Clinical characteristics of Stenotrophomonas maltophilia infection in hematopoietic stem cell transplantation recipients: A single center experience

Background: Recipients of hematopoietic stem-cell transplantation (HSCT) are at high risk for infections caused by Stenotrophomonas maltophilia. Methods: We conducted a retrospective analysis of all infections caused by S. maltophilia in HSCT recipients in a single center in Israel during a 4 year period. Results: Of 570 patients undergoing HSCT, 19 patients with an invasive S. maltophilia infection were identified. Sixteen had allogeneic HSCT and 3 had autologous HSCT. Seventeen patients (90%) had an indwelling central venous catheter (CVC) at the time of infection. S. maltophilia infections were detected in three clinical settings: as a complication of prolonged neutropenia (n = 9), as a CVC-related non-neutropenic infection occurring after CVC manipulation (n = 8) and as a respiratory tract infection (n = 2). Eleven patients (58%) had a polymicrobial infection. Ten patients (52.6%) received carbapenems during the previous month. The treatment for all patients included broad spectrum antibiotics, which were switched according to susceptibilities upon identification of the isolates. All isolates were susceptible in vitro to TMP-SMX. CVCs were removed in 12 patients (70%). Six patients, all after allogeneic HSCT, died. The CVC was removed in only two of the five patients with CVCs who died. Conclusions: Stenotrophomonas maltophilia is an emerging nosocomial pathogen in HSCT recipients, both in the early neutropenic phase and in the non-neutropenic phase. It is commonly associated with the presence and manipulation of an indwelling CVC. Removal of the CVC in addition to appropriate antibiotic therapy (TMP-SMX) is crucial for infection control.