Comparison of mNGS and conventional culture in non-organ transplant critically ill patients supported by ECMO: a single-center study

OBJECTIVES: Infection is one of the important causes of death in intensive care unit (ICU) patients. At present, there are few articles focused on the detailed analysis of pathogenic microorganisms detected in different therapy periods of critically ill patients supported by extracorporeal membrane oxygenation (ECMO). METHODS: From October 2020 to October 2022, ECMO-assisted patients who underwent multiple times of both metagenomic next-generation sequencing (mNGS) test and conventional culture were enrolled continuously in the First Affiliated Hospital of Zhengzhou University. The baseline data, laboratory test results, and pathogenic microorganisms detected by mNGS and traditional culture in different time periods were recorded and analyzed. RESULTS: In the present study, 62 patients were included finally. According to whether the patients survived at discharge, they were divided into the survivor group (n = 24) and the non-survivor group (n = 38). Then, according to the different types of ECMO support, they were divided into the veno-venous ECMO (VV ECMO) group (n = 43) and the veno-arterial ECMO (VA ECMO) group (n = 19). The summit period of specimens of traditional culture and mNGS detection of ECMO patients was 7 days after admission, and the largest number of specimens of surviving patients appeared after ECMO withdrawal. The total number of traditional culture specimens was 1,249, the positive rate was 30.4% (380/1,249), and the positive rate of mNGS was 79.6% (82/103). A total of 28 kinds of pathogenic microorganisms were cultured from conventional culture, and 58 kinds of pathogenic microorganisms were detected by mNGS, including Mycobacterium, Rickettsia, and Chlamydia psittaci. In conventional culture, the most frequent Gram-negative bacteria, Gram-positive bacteria, and fungi were Klebsiella pneumoniae, Corynebacterium striatum, and Candida glabrata, and those with the highest frequency of occurrence in mNGS detection were Acinetobacter baumannii, Enterococcus faecium, and Aspergillus flavus. CONCLUSIONS: Throughout the whole treatment process, different kinds of suspicious biological specimens of high-infection-risk ICU patients supported by ECMO should undergo both mNGS detection and traditional culture early and repeatedly.