- Benamu, Esther;
- Gajurel, Kiran;
- Anderson, Jill N;
- Lieb, Tullia;
- Gomez, Carlos A;
- Seng, Hon;
- Aquino, Romielle;
- Hollemon, Desiree;
- Hong, David K;
- Blauwkamp, Timothy A;
- Kertesz, Mickey;
- Blair, Lily;
- Bollyky, Paul L;
- Medeiros, Bruno C;
- Coutre, Steven;
- Zompi, Simona;
- Montoya, Jose G;
- Deresinski, Stan
Background
Standard testing fails to identify a pathogen in most patients with febrile neutropenia (FN). We evaluated the ability of the Karius microbial cell-free DNA sequencing test (KT) to identify infectious etiologies of FN and its impact on antimicrobial management.Methods
This prospective study (ClinicalTrials.gov; NCT02912117) enrolled and analyzed 55 patients with FN. Up to 5 blood samples were collected per subject within 24 hours of fever onset (T1) and every 2 to 3 days. KT results were compared with blood culture (BC) and standard microbiological testing (SMT) results.Results
Positive agreement was defined as KT identification of ≥1 isolate also detected by BC. At T1, positive and negative agreement were 90% (9/10) and 31% (14/45), respectively; 61% of KT detections were polymicrobial. Clinical adjudication by 3 independent infectious diseases specialists categorized Karius results as: unlikely to cause FN (N = 0); definite (N = 12): KT identified ≥1 organism also found by SMT within 7 days; probable (N = 19): KT result was compatible with a clinical diagnosis; possible (N = 10): KT result was consistent with infection but not considered a common cause of FN. Definite, probable, and possible cases were deemed true positives. Following adjudication, KT sensitivity and specificity were 85% (41/48) and 100% (14/14), respectively. Calculated time to diagnosis was generally shorter with KT (87%). Adjudicators determined real-time KT results could have allowed early optimization of antimicrobials in 47% of patients, by addition of antibacterials (20%) (mostly against anaerobes [12.7%]), antivirals (14.5%), and/or antifungals (3.6%); and antimicrobial narrowing in 27.3% of cases.Clinical trials registration
NCT02912117.Conclusion
KT shows promise in the diagnosis and treatment optimization of FN.