This is an interesting topic that I think about sometimes. It gets a lot of coverage on some more conspiracy-sided websites because it gives some credence to their pet-theory that all cancers are really fungi or something. That seems like nonsense to me. But this is an interesting subject anyway, one that might influence what supplements we take and so on.
In general, I'm always interested in those things we don't know, looking back at health 25 years from now will be interesting as more and more is uncovered (nanobacteria etc).
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.
CONCLUDING REMARKS AND PROSPECTIVE EXPERIMENTS‘Non-culturable’ (which should be called ‘not-easily-culturable’ or ‘not-yet-cultured’) microbes are commonplace in the ‘environmental microbiology’ of soil and water, and the blood certainly represents an ‘environment’. As we show here, there is a large and scattered literature, increasing in size, to the effect that there might be a (mainly dormant) microbial component in a variety of chronic diseases that are normally considered to be non-microbial or non-communicable in nature, even when microbes appear absent by culturability criteria. Our previous work (e.g. Bester et al. 2013; Pretorius et al. 2013, 2014a; Kell and Pretorius 2014, 2015; Pretorius and Kell 2014) has implied iron dysregulation as a regular accompaniment to, and probable contributory factor for, a variety of similar diseases, all of which have an inflammatory component. We argue here that there is also a microbial contribution to this in the blood, and it is not unreasonable that the microbial requirement for iron means that, despite the oxidative stress it can entail (Touati 2000; Kell 2009, 2010), microbes may be anticipated to increase in prevalence when iron is free (e.g. Ratledge 2007; Clifton, Corrent and Strong 2009; Sia, Allred and Raymond 2013; Chu et al. 2014) and available (D'Onofrio et