Application of metagenomics next-generation sequencing in monitoring Legionella pneumophila infection after allogeneic hematopoietic stem cell transplantation / 白血病·淋巴瘤

ABSTRACT

Objective@#To investigate the application of metagenomic next-generation sequencing (mNGS) in detection of the rare or difficult-to-cultivate pathogens.@*Methods@#One patient with acute lymphoblastic leukemia who went through allogeneic hematopoietic stem cell transplantation (allo-HSCT) developed symptoms of infection after transplantation. Conventional microbial culture, polymerase chain reaction (PCR), and mNGS combined with biological information analysis were performed with plasma and cerebrospinal fluid samples, the anti-infective treatment was adjusted according to the test results, and the efficacy was assessed.@*Results@#No suspected pathogens were detected by microbial culture and PCR in the cerebrospinal fluid and plasma samples since the patient developed infection symptoms. However, Legionella pneumophila was analyzed by mNGS in the cerebrospinal fluid specimen on day 23 after allo-HSCT (reads count 19 655), and it was considered as the principal pathogen after comprehensively evaluating the patient's clinical manifestations and the test results. Then the antimicrobial treatments were adjusted according to the patient's clinical manifestations and laboratory test results, and the number of gene sequences of Legionella pneumophila was monitored by mNGS method. Azithromycin, tigecycline, and other antibiotics effective for Legionella pneumophila were used after detecting this pathogen. A total of 15 mNGS analysis were performed during the 5-month period, and the highest number of Legionella pneumophila sequences monitored in the cerebrospinal fluid was 2 226, the lowest was 253 and eventually turned negative. The clinical symptoms and treatment outcomes were consistent with the mNGS monitoring results.@*Conclusions@#The mNGS technology has significant value in detection of the rare and difficult-to-cultivate pathogens. The mNGS technology provides a valuable supplement to microbial culture and PCR methods.