becomes colonized with this organism, irrigating an open wound can cause colonization or infection of the wound. S maltophilia is usually incapable of causing disease in healthy hosts without the assistance of invasive medical devices that bypass normal host defenses.[1]

Risk factors associated with S maltophilia infection have been defined and may include underlying malignancy, immunosuppressant therapy, cystic fibrosis, and exposure to broad-spectrum antibiotics.



S maltophilia has few pathogenic mechanisms and, for this reason, predominantly results in colonization rather than infection. If infection does occur, invasive medical devices are usually the vehicles through which the organism bypasses normal host defenses. Otherwise, the pathophysiology of this nonfermentative aerobic gram-negative bacillus does not differ from other nonfermentative aerobic organisms.




United States

S maltophilia is a noninvasive organism that has low virulence. It frequently colonizes body fluids but rarely causes infection (eg, intravenous line infections).


S maltophilia frequently colonizes the respiratory tract in patients with cystic fibrosis.[2, 3, 4, 5, 6]


Mortality and morbidity relate to the inoculum of S maltophilia that is able to bypass normal host defense mechanisms.

If an intravenous infusion contains large numbers of S maltophilia, then direct injection into the bloodstream may result in the signs and symptoms associated with gram-negative bacteremia.

Similarly, in the urinary tract, if urological irrigation fluids that contain large numbers of S maltophilia are used during an invasive urological procedure, eg, cystoscopy, then gram-negative bacteremia may occur with its attendant mortality and morbidity, which depend on host factors.

Contributor Information and Disclosures

Burke A Cunha, MD Professor of Medicine, State University of New York School of Medicine at Stony Brook; Chief, Infectious Disease Division, Winthrop-University Hospital

Burke A Cunha, MD is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Michael Stuart Bronze, MD David Ross Boyd Professor and Chairman, Department of Medicine, Stewart G Wolf Endowed Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center; Master of the American College of Physicians; Fellow, Infectious Diseases Society of America

Michael Stuart Bronze, MD is a member of the following medical societies: Alpha Omega Alpha, American Medical Association, Oklahoma State Medical Association, Southern Society for Clinical Investigation, Association of Professors of Medicine, American College of Physicians, Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Additional Contributors

Charles S Levy, MD Associate Professor, Department of Medicine, Section of Infectious Disease, George Washington University School of Medicine

Charles S Levy, MD is a member of the following medical societies: American College of Physicians, Infectious Diseases Society of America, Medical Society of the District of Columbia

Disclosure: Nothing to disclose.

  1. Araoka H, Baba M, Yoneyama A. Risk factors for mortality among patients with Stenotrophomonas maltophilia bacteremia in Tokyo, Japan, 1996-2009. Eur J Clin Microbiol Infect Dis. 2010 May. 29(5):605-8. [Medline].

  2. Burdge DR, Noble MA, Campbell ME, et al. Xanthomonas maltophilia misidentified as Pseudomonas cepacia in cultures of sputum from patients with cystic fibrosis: a diagnostic pitfall with major clinical implications. Clin Infect Dis. 1995 Feb. 20(2):445-8. [Medline].

  3. Denton M. Stenotrophomonas maltophilia: An emerging problem in cystic fibrosis patients. Rev Med Microbiol. 1997. 8:15-9.

  4. Hadjiliadis D, Steele MP, Chaparro C, et al. Survival of lung transplant patients with cystic fibrosis harboring panresistant bacteria other than Burkholderia cepacia, compared with patients harboring sensitive bacteria. J Heart Lung Transplant. 2007 Aug. 26(8):834-8. [Medline].

  5. Paschoal IA, de Oliveira Villalba W, Bertuzzo CS, et al. Cystic fibrosis in adults. Lung. 2007 Mar-Apr. 185(2):81-7. [Medline].

  6. Colin AA, Rabin HR. Stenotrophomonas maltophilia in cystic fibrosis: guilty or innocent?. Am J Respir Crit Care Med. 2011 Mar 1. 183(5):564-6. [Medline].

  7. Gopalakrishnan R, Hawley HB, Czachor JS, et al. Stenotrophomonas maltophilia infection and colonization in the intensive care units of two community hospitals: A study of 143 patients. Heart Lung. 1999 Mar-Apr. 28(2):134-41. [Medline].

  8. Farrell DJ, Sader HS, Jones RN. Antimicrobial susceptibilities of a worldwide collection of Stenotrophomonas maltophilia isolates tested against tigecycline and agents commonly used for S. maltophilia infections. Antimicrob Agents Chemother. 2010 Jun. 54(6):2735-7. [Medline]. [Full Text].

