Clinical outcomes of persistent colonization with multidrug-resistant Gram-negative rods in adult patients undergoing single cord blood transplantation

Severe bacterial infections are a serious problem after cord blood transplantation (CBT). Colonization with multidrug-resistant Gram-negative rods (MRGNR) is associated with increased morbidity and mortality after allogeneic hematopoietic cell transplantation. However, its impact on outcomes after CBT is unclear. We aim to explore the impact of colonization with MRGNRs in adult patients undergoing CBT. We retrospectively analyzed 145 adult patients who received single-unit CBT in our institute. As a standard practice in our institute, all patients were screened for colonization with MRGNR by oral cavity swabs, urine, and stool specimens between the day of admission for CBT and the day of discharge or day 100 after CBT. There were 62 incidents of colonization with MRGNR in 52 patients, of which 25 involved Stenotrophomonas maltophilia, 19 multidrug-resistant Pseudomonas spp., and 18 extended-spectrum beta-lactamase-producing Enterobacteriaceae. On multivariate analysis, MRGNR persistence significantly affected increase in non-relapse mortality (NRM) (hazard ratio [HR], 8.96; 95% CI 1.85–43.46; P = 0.006) and the subsequent development of bloodstream infection due to MRGNR (HR 11.82; 95% CI 2.15–64.87; P = 0.004), but not MRGNR clearance, compared with non-colonized patients. These data suggest that persistent colonization with MRGNR is significantly associated with higher NRM in CBT for adults.