“…Results from these analyses converge on a microbiome dominated by Firmicutes, Actinobacteria, Proteobacteria, and Bacteroidetes phyla ( Table 1 ) [ 9 , 25 ], with less abundant Fusobacteriota [ 26 , 27 ]. Some genera belonging to the phylum Firmicutes were identified in blood: Bacillus , obliged aerobic bacteria widespread in nature; [ 9 , 26 , 28 , 29 ] Lactobacillus, facultative anaerobic able to convert lactose and other sugars in lactic acid by lactic fermentation; Streptococcus , facultative anaerobic able to produce hemolytic exotoxins such as streptolysin; and Romboutsia [ 30 ], a gut species isolated in humans [ 31 ]. Moreover, the Actinobacteria genus Corynebacterium , commensal human bacteria usually not pathogenic in healthy state; Proteobacteria genus Pseudomonas , bacteria with great metabolic diversity able to colonize a wide range of niches [ 9 ]; and Bacteroides , a Bacteroidota genus associated with the gut microbiome, able to process complex polysaccharides into simpler ones were detected in healthy blood [ 30 , 32 ].…”