S293: a novel approach of dual metagenomics next-generation sequencing for early diagnosis of blood stream infection in hematologic patients with febrile neutropenia: a multicenter, prospective study

Background: Bloodstream infection (BSI) is a lethal complication in hematologic patients with febrile neutropenia (FN). The delayed diagnosis and intervention will lead to significant mortality. Unfortunately, the traditional golden standard diagnostic method using blood culture (BC) can only identified pathogens in 20-30% patients with BSI, and usually needs more than 48 hours. Therefore, novel methods with fast turnover, improved sensitivity and specificity is needed. Metagenomics next-generation sequencing (mNGS) shows promise as diagnostic testing for difficult and critical infectious diseases in immunodeficient hosts. We recently established a novel dual mNGS approach detecting using plasma cfDNA and blood corpuscle. Still, its significance in BSI of hematological patients remains unclear and has not been evaluated in a prospective study. Aims: To evaluate the ability of dual mNGS to early identify infectious etiologies in FN patients with BSI. Methods: This study was prospective performed in four Chinese hematologic centers since October 2021. For consecutive patients aged ≥15 years with hematologic diseases, patients were screened at the onset of neutropenia. At the onset of FN, peripheral blood specimens were collected per subject for simultaneous BC and dual mNGS (separate sequencing for plasma and blood corpuscle). All patients will be followed for 14 days, or until death before 14 days. The intervention was per the attending physician. The results of dual mNGS bio-informatic analysis were determined according to the reference literature, the abundance in each sample and relative to other samples in the cohort. Clinical physician and mNGS analysis team were double-blind. The primary endpoint of this study was the diagnostic performance of dual mNGS. The positive agreement was defined as mNGS identified at least one same pathogen as initial BC. The negative agreement was defined as both mNGS and BC were negative. And the adjudication of the result of BC, mNGS, and clinical diagnosis was evaluated by 4 independent specialists in hematology. This study was registerd on ClinicalTrials.gov ID: NCT05149547. Results: During the study period, 300 FN events were enrolled in the final analysis. According to the clinical adjudication, the 300 FN events were adjudged as 62 Definite BSI, 61 Probable BSI, 116 infectious FN other than BSI, 55 Non-infectious FN events and 6 FN of indeterminate cause. Among the 62 definite BSI, clinical adjudication categorized dual mNGS results as: Definite (N=49); Probable (N=7); Possible (N=3); Unlikely (N=1); Negative (N=2). Definite, probable and possible cases were regarded as true positives. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of dual mNGS were 95.2%, 94.6%,95.2%, 94.6%, respectively. The positive percent agreement (PPA) and negative percent agreement (NPA) of dual mNGS with BC were 79.0%(49/62) and 34.9%(83/238) respectively. Compared with BC, the diagnostic time of dual mNGS was significant shorter (39.7±15.0 vs. 119.8±31.9 h, p < 0.0001). Real-time availability of dual mNGS results could have allowed early optimization of agents in 52.3% events, by addition or escalation of antibacterial in 31.7%, and antimicrobial narrowing in 20.6%. Summary/Conclusion: Our findings suggest that a novel dual mNGS approach has excellent diagnostic performance in early diagnosis of BSI in FN patients with hematological disorders. However, further studies need to be confirmed. Keywords: Neutropenia, Infection, Hematological malignancy