Risk factors for hospital acquisition of trimethoprim–sulfamethoxazole resistant Stenotrophomonas maltophilia in adults: A matched case-control study

Background/Purpose: The emergence of trimethoprim–sulfamethoxazole resistant Stenotrophomonas maltophilia (TSRSM) represents a serious threat to patients. The aim of current study was to identify risk factors associated with hospital-acquired TSRSM occurrence in adult inpatients. Methods: We conducted a matched case-control study in Tri-Service General Hospital, Taipei, Taiwan. From January 2014 through June 2015, case patients with TSRSM and control patients with trimethoprim–sulfamethoxazole susceptible S. maltophilia (TSSSM) during hospitalization were identified. Control patients were matched with TSRSM cases for age (within five years), sex, and site of isolation at a ratio of 1:1. Results: A total of 266 patients were included in our study (133 cases and 133 matched controls). Bivariable analysis showed that previous exposure to fluoroquinolone [odds ratio (OR), 2.693; 95% confidence interval (CI, 1.492–5.884; p = 0.002)], length of intensive care unit stay (OR, 1.015 per day; 95% CI, 1.001–1.030; p = 0.041), and length of hospital stay (OR, 1.012 per day; 95% CI, 1.002–1.023; p = 0.018) prior to S. maltophilia isolation were associated with TSRSM occurrence. A multivariable analysis showed that previous exposure to fluoroquinolone (OR, 3.158; 95% CI, 1.551–6.430; p = 0.002) was an independent risk factor for TSRSM occurrence after adjustment. Conclusion: Previous fluoroquinolone use was an independent risk factor for hospital-acquired TSRSM occurrence in adult inpatients, suggesting that judicious administration of fluoroquinolone may be important for limiting TSRSM occurrence.