  9. Gülmez D, Cakar A, Sener B, Karakaya J, Hasçelik G. Comparison of different antimicrobial susceptibility testing methods for Stenotrophomonas maltophilia and results of synergy testing. J Infect Chemother. 2010 Oct. 16(5):322-8. [Medline].

  10. Abbott IJ, Slavin MA, Turnidge JD, Thursky KA, Worth LJ. Stenotrophomonas maltophilia: emerging disease patterns and challenges for treatment. Expert Rev Anti Infect Ther. 2011 Apr. 9(4):471-88. [Medline].

  11. Alonso A, Martínez JL. Multiple antibiotic resistance in Stenotrophomonas maltophilia. Antimicrob Agents Chemother. 1997 May. 41(5):1140-2. [Medline].

  12. Ansari SR, Hanna H, Hachem R, et al. Risk factors for infections with multidrug-resistant Stenotrophomonas maltophilia in patients with cancer. Cancer. 2007 Jun 15. 109(12):2615-22. [Medline].

  13. Azak A, Kocak G, Huddam B, Iscan G, Duranay M. An unusual cause of continuous ambulatory peritoneal dialysis-associated outpatient peritonitis: Stenotrophomonas maltophilia. Am J Infect Control. 2011 Sep. 39(7):618. [Medline].

  14. Barchitta M, Cipresso R, Giaquinta L, Romeo MA, Denaro C, Pennisi C, et al. Acquisition and spread of Acinetobacter baumannii and Stenotrophomonas maltophilia in intensive care patients. Int J Hyg Environ Health. 2009 May. 212(3):330-7. [Medline].

  15. Belvisi V, Fabietti P, Del Borgo C, Marocco R, DI Vincenzo E, Soscia F, et al. Successful treatment of Stenotrophomonas maltophilia soft tissue infection with tigecycline: a case report. J Chemother. 2009 Jun. 21(3):367-8. [Medline].

  16. Berbari N, Johnson DH, Cunha BA. Xanthomonas maltophilia peritonitis in a patient undergoing peritoneal dialysis. Heart Lung. 1993 May-Jun. 22(3):282-3. [Medline].

  17. Betts JW, Phee LM, Woodford N, Wareham DW. Activity of colistin in combination with tigecycline or rifampicin against multidrug-resistant Stenotrophomonas maltophilia. Eur J Clin Microbiol Infect Dis. 2014 Sep. 33(9):1565-72. [Medline].

  18. Blanquer D, De Otero J, Padilla E, Gómez F, Mayol A, Irigaray R, et al. Tigecycline for treatment of nosocomial-acquired pneumonia possibly caused by multi-drug resistant strains of Stenotrophomonas maltophilia. J Chemother. 2008 Dec. 20(6):761-3. [Medline].

  19. Brooke JS. Stenotrophomonas maltophilia: an emerging global opportunistic pathogen. Clin Microbiol Rev. 2012 Jan. 25(1):2-41. [Medline]. [Full Text].

  20. Cunha BA. Antibiotic Essentials. 5th ed. Royal Oak, Mich: Physicians Press; 2006.

  21. Cunha BA. Pseudoinfections and pseudo-outbreaks. Mayhall G, ed. Hospital Epidemiology and Infection Control. 2nd ed. Philadelphia, Pa: Lippencott Williams and Wilkins; 1999. 121-30.

  22. Cunha BA. Infections caused by non-fermentative aerobic gram-negative bacilli in the Critical Care Unit. Antibiotics for Clinicians. 2000. 4:11-6.

  23. Cunha BA. Pneumoniae Essentials. 2nd Ed. Royal Oak, MI: Physicians Press; 2008.

  24. Cunha BA, Klein NC. Pseudoinfections: A review. Infect Dis Clin Pract. 1995. 4:95-103.

  25. De Mauri A, Torreggiani M, Chiarinotti D, Andreoni S, Molinari G, De Leo M. Stenotrophomonas maltophilia: an emerging pathogen in dialysis units. J Med Microbiol. 2014 Nov. 63:1407-1410. [Medline].

  26. Denton M, Kerr KG. Microbiological and clinical aspects of infection associated with Stenotrophomonas maltophilia. Clin Microbiol Rev. 1998 Jan. 11(1):57-80. [Medline].

