Clinical Impact of Colonization with Multidrug-Resistant Organisms on Outcome after Autologous Stem Cell Transplantation: A Retrospective Single-Center Study

- Colonization with multidrug-resistant organisms lead to inferior overall survival
- Main cause of death is infection in colonized patients
- There was no difference in nonrelapse mortality during neutropenia
- The period after discharge after transplantation seems most critical.

A significant increase in infections caused by multidrug-resistant organisms (MDRO) has been observed in recent years, resulting in an increase of mortality in all fields of health care. Hematological patients are particularly affected by MDRO infections because of disease- and therapy-related immunosuppression. To determine the impact of colonization with MDRO on overall survival, we retrospectively analyzed data from patients undergoing autologous hematopoietic stem cell transplantation at our institution. In total, 184 patients were identified, mainly patients with lymphomas (n = 98, 53.3%), multiple myelomas (n = 80, 43.5%), germ cell cancers (n = 5, 2.7%), or acute myeloid leukemia (n = 1, .5%). Forty patients (21.7%) tested positive for MDRO colonization. At a median follow-up time of 21.5 months, the main causes of death were infection in colonized and disease progression in noncolonized patients. Nonrelapse mortality (NRM) was higher in patients who tested positive for MDRO than in the noncolonized group (25.4% versus 3%, P < .001). Interestingly, NRM in neutropenia after autologous transplantation did not differ between colonized and noncolonized patients. Colonized patients, however, had inferior overall survival after autologous transplantation in univariate (61.7% versus 73.3%, P = .005) as well as in multivariate analysis (hazard ratio, 2.463; 95% confidence interval, 1.311 to 4.626; P = .005). We conclude that the period after discharge from hospital after autologous transplantation seems critical and patients with MDRO colonization should be observed closely for infections in the post-transplantation period in outpatient care.