Septic Prepatellar Bursitis Caused by Stenotrophomonas (Xanthomonas) maltophilia

We describe an unusual case of bursitis caused by S. maltophilia that we believe is the first such case in the literature. A 72-year-old man presented with swelling, erythema, and pain of 14 days' duration in the left knee. Culture of the bursal fluid yielded S. maltophilia that was susceptible to trimethoprim-sulfamethoxazole, ticarcillin/clavulanic acid, and ciprofloxacin. Blood and urine cultures were sterile. Results of a radiological examination of both of the patient's knees were unremarkable. The patient was treated with ciprofloxacin (750 mg orally twice per day for 2 weeks) as an outpatient. The infection promptly resolved without the need for repeated aspirations of the prepataller bursa.