Impact of Next-Generation Sequencing Cell-free Pathogen DNA Test on Antimicrobial Management in Adults with Hematological Malignancies and Transplant Recipients with Suspected Infections

Infections in adult patients with hematological malignancies (HM) and stem cell transplant (SCT) recipients are a significant cause of morbidity and mortality. A timely diagnosis of infections can have a major impact on outcomes. Tools that help rule out infectious causes of fever can decrease antibiotic use, toxicities, hospitalization costs, and potentially decrease antibiotic resistance in the long term. We retrospectively evaluated the ability of cell-free DNA next-generation sequencing (NGS) testing in the timely identification of pathogenic microorganisms and its impact on the antimicrobial management of immunocompromised patients with hematologic malignancies. In the period between 2018 to 2020, 95 samples were reviewed, of which 31 adult patients (32 tests) had hematologic malignancies or were recipients of SCT. The NGS tests were performed in the following patients: (a) patients with prolonged fever and negative conventional tests, (b) persistent fever despite positive conventional test and appropriate antimicrobials, and (c) fever-free patients with imaging suspicious for infection. The median time from fever to NGS sampling was 5 days (range, 1-28). The median time to NGS results was 2 days (range, 1-6). The NGS resulted in an escalation of antibiotics in 28% of cases (9/32) and de-escalation of antibiotics in 31% of cases (10/32). Overall, NGS testing changed management in nearly 59% (19/32) of patients. The sensitivity and specificity of NGS to detect clinically significant infection was 80% and 58%, respectively. The test identified uncommon and difficult to diagnose organisms such as Nocardia, Legionella, Toxoplasma and Pneumocystis jirovecii resulting in rapid antimicrobial interventions. In conclusion, in patients with HM or SCT recipients, microbial cell-free DNA sequencing allowed rapid and actionable treatment. This strategy can target appropriate antibiotic use, avoid overtreatment, and potentially decrease the hospital length-of-stay.