Do Weekly Surveillance Cultures Contribute to Antibiotic Stewardship and Correlate with Outcome of HSCT in Children? A Multicenter Real-World Experience of 5 Years from the Indian Subcontinent

The utility of weekly rectal swab surveillance cultures (RSSCs) as a resource to identify gut colonization with extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli or Klebsiella pneumoniae carbapenemase (KPC)-producing organisms and guide empirical antibiotic therapy in hematopoietic stem cell transplantation (HSCT) recipients continues to be a subject of interest. There is an urgent need to assess and justify modifications to empirical antibiotics based on regional epidemiology and patient groups. This study aimed to study the utility of weekly rectal swab surveillance cultures (RSSCs) to guide empirical antibiotic therapy and to examine the impact of gut colonization on transplantation outcomes. This retrospective analysis of 317 successive first HSCTs performed mainly for hemoglobinopathies was conducted in 3 pediatric bone marrow transplantation centers in the Indian subcontinent between April 2016 and April 2021. Transplantation, infection control, and febrile neutropenia management protocols were identical in the 3 centers. First-line antibiotics were chosen based on RCCS reports, with meropenem used for ESBL and high-dose meropenem with colistin used for carbapenemase-resistant colonization for first half of the study, with no adjustment made in the second half. Clinical response to antibiotics, long-term outcomes, antibiotic-resistant bacteremia, and acute graft-versus-host disease (GVHD) were analyzed. The log-rank test, chi-square, and Wilcoxon rank-sum tests were used to compare data using R Statistical software. Of the 871 weekly RSSCs done, 162 were positive for ESBL- or KPC-resistant organism. RCCSs were ESBL-positive in 106 patients (33%) and KPC-positive in 10 patients (3%). Among the 97 ESBL-positive patients for whom a antimicrobial susceptibility testing report was available, only 22 (25%) demonstrated clinical resistance to piperacillin-tazobactam (Pip-Taz). Among the 10 KPC-positive patients, only 4 (40%) demonstrated clinical resistance to Pip-Taz and 3 (30%) had clinical resistance to meropenem. Two-thirds of patients with ESBL-positive RSSC in whom first-line empirical antibiotics were used responded clinically. Even among the 15 patients who were resistant to first-line empirical antibiotics (Pip-Taz) on RSSC reports, 67% responded clinically to Pip-Taz. Twenty-seven of these patients (56%) never needed carbapenem therapy. Empirical Pip-Taz therapy in ESBL-positive patients did not prolong meropenem use within 100 days of transplantation (P = .18). All patients with a KPC-positive RSSC who received first-line empirical antibiotics responded clinically, including 4 who were resistant to Pip-Taz and 3 who were meropenem-resistant on RCCS. Comparing patients who were ESBL-positive, KPC-positive, and not positive for either showed no statistically significant differences in overall survival (OS) (P = .95), disease-free survival (DFS) (P = .45), transplantation-related mortality (TRM) (P = .97), graft rejection (P = .68), or rate of acute GVHD grade II-IV (P = .78). No statistically significant differences were seen between the ESBL-positive patients who received and those who did not receive higher-level empirical antibiotics in OS (P = .32), DFS (P = .64), TRM (P = .65), graft rejection (P = .46), acute GVHD grade II-IV (P = .26), or antibiotic-resistant bacteremia (P = .3). In the context of HSCT for nonmalignant hematologic disorders, choosing empiric antibiotic therapy based on RSSCs is not justified, even in regions with a high prevalence of antimicrobial resistance. Antimicrobial susceptibility testing reports in surveillance cultures did not correlate with in vivo clinical response. Colonization reported on weekly RSSCs showed no correlation with clinical outcomes. © 2021 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc.