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BACKGROUND: An increasing number of critically ill patients are immunocompromised. These patients are at high risk of intensive care unit (ICU) admission because of numerous complications. Acute respiratory failure due to severe community-acquired pneumonia (SCAP) is one of the leading causes of admission. Early targeted antibiotic therapy is crucial for improving the prognosis of these patients. Metagenomic next-generation sequencing (mNGS) in bronchoalveolar lavage fluid (BALF) has shown significant value in pathogen detection in recent years. However, there are few studies on summarizing pathogen profiles of SCAP in immunocompromised patients. METHODS: We performed a multicenter retrospective analysis of patients with SCAP in the ICU diagnosed between May 2021 to October 2024. Bronchoalveolar lavage fluid (BALF), blood, and sputum samples were collected and subjected to mNGS and conventional microbiological tests (CMTs). The pathogen profiles detected by the two methods were compared. RESULTS: In our study, compared to CMTs, mNGS increased the detection rates of mixed infections in the immunocompromised group (58.82% vs 17.96%, P < 0.05) and immunocompetent group (44.58% vs 18.72%, P < 0.05), while also reducing the rate of no pathogen detected (4.90% vs 38.73%, P < 0.05; 8.37% vs 32.76%, P < 0.05). In both groups, the proportion of positive clinical impacts (diagnosis) resulting from mNGS results exceeded 90% (96.57% vs 93.84%), and the treatment effectiveness rate in the immunocompromised group was higher than in the immunocompetent group (65.69% vs 56.40%, P < 0.05). Further analysis showed that when mNGS-guided treatment was effective, the 28-day mortality rate significantly improved in both the immunocompromised group (31.34% vs 74.29%, P < 0.05) and the immunocompetent group (42.36% vs 40.68%, P < 0.05) compared to when the treatment was ineffective. CONCLUSION: This study indicates that ICU patients with SCAP, particularly those who are immunocompromised, are more likely to have polymicrobial infections. mNGS in BALF provides rapid and comprehensive pathogen profiling of pulmonary infections, thereby having a positive impact on both the diagnosis, treatment and prognosis of immunocompromised patients with SCAP.
Zhao et al. (Wed,) studied this question.