  27. Ece G, Erac B, Limoncu MH, Baysak A, Oz AT, Ceylan KC. Stenotrophomonas maltophilia Pseudo-outbreak at a University Hospital Bronchoscopy Unit in Turkey. West Indian Med J. 2014 Jan. 63(1):59-61. [Medline].

  28. Elting LS, Bodey GP. Septicemia due to Xanthomonas species and non-aeruginosa Pseudomonas species: increasing incidence of catheter-related infections. Medicine (Baltimore). 1990 Sep. 69(5):296-306. [Medline].

  29. Elting LS, Khardori N, Bodey GP, et al. Nosocomial infection caused by Xanthomonas maltophilia: a case-control study of predisposing factors. Infect Control Hosp Epidemiol. 1990 Mar. 11(3):134-8. [Medline].

  30. Entenza JM, Moreillon P. Tigecycline in combination with other antimicrobials: a review of in vitro, animal and case report studies. Int J Antimicrob Agents. 2009 Jul. 34(1):8.e1-9. [Medline].

  31. Falagas ME, Kastoris AC, Vouloumanou EK, Dimopoulos G. Community-acquired Stenotrophomonas maltophilia infections: a systematic review. Eur J Clin Microbiol Infect Dis. 2009 Jul. 28(7):719-30. [Medline].

  32. Falagas ME, Valkimadi PE, Huang YT, Matthaiou DK, Hsueh PR. Therapeutic options for Stenotrophomonas maltophilia infections beyond co-trimoxazole: a systematic review. J Antimicrob Chemother. 2008 Nov. 62(5):889-94. [Medline].

  33. Fang FC, Madinger NE. Resistant nosocomial gram-negative bacillary pathogens: Acinetobacter baumannii, Xanthomonas maltophilia, and Pseudomonas cepacia. Curr Clin Top Infect Dis. 1996. 16:52-83. [Medline].

  34. Farrell DJ, Sader HS, Jones RN. Antimicrobial susceptibilities of a worldwide collection of Stenotrophomonas maltophilia isolates tested against tigecycline and agents commonly used for S. maltophilia infections. Antimicrob Agents Chemother. 2010 Jun. 54(6):2735-7. [Medline]. [Full Text].

  35. Fujita J, Yamadori I, Xu G, et al. Clinical features of Stenotrophomonas maltophilia pneumonia in immunocompromised patients. Respir Med. 1996 Jan. 90(1):35-8. [Medline].

  36. Garazi M, Singer C, Tai J, Ginocchio CC. Bloodstream infections caused by Stenotrophomonas maltophilia: a seven-year review. J Hosp Infect. 2012 Jun. 81(2):114-8. [Medline].

  37. Garcia-Rodriguez JA, Garcia Sanchez JE, Munoz Bellido JL, et al. In-vitro activity of meropenem, a new carbapenem, against imipenem-resistant Pseudomonas aeruginosa and Xanthomonas maltophilia. J Chemother. 1991 Jun. 3(3):143-6. [Medline].

  38. Garcia-Teresa MA, Casado-Flores J, Delgado Dominguez MA, et al. Infectious complications of percutaneous central venous catheterization in pediatric patients: a Spanish multicenter study. Intensive Care Med. 2007 Mar. 33(3):466-76. [Medline].

  39. Garrison MW, Anderson DE, Campbell DM, et al. Stenotrophomonas maltophilia: emergence of multidrug-resistant strains during therapy and in an in vitro pharmacodynamic chamber model. Antimicrob Agents Chemother. 1996 Dec. 40(12):2859-64. [Medline].

  40. Gilardi GL. Characterization of nonfermentative nonfastidious gram negative bacteria encountered in medical bacteriology. J Appl Bacteriol. 1971 Sep. 34(3):623-44. [Medline].

  41. Gilardi GL. Infrequently encountered Pseudomonas species causing infection in humans. Ann Intern Med. 1972 Aug. 77(2):211-5. [Medline].

  42. Gilardi GL. Pseudomonas maltophilia infections in man. Am J Clin Pathol. 1969 Jan. 51(1):58-61. [Medline].

  43. Hansen CR. Stenotrophomonas maltophilia: to be or not to be a cystic fibrosis pathogen. Curr Opin Pulm Med. 2012 Nov. 18(6):628-31. [Medline].

  44. Cunha Ba. Infectious Disease in Critical Care Medicine. 2nd Ed. New York, NY: Informa Healthcare; 2007.

  45. Kagen J, Zaoutis TE, McGowan KL, et al. Bloodstream infection caused by Stenotrophomonas maltophilia in children. Pediatr Infect Dis J. 2007 Jun. 26(6):508-12. [Medline].

