TLR4 and serum lipopolysaccharide activity: The overgrowth of these strains will send several stress signals to the host, for instance, through microorganism or pathogen-associated molecular patterns that activate the host pattern-recognition receptors [42] and through bacterial specific molecules like Gram-negative lipopolysaccharides (LPS), typical of proteobacterial outer membranes, that are well known for triggering an immune response after being absorbed via the formation of chylomicrons [43], stimulating a TLR4-CD14–dependent proinflammatory response and producing endotoxemia [2, 44].