Epidemiology, clinical features and prognosis of infections due to Stenotrophomonas maltophilia

INTRODUCTION. Stenotrophomonas maltophilia is a multiresistant pathogen that is being isolated with increasing frequency from patients with predisposing factors. Few studies have assessed the epidemiology and clinical relevance of this pathogen in various types of patients from general hospitals. METHODS. This is a prospective study performed in the cohort of patients with infection due to S. maltophilia in Hospital Univeritario Virgen Macarena (Seville, Spain) between January 1998 and January 2001. The following data were collected: demographics, underlying diseases, APACHE II score at admission, invasive procedures, previous antimicrobial treatment, systemic response, therapy and outcome. RESULTS. S. maltophilia was isolated from a clinical sample in 87 patients and was considered to be the cause of infection in 45 (52%) of them, who were included in the study. Among the total, 40% were in the ICU and 13% were outpatients. The infection was considered health care-associated in 91%; 82% had received antimicrobial treatment. The most frequent type of infection was pneumonia, followed by other infections of the respiratory tract, urinary tract infections, and skin and soft tissue infections. Criteria for severe sepsis or septic shock were present in 12%. The most common antimicrobials used were the combination trimethoprim-sulfamethoxazole (60%). Crude mortality was 44% and the only associated variable was the APACHE II score. Infection-related mortality was 13%; all deaths occurred in patients with pneumonia. CONCLUSION. S. maltophilia caused a wide range of health care-associated infections in debilitated patients, even though half the patients from whom the organism was isolated were considered only colonized. Crude mortality was associated with the severity of the baseline situation. Pneumonia was associated with high mortality.