Clinical and Microbiologic Outcomes in Trauma Patients Treated for Stenotrophomonas maltophilia Ventilator-Associated Pneumonia

Study Objectives. To determine clinical and microbiologic plus clinical success rates in critically ill trauma patients who received treatment for Stenotrophomonas maltophilia ventilator-associated pneumonia (VAP). Design. Retrospective medical record review. Setting. Level I trauma intensive care unit of a large academic medical center. Patients. A total of 101 patients who developed S. maltophilia VAP between January 1997 and December 2007. Measurements and Main Results. Patients' baseline demographic and clinical characteristics, as. well as characteristics of their VAP, were documented. The primary study outcome was the rate of clinical success in patients with S. maltophilia VAP; a secondary outcome was microbiologic plus clinical success rate in these patients. Standard definitions were employed to determine these outcomes related to VAP treatment. The study population had higher injury severity scores and a higher rate of traumatic brain injury than is typically observed in the study's intensive care unit. The median time to diagnosis of S. maltophilia VAP was 15 days (interquartile range 11-24 days). Stenotrophomonas maltophilia was the sole organism isolated in 34% of patient; the other patients had polymicrobial VAP. Despite inadequate empiric antibiotic therapy being administered to 97% of the patients, the overall clinical success rate was 87%. The microbiologic plus clinical success rate was 82%. The most common treatments for S. maltophilia VAP were trimethoprim-sulfamethoxazole (77 patients received monotherapy, 9 received combination therapy) and ciprofloxacin (6 patients received monotherapy 8 received combination therapy); all-cause and VAP-related mortality rates were 13% and 7%, respectively. Conclusion. Critically ill trauma patients with S. maltophilia VAP responded well to therapy despite high rates of inadequate empiric antibiotic administration. Trimethoprim-sulfamethoxazole was the most common therapy, but clinical success rates did not differ significantly based on antibiotic selection. This study adds significantly to the available S. maltophilia VAP outcomes data.