  46. Khardori N, Elting L, Wong E. Nosocomial infections due to Xanthomonas maltophilia (Pseudomonas maltophilia) in patients with cancer. Rev Infect Dis. 1990 Nov-Dec. 12(6):997-1003. [Medline].

  47. Khardori N, Reuben A, Rosenbaum B, et al. In vitro susceptibility of Xanthomonas (Pseudomonas) maltophilia to newer antimicrobial agents. Antimicrob Agents Chemother. 1990 Aug. 34(8):1609-10. [Medline].

  48. Krcmery V, Antal M, Langsadl L, et al. Transferable amikacin resistance in pseudomonas maltophilia and acinetobacter calcoaceticus. Infection. 1985 Mar-Apr. 13(2):89-90. [Medline].

  49. Lakatos B, Jakopp B, Widmer A, Frei R, Pargger H, Elzi L, et al. Evaluation of treatment outcomes for Stenotrophomonas maltophilia bacteraemia. Infection. 2014 Jun. 42(3):553-8. [Medline].

  50. Looney WJ, Narita M, Mühlemann K. Stenotrophomonas maltophilia: an emerging opportunist human pathogen. Lancet Infect Dis. 2009 May. 9(5):312-23. [Medline].

  51. Matsuyama JR, Beail B, Wallis C, et al. Susceptibility of Xanthomonas maltophilia and amikacin-resistant gram-negative bacteria to newer antimicrobials. Clin Pharm. 1991 Jul. 10(7):544-8. [Medline].

  52. Milne KE, Gould IM. Combination antimicrobial susceptibility testing of multidrug-resistant Stenotrophomonas maltophilia from cystic fibrosis patients. Antimicrob Agents Chemother. 2012 Aug. 56(8):4071-7. [Medline]. [Full Text].

  53. Milne KE, Gould IM. Combination antimicrobial susceptibility testing of multidrug-resistant Stenotrophomonas maltophilia from cystic fibrosis patients. Antimicrob Agents Chemother. 2012 Aug. 56(8):4071-7. [Medline]. [Full Text].

  54. Morrison AJ Jr, Hoffmann KK, Wenzel RP. Associated mortality and clinical characteristics of nosocomial Pseudomonas maltophilia in a university hospital. J Clin Microbiol. 1986 Jul. 24(1):52-5. [Medline].

  55. Nicodemo AC, Paez JI. Antimicrobial therapy for Stenotrophomonas maltophilia infections. Eur J Clin Microbiol Infect Dis. 2007 Apr. 26(4):229-37. [Medline].

  56. Nseir S, Di Pompeo C, Brisson H, et al. Intensive care unit-acquired Stenotrophomonas maltophilia: incidence, risk factors, and outcome. Crit Care. 2006. 10(5):R143. [Medline].

  57. Sattler CA, Mason EO Jr, Kaplan SL. Nonrespiratory Stenotrophomonas maltophilia infection at a children's hospital. Clin Infect Dis. 2000 Dec. 31(6):1321-30. [Medline].

  58. Saugel B, Eschermann K, Hoffmann R, et al. Stenotrophomonas maltophilia in the respiratory tract of medical intensive care unit patients. Eur J Clin Microbiol Infect Dis. 2012 Jul. 31(7):1419-28. [Medline].

  59. Semel JD, Trenholme GM, Harris AA, et al. Pseudomonas maltophilia pseudosepticemia. Am J Med. 1978 Mar. 64(3):403-6. [Medline].

  60. Shigemura K, Arakawa S, Tanaka K, Fujisawa M. Clinical investigation of isolated bacteria from urinary tracts of hospitalized patients and their susceptibilities to antibiotics. J Infect Chemother. 2009 Feb. 15(1):18-22. [Medline].

  61. Shiratori S, Wakasa K, Okada K, Sugita J, Akizawa K, Shigematsu A, et al. Stenotrophomonas maltophilia infection during allogeneic hematopoietic stem cell transplantation: a single-center experience. Clin Transplant. 2014 Jun. 28(6):656-61. [Medline].

  62. Steere AC, Tenney JH, Mackel DC. Pseudomonas species bacteremia caused by contaminated normal human serum albumin. J Infect Dis. 1977 May. 135(5):729-35. [Medline].

