Targeted Next Generation Sequencing Is Comparable with Metagenomic Next Generation Sequencing in Hematological Malignancies with Suspected Pneumonia for Pathogenic Microorganism Detection

Pulmonary infections are commonly observed in hematologic malignancy (HM) patients.For HM patients with low immune functionality and high susceptibility to pulmonary infections, timely identification of pathogens and administration of correct medications can greatly improve patient outcomes[1, 2].The next generation sequencing can achieve an early diagnosis of respiratory infection.To date, the systematic evaluation of the clinical use of mNGS and tNGS for pneumonia in HM patients has been insufficient. A retrospective analysis was conducted on HM patients with suspected pneumonia admitted to the Hematology Department of The Third Xiangya Hospital between April 2019 and April 2024.A total of 234 patients were identified for analysis,including 126 patients used mNGS to detect bronchoalveolar lavage fluid(BALF）and 108 patients used mNGS to detect BALF.The purpose was to compare the diagnostic efficacy of mNGS and tNGS in pulmonary infection pathogens. The overall microbial detection rate of mNGS and tNGS were 88.9% (112/126) and 93.5% (101/108), respectively. And there was no significant difference between them ( p = 0.217).Viruses,bacteria and fungi accounted for 42.2%(117/277), 33.9% (94/277) and 23.8% (66/277) among the microorganisms detected in mNGS, respectively. Meanwhile,Viruses,bacteria and fungi accounted for 61.0%(147/241), 21.2% (51/241) and 17.8% (43/241) among the microorganisms detected in mNGS.In order to compare the diagnostic and concordance between mNGS and tNGS.We used the final clinical diagnosis as the “gold standard”.The sensitivity, specificity, positive predictive value and accuracy of mNGS were 92.7%,37.5%,91.1% and 85.7%, respectively, compared with 97.9%,45.5%,94.1% and 92.6% for tNGS.Further more,we compared the clinical impact of mNGS and tNGS on antibiotic usage.The mNGS results led to adjustments in antibiotic usage for 63 out of the 126 patients(56.3%). Following these alterations, 56 patients (88.9%) reported significant improvements.In tNGS,there are 59 out of the 108 patients(58.4%%) adjustmented in antibiotic usage and 56 patients(94.9%) reported significant improvements.The total death of mNGS and tNGS were 9.8%(11/126) and 4.0%（4/108), respectively. There were no significant differences between the two groups (P ＞0.05).Compared to the microbial range detected by tNGS, mNGS detected an additional 14 pathogenic microorganisms, in which had a very low proportion of pathogenic microorganisms (3.6%,4/112), which did not have any adverse effects on the clinical outcomes of patients. Collectively,we found that tNGS is comparable with mNGS in HM patients with suspected pneumonia for pathogenic microorganism detection.What's more,the ability of tNGS in guiding treatment was consistent with those of mNGS.