• Tahir Naeem
  • Muhammad Absar
  • Ali M Somily


Background: Stenotrophomonas maltophilia has emerged as a significant pathogen in compromisedpatients, causing infections which are difficult to treat. This study was carried out to comprehend therecent trend of antimicrobial resistance among clinical isolates of S. maltophilia and suggestmanagement guidance for patients in general and in our region in particular. Methods: A total of 222clinical isolates were tested between Jan 2003 to Jun 2009 at King Khalid University Hospital,College of Medicine, King Saud University, Riyadh Saudi Arabia. The organisms were identified asper standard guidelines. Final identification and minimum inhibitory concentration (MIC) wasdetermined by using Microscan®. Results: S. maltophilia showed absolute resistance to Imipenem.In vitro, least resistance was observed against Cotrimoxazole (9.45%) followed by Ceftazidime(57.21%), Piperacillin/Tazobactam (60.82%), Ciprofloxacin (77.03%), Aztreonam (86.03%).Gentamicin showed overall highest resistance (87.39%). The crude mortality rate was 47%.Conclusion: Cotrimoxazole is still the most effective agent against S. maltophilia but, keeping inview the increasing resistance to first and second line drugs, there is an urgent need for an effectivesurveillance system. To discourage development of resistance and devise an effective empiricaltherapy, large scale study should be considered.Keywords: Stenotrophomonas maltophilia, antibiotic resistance, mortality rate, minimum inhibitoryconcentration


Nicodemo AC, Araujo MRE, Ruiz AS, Gales AC. In vitro

susceptibility of Stenotrophomonas maltophilia isolates:

comparison of disc diffusion, Etest and agar dilution

methods. J Antimicrob Chemother 2004;53:604–8.

Nicodemo AC, Paez JI. Antimicrobial therapy for

Stenotrophomonas Maltophilia infections. Eur J Clin

Microbiol Infect Dis 2007;26:229–37.

Crossman LC, Gould VC, Dow JM, Vernikos GS, Okazaki

A, Sebaihia M, et el. The Complete genome comparative and

functional analysis of Stenotrophomonas maltophilia reveals

an organism heavily shielded by drug resistance

determinants. Genome Biol 2008;9:R74.

Al-Jasser AM. Stenotrophomonas maltophilia resistant to

trimethprim-sulfamethoxazole: an increasing problem. Ann

Clin Microbiol Antimicrob 2006;5:23.

Otkun MT, Gürcan S, Özer B, Aydoslu B, Bukavaz S. The

antimicrobial susceptibility of Stenotrophomonas maltophilia

isolates using three different methods and their genetic

relatedness. BMC Microbiol 2005,5:24.

J Ayub Med Coll Abbottabad 2012;24(2) 33

Clinical and Laboratory Standards Institute. M100-S17.

Performance standards for antimicrobial susceptibility

testing; 16th informational supplement. Wayne, PA: Clinical

and Laboratory Standards Institute; 2007.

Jumaa PA, Sonnevend A, Pàl T, Hag ME, Amith R, Trad O.

The molecular epidemiology of Stenotrophomonas

maltophilia bacteraemia in a tertiary referral hospital in the

United Arab Emirates 2000–2004. Ann Clin Microbiol

Antimicrob 2006;5:32.

Abbassi MS, Touati A, Achour W, Cherif Ab, Jabnoun S,

Khrouf N, et al. Stenotrophomonas maltophilia responsible

for respiratory infections in neonatal intensive care unit:

Antibiotic susceptibility and molecular typing. Pathol Biol

(Paris) 2009;57:363–7.

Del Toro MD, Rodriguez-Bano J, Herrero M, Rivero A,

Garcia-Ordonez MA, Corzo J, et al. Clinical epidemiology of

Stenotrophomonas maltophilia colonization and infection: a

multicenter study. Medicine (Baltimore) 2002:81:228–39.

Nicholson AM, Castle D, Akpaka P, Tennant I, Nelson M.

The emergence of Stenotrophomonas maltophilia as a

significant nosocomial pathogen at the University Hospital of

the West Indies. West Indian Med J 2004;53(1):17–22.

Denton M, Todd NJ, Kerr KG, Hawkey PM, Littlewood JM.

Molecular epidemiology of Stenotrophomonas maltophilia

isolated from clinical specimens from patients with cystic

fibrosis and associated environmental samples. J Clin

Microbiol 1998;36:1953–8.

Laing FBY, Ramotar K, Read RR, Alfieri N, Kureishi A,

Henderson EA, et al. Molecular epidemiology of

Xanthomonas maltophilia colonization and infection in the

hospital environment. J Clin Microbiol 1995;33:513–8.

Khardori N, Elting L, Wong E, Schable B, Bodey GP.

Nosocomial infections due to Xanthomonas maltophilia

(Pseudomonas maltophilia) in patients with cancer. Rev

Infect Dis 1991;12:997–1003.

Pathmanathan A, Waterer GW. Significance of positive

Stenotrophomonas maltophilia culture in acute respiratory

tract infection. Eur Respir J 2005;25(5):911–4.

Kwa AL, Low JG, Lim TP, Leow PC, Kurup A, Tam VH.

Independent predictors for mortality in patients with positive

Stenotrophomonas maltophilia cultures. Ann Acad Med

Singapore 2008;37(10):826–5.

Howe RA, Wilson MP, Walsh TR, Millar MR. Susceptibility

testing of Stenotrophomonas maltophilia to carbapenems. J

Antimicrob Chemother 1997;40:13–7.

Cantón R, Valdezate S, Vindel A, Sánchez Del Saz B, Maíz

L, Baquero F. Antimicrobial susceptibility profile of

molecular typed cystic fibrosis Stenotrophomonas

maltophilia isolates and differences with noncystic fibrosis

isolates. Pediatr Pulmonol 2003;35(2):99–107.

Caylan R, Kaklikkaya N, Aydin K, Aydin F, Yilmaz

G, Ozgumus B, et al. An epidemiological analysis of

Stenotrophomonas maltophilia strains in a university

hospital. Jpn J Infect Dis 2004;57:37–40.

Bayle S, Rovery C, Sbragia P, Raoult R, Brouqui P.

Stenotrophomonas maltophilia prosthetic valve endocarditis:

a case report. J Med Case Reports 2008;2:174.

C, Sanchez A, Palau L, Gomez M, Picazo JJ, Antibiotic

surveillance of S. maltophilia, 1993–1999. J Antimicrob

Chemother 2001;48:152–4.

Meyer E, Schwab F, Gastmeier P, Rueden H, Daschner FD,

Jonas D. Stenotrophomonas maltophilia and antibiotic use in

German intensive care units: data from Project SARI

(Surveillance of Antimicrobial Use and Antimicrobial

Resistance in German Intensive Care Units). J Hosp

Infect 2006;64:238–43.