Ansari et al identified risk factors for infection with multidrug-resistant Stenotrophomonas maltophilia (nee Pseudomonas maltophilia) in a patient with cancer. Infections with multidrug-resistant strains are associated with an increased mortality rate, risk of spread to other patients and difficult therapeutic choices. The authors are from the University of Texas M.D. Anderson Cancer Center in Houston.


Criteria for a strain to be considered multidrug-resistant - both of the following:

(1) resistance to trimethoprim-sulfamethoxazole (TMP-SMX)

(2) resistance to >=2 of the following: ciprofloxacin, ceftazidime, amikacin, ticarcillin-clavulanate


Control groups used to determine risk:

(1) comparable risk for S. maltophilia (C controls)

(2) infection with susceptible strains of S. maltophilia (S controls)


Reference time: isolation of multidrug-resistant strain in culture


Risk factors infection with a multidrug-resistant strain (odds ratios 3.2 to 6.0):

(1) therapy with carbapenem in previous 90 days (vs C controls)

(2) therapy with quinolone in previous 90 days (vs C controls)

(3) therapy with trimethoprim-sulfamethoxazole (TMP-SMX) in previous 90 days (vs S controls)

(4) ICU admission in previous 30 days (vs C controls)

(5) history of S. maltophilia infection during previous year (vs S controls)


Factors associated with reduced risk of infection with a multidrug-resistant strain:

(1) non-ICU hospitalization within previous 30 days (vs both C and S controls)

(2) therapy with cephalosporin in previous 90 days (vs S controls)



• The patients were treated at M.D. Anderson Cancer Hospital. The prevalence of infection with Stenotrophomonas maltophilia may be different at other hospitals.


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