To evaluate the clinical application value of metagenomic next-generation sequencing (mNGS) technology in the diagnosis of community-acquired pneumonia (CAP) pathogens.

A total of 345 inpatients who were clinically diagnosed with CAP and examined by mNGS and laboratory routine methods in the First Affiliated Hospital, Zhejiang University School of Medicine from February to August 2021 were retrospectively analyzed, and their clinical data were collected. The demographic characteristics, the results of mNGS and laboratory routine tests, the anti-infection regimen, and the levels of C-reactive protein (CRP) and procalcitonin (PCT) before and after regimen adjustment were recorded.

There were 173 positive patients tested by laboratory routine methods with 33 microorganisms, and 315 positive patients by mNGS with 130 microorganisms. The positive rate of mNGS was much higher than that of laboratory routine methods [91.30% (315/345) vs. 50.14% (173/345), χ² = 129.097, P < 0.001], with the consistency test Kappa = 0.105, P = 0.001. The positive rate of mNGS in the 294 patients exposed to antibiotics was also significantly higher than that of laboratory routine methods [90.48% (266/294) vs. 49.32% (145/294), χ² = 109.924, P < 0.001]. Meanwhile, there was a statistically significant difference in the diagnosis rate between mNGS and laboratory routine methods [85.22% (294/345) vs. 39.13% (135/345), χ² = 141.040, P < 0.001]. Compared with at admission, the levels of CRP [68 (24, 118) mg/L vs. 12 (5, 46) mg/L, Z = 6.154, P < 0.001] and PCT [0.53 (0.20, 0.93) μg/L vs. 0.25 (0.08, 0.54) μg/L, Z = 2.572, P = 0.010] in the patients with mNGS results as the basis for etiological diagnosis decreased markedly on the third day after adjusting the anti-infection regimen.

In the etiological detection of CAP patients, the mNGS technology has the advantages of less impact of previous antibiotic exposure and broader detection of pathogens, which can be a feasible supplementary means.