Drug-resistant organisms are common in fecal surveillance cultures, predict bacteremia and correlate with poorer outcomes in patients undergoing allogeneic stem cell transplants.

Abstract

With the increasing incidence of multidrug-resistant (MDR) organisms and high mortality rates associated with these infections, we describe the spectrum of the major drug-resistant pathogens identified in fecal surveillance, and re-visit the use of fecal surveillance in predicting infection with these organisms post-allogeneic stem cell transplant. Data from allogeneic stem cell transplant recipients with common drug-resistant strains of bacteria in fecal surveillance (Escherichia coli, Klebsiella spp., and Enterococcus spp.) were compared with recipients who did not have the same in fecal surveillance cultures. Baseline characteristics and post-transplant outcomes including similar drug resistance in blood cultures, severe sepsis, and 100-day transplant-related mortality were compared. Multivariate analysis using logistic regression model was used to determine independent predictors of outcome. In 232 transplants, the prevalence of common drug-resistant isolates in fecal surveillance cultures was 57.7% (134 out of 232 patients-with a single isolate in 115 and ≥2 isolates in the remaining 19 patients. A total of 164 drug-resistant isolates were obtained from 134 patients. Of the 164 isolates, 133 (81%) were positive for ESBL screening, 19 (11.5%) for carbapenem-resistant organisms (CRO) screening, 12 (7.3%) for VRE screening. Patients who had common drug-resistant pathogens detected in fecal surveillance have significantly higher subsequent blood culture positivity with drug resistance, as well as higher 100-day mortality. Factors influencing 100-day mortality included patient's age (P=.001), drug resistance positivity in blood (P<.001), drug resistance in fecal surveillance (P=.011), use of an alternate donor (other than fully matched sibling) (P<.001), GVHD grade 3-4 (P<.001), and severe sepsis (P<.001). On multivariate analysis, only use of an alternate donor (0.024), severe sepsis (P<.001), and grade 3-4 GVHD (P<.001) retained significance in predicting 100-day mortality. Organisms resistant to 3rd generation cephalosporins are frequently seen on fecal surveillance in the pre-transplant setting and are associated with a higher incidence of drug-resistant organisms in subsequent blood cultures (not limited to the same drug resistance pattern as seen in fecal surveillance). Drug-resistant organisms in fecal surveillance are associated with poorer outcomes following allogeneic stem cell transplant and may be used as a guide to identify patients at risk of subsequently developing a drug-resistant organism in blood.