Composition and diversity of the pulmonary microbiome in acute respiratory distress syndrome: a systematic review.

The pulmonary microbiome plays a crucial role in respiratory health and disease, with growing evidence suggesting its involvement in the pathophysiology of acute respiratory distress syndrome (ARDS). This systematic review synthesises current findings on primarily the composition of the lung microbiome in ARDS patients, and secondarily evaluates the microbial diversity, bacterial abundance and their potential clinical implications on disease severity, ventilator-free days and mortality. A comprehensive literature search identified 11 studies, including 660 patients, 466 of whom had ARDS, examining lung microbial alterations in ARDS using different sequencing technologies. While studies reported different, but consistent changes in microbial compositions, findings on diversity varied across studies. Trends suggest an increased prevalence of specific opportunistic pathogens, particularly members of the gut-associated Enterobacteriaceae family, which was also shown to be associated with fewer ventilator-free days and mortality, although differences in patient populations, study methodologies, and sequencing techniques influenced the results. The relationship between the pulmonary microbiome and clinical outcomes, remains an area of active investigation. Clinical trial Registration:the PROSPERO ID CRD42023467660.