Stenotrophomonas (Xanthomonas) maltophilia: a multidrug-resistant nosocomial pathogen.

Stenotrophomonas (Xanthomonas) maltophilia is emerging as a multidrug-resistant nosocomial pathogen. In general, the organism is opportunistic, colonizing or infecting patients with predisposing risk factors such intensive care unit residence, malignancy, mechanical ventilation, and previous antibiotic exposure. It can cause a variety of infections depending on underlying patient-specific medical conditions. It is often part of multimicrobial infections, and determining its role as a pathogen is difficult. Trimethoprim-sulfamethoxazole (TMP-SMX) has traditionally been the most active agent against S. maltophilia. Other classes of antibiotics, with few exceptions, have not been effective. Synergistic antimicrobial combinations are now being investigated due to the bacteriostatic nature of TMP-SMX, and increasing reports of resistance to TMP-SMX. The combination of ticarcillin-clavulanate plus TMP-SMX appears to be the most promising regimen studied thus far.