Diagnostic Value and Clinical Application of Metagenomic Next-Generation Sequencing for Infections in Critically Ill Patients.

Objective: To evaluate the diagnostic value and clinical application of metagenomic next-generation sequencing (mNGS) for infections in critically ill patients. Methods: Comparison of diagnostic performance of mNGS and conventional microbiological testing for pathogens was analyzed in 234 patients. The differences between immunocompetent and immunocompromised individuals in mNGS-guided anti-infective treatment adjustment were also analyzed. Results: The sensitivity and specificity of mNGS for bacterial and fungal detection were 96.6% (95% confidence interval [CI], 93.5%-99.6%) and 83.1% (95% CI, 75.2%-91.1%), and 85.7% (95% CI, 71.9%-99.5%) and 93.2% (95% CI, 89.7%-96.7%), respectively. Overall, 152 viruses were detected by mNGS, but in which 28 viruses were considered causative agents. The proportion of mNGS-guided beneficial anti-infective therapy adjustments in the immunocompromised group was greater than in the immunocompetent group (48.5% vs 30.1%; P=0.008). In addition, mNGS-guided anti-infective regimens with peripheral blood and BALF specimens had the highest proportion (39.0%; 40.0%), but the proportion of patients not helpful due to peripheral blood mNGS was also as high as 22.0%. Conclusion: mNGS might be a promising technology to provide precision medicine for critically ill patients with infection.

Comparison of endotracheal aspirate and bronchoalveolar lavage fluid metagenomic next-generation sequencing in severe pneumonia: a nested, matched case-control study.

OBJECTIVES: To compare clinical outcomes in patients with severe pneumonia according to the diagnostic strategy used. METHODS: In this retrospective, nested, case-control study, patients with severe pneumonia who had undergone endotracheal aspirate (ETA) metagenomic next-generation sequencing of (mNGS) testing (n = 53) were matched at a ratio of 1 to 2 (n = 106) by sex, age, underlying diseases, immune status, disease severity scores, and type of pneumonia with patients who had undergone bronchoalveolar lavage fluid (BALF) mNGS. The microbiological characteristics and patient's prognosis of the two groups were compared. RESULTS: An overall comparison between the two groups showed no significant differences in bacterial, fungal, viral, or mixed infections. However, subgroup analysis of 18 patients who received paired ETA and BALF mNGS showed a complete agreement rate for the two specimens of 33.3%. There were more cases for whom targeted treatment was initiated (36.79% vs. 22.64%; P = 0.043) and fewer cases who received no clinical benefit after mNGS (5.66% vs. 15.09%; P = 0.048) in the BALF group. The pneumonia improvement rate in the BALF group was significantly higher than in the ETA group (73.58% vs. 87.74%, P = 0.024). However, there were no significant differences in ICU mortality or 28-day mortality. CONCLUSIONS: We do not recommend using ETA mNGS as the first-choice method for analyzing airway pathogenic specimens from severe pneumonia patients.