In the work of clinical medicine diagnosis and treatment, pathogen detection plays a crucial role. Traditional detection methods mainly include smear microscopy, isolation culture, and immunoserological tests. In recent years, with the development of technologies such as nucleic acid amplification and sequencing, molecular biology techniques have further improved pathogen diagnostic rates and positive detection rates. These technologies can make more contributions to pathogen detection, analysis of pathogenicity and drug resistance, epidemiological investigations, and hospital infection prevention and control.
Traditional pathogen detection methods are relatively simple to operate, but they can only cover a limited variety of pathogens. The detection cycle is long and the steps are cumbersome, highly dependent on manual experience and operation, resulting in low overall detection efficiency. Moreover, the continuous increase in bacterial resistance poses certain difficulties for microbiological diagnosis. With China's continuous investment in the construction of the infectious disease prevention and control system and basic capabilities, microbiological detection technology is developing rapidly. Since the 1980s, the microbiological detection industry has entered a stage of rapid development and has become a key focus of the industry's development.
According to the experimental data from Professor Zhao Hongqing's team at Wuxi Second People's Hospital Affiliated to Nanjing Medical University, which included 140 hospitalized patients suspected of having pulmonary infections, mNGS had a higher detection rate than conventional laboratory diagnostic methods in total positive cases, with its sensitivity (89.17%) significantly higher than that of conventional testing (50.00%). Therefore,mNGS technologyBy enabling direct, non-discriminatory, and high-throughput sequencing of samples without the need for pathogen isolation, culture, or amplification, it has developed a wide coverage, non-targeted, high-throughput, and highly sensitive characteristic. This has shortened detection time and improved efficiency, making it a new trend in pathogen detection in recent years.
mNGS refers to metagenomic second-generation sequencing technology, which does not rely on traditional microbial culture. It can directly extract all nucleic acids from specimens for high-throughput sequencing. By analyzing biological information and removing human-derived sequences, the screened data can bePathogen databaseBy comparison, the species and genus information of suspected pathogenic microorganisms were obtained. The detection process of mNGS covers specimen collection, nucleic acid extraction, library construction, sequencing on a machine, bioinformatics analysis, and report interpretation stages. Among these, specimen quality, relative and absolute abundance of microorganisms, as well as the integrity and bias-free nature of the database, have a significant impact on mNGS detection results. Therefore, nucleic acid extraction, library construction, and bioinformatics analysis are crucial quality control steps throughout the process.
