The dormant blood microbiome in chronic, inflammatory diseases

Abstract

Blood in healthy organisms is seen as a ‘sterile’ environment: it lacks proliferating microbes. Dormant or not-immediately-culturable forms are not absent, however, as intracellular dormancy is well established. We highlight here that a great many pathogens can survive in blood and inside erythrocytes. ‘Non-culturability’, reflected by discrepancies between plate counts and total counts, is commonplace in environmental microbiology. It is overcome by improved culturing methods, and we asked how common this would be in blood. A number of recent, sequence-based and ultramicroscopic studies have uncovered an authentic blood microbiome in a number of non-communicable diseases. The chief origin of these microbes is the gut microbiome (especially when it shifts composition to a pathogenic state, known as ‘dysbiosis’). Another source is microbes translocated from the oral cavity. ‘Dysbiosis’ is also used to describe translocation of cells into blood or other tissues. To avoid ambiguity, we here use the term ‘atopobiosis’ for microbes that appear in places other than their normal location. Atopobiosis may contribute to the dynamics of a variety of inflammatory diseases. Overall, it seems that many more chronic, non-communicable, inflammatory diseases may have a microbial component than are presently considered, and may be treatable using bactericidal antibiotics or vaccines.

Rhamnolipids, Microbial Virulence Factors, in Alzheimer’s Disease

“…Overall, many diseases of chronic inflammation may be attributed to the presence of microbial components such as LPSs [1,15,70]. The continuous generation of bacterial components, considered as potent inflammatory agents, as well as their feedback from the pool of the dormant bacteria, may well justify the persistent, but mild-manifested inflammation, followed by inflammatory cytokine production, which is characteristic of many diseases [20].…”

“…The result of this symbiosis is the genesis of the collective genomes of these co-residing microorganisms, named microbiome, which in turn are determined by several factors of the host like hereditary and nutritional ones that possibly affecting host behavior in both healthy and diseased conditions [1]. Furthermore, microbes can survive on blood tissues or relocate in unusual places, a case well described by the Greek terms "dysbiosis: bad-bios (=bad+life)" or "atopobiosis: bios (=life) in other topos (=place+life)", respectively [1]. This situation may influence the evolution and dynamics of a variety of inflammatory diseases.…”

“…Microbes may arrange host nutrition and metabolism crucially affecting the evolvement and functionality of the immune system [1]. When the composition of the bacterial population is disturbed or modified, or when the host homeostasis becomes unbalanced under certain circumstances, these conditions may constitute causes for the host transition from a healthy situation to a pathogenic one.…”

Reproductive Microbiomes: Using the Microbiome as a Novel Diagnostic Tool for Endometriosis

“…Within the gut, it has been demonstrated that inflammatory bowel disease may result from altered interactions between the intestinal microbes and the mucosal immune system [22]. It is hypothesized that a variety of inflammatory diseases with unknown etiology, like rheumatoid arthritis, may be a result of microbes entering the blood from the gut or oral cavity and causing disease [23]. Further, early perturbations of the gut microbiota may result in chronic inflammation and metabolic disease [24].…”

The human microbiome, from Achilles armour to Nessus’ shirt

“…While for decades we could rest assured that the only microbially colonised niches seemed to be our digestive system and the skin, there is now hardly any part of our bodies indeed not inhabited by microbes. This includes nasal and auditory cavities, hair follicles and sweat glands, the respiratory and the urogenital tract systems and might even include dormant remainders of infections circulating in our blood system (Bassis et al 2015;Callewaert et al 2014;Costello et al 2009;Potgieter et al 2015;Thomas-White et al 2016). In short, apparently anything that can be reached and attached to in the human body becomes colonised by bacteria.…”