  63. Sutter VL. Identification of Pseudomonas species isolated from hospital environment and human sources. Appl Microbiol. 1968 Oct. 16(10):1532-8. [Medline].

  64. Tekce YT, Erbay A, Cabadak H, Sen S. Tigecycline as a therapeutic option in Stenotrophomonas maltophilia infections. J Chemother. 2012 Jun. 24(3):150-4. [Medline].

  65. Vidigal PG, Dittmer S, Steinmann E, Buer J, Rath PM, Steinmann J. Adaptation of Stenotrophomonas maltophilia in cystic fibrosis: molecular diversity, mutation frequency and antibiotic resistance. Int J Med Microbiol. 2014 Jul. 304(5-6):613-9. [Medline].

  66. Villarino ME, Stevens LE, Schable B, et al. Risk factors for epidemic Xanthomonas maltophilia infection/colonization in intensive care unit patients. Infect Control Hosp Epidemiol. 1992 Apr. 13(4):201-6. [Medline].

  67. Waters V, Atenafu EG, Lu A, Yau Y, Tullis E, Ratjen F. Chronic Stenotrophomonas maltophilia infection and mortality or lung transplantation in cystic fibrosis patients. J Cyst Fibros. 2013 Jan 4. [Medline].

  68. Wilsher ML, Kolbe J, Morris AJ, et al. Nosocomial acquisition of Burkholderia gladioli in patients with cystic fibrosis. Am J Respir Crit Care Med. 1997 Apr. 155(4):1436-40. [Medline].

  69. Wishart MM, Riley TV. Infection with Pseudomonas maltophilia hospital outbreak due to contaminated disinfectant. Med J Aust. 1976 Nov 6. 2(19):710-2. [Medline].

  70. Wu Y, Shao Z. High-dosage tigecycline for Stenotrophomonas maltophilia bacteremia. Chin Med J (Engl). 2014. 127(17):3199. [Medline].

  71. Yeshurun M, Gafter-Gvili A, Thaler M, et al. Clinical characteristics of Stenotrophomonas maltophilia infection in hematopoietic stem cell transplantation recipients: a single center experience. Infection. 2010 Jun. 38(3):211-5. [Medline].

  72. Yu VL, Rumans LW, Wing EJ, et al. Pseudomonas maltophilia causing heroin-associated infective endocarditis. Arch Intern Med. 1978 Nov. 138(11):1667-71. [Medline].

  73. Chang YT, Lin CY, Chen YH, Hsueh PR. Update on infections caused by Stenotrophomonas maltophilia with particular attention to resistance mechanisms and therapeutic options. Front Microbiol. 2015. 6:893. [Medline].

  74. Sánchez MB. Antibiotic resistance in the opportunistic pathogen Stenotrophomonas maltophilia. Front Microbiol. 2015. 6:658. [Medline].

  75. Juhász E, Krizsán G, Lengyel G, Grósz G, Pongrácz J, Kristóf K. Infection and colonization by Stenotrophomonas maltophilia: antimicrobial susceptibility and clinical background of strains isolated at a tertiary care centre in Hungary. Ann Clin Microbiol Antimicrob. 2014 Dec 31. 13:333. [Medline].

  76. Hand E, Davis H, Kim T, Duhon B. Monotherapy with minocycline or trimethoprim/sulfamethoxazole for treatment of Stenotrophomonas maltophilia infections. J Antimicrob Chemother. 2016 Apr. 71 (4):1071-5. [Medline].

  77. De Mauri A, Torreggiani M, Chiarinotti D, Andreoni S, Molinari G, De Leo M. Stenotrophomonas maltophilia: an emerging pathogen in dialysis units. J Med Microbiol. 2014 Nov. 63 (Pt 11):1407-10. [Medline].

  78. Cunha CB, Cunha BA. Antibiotic Essentials. 15th ed. New Delhi: JayPee Medical Publishers; 2016.

  79. Cunha BA. Antibiotic Essentials. 3rd ed. Sudbury, MA: Jones & Bartlett; 2010.

  80. Cunha BA. Infectious Disease in Critical Care Medicine. 3rd ed. New York, NY: Informa Healthcare; 2010.

Table 1. Hospital-Acquired S maltophilia Infections
Infection Predisposing Factor
Catheter-associated bacteriuria Indwelling urinary catheters
Intravenous line infections Central intravenous catheters
Urosepsis Urinary tract instrumentation
Primary bacteremia Arterial monitoring devices
Pseudobacteremia Contamination of blood during collection/processing of blood cultures
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