Circulating Microbial Cell-Free DNA in Health and Disease

Human blood contains low biomass of circulating microbial cell-free DNA (cfmDNA) that predominantly originates from bacteria. Numerous studies have detected circulating cfmDNA in patients with infectious and non-infectious diseases, and in healthy individuals. Remarkable differences were found in the microbial composition of healthy subjects and patients compared to cohorts with various diseases or even patients with diversified prognoses, implying that these alterations may be associated with disease development. Although the function of circulating cfmDNA needs to be elucidated (whether it acts as a bystander of dysbiosis or a key player in disease development), several studies have demonstrated its potential as a non-invasive biomarker that may improve diagnosis and treatment efficacy. The origin of circulating cfmDNA is still the subject of much deliberation, but studies have identified members of various microbiome niches, including the gut, oral cavity, airways, and skin. Further studies investigating the origin and function of circulating cfmDNA are needed. Moreover, low-biomass microbiome studies are prone to contamination, therefore stringent negative experimental control reactions and decontamination frameworks are advised in order to detect genuine circulating cfmDNA.

Automated summary

Human blood contains low biomass of circulating microbial cell-free DNA (cfmDNA) that primarily comes from bacteria. Circulating cfmDNA has been detected in patients with various diseases and in healthy individuals. Differences in microbial composition between healthy individuals and patients suggest potential associations with disease development. Although the function of circulating cfmDNA needs further clarification, it has the potential to serve as a non-invasive biomarker for improved diagnosis and treatment efficacy. The origin and function of circulating cfmDNA require further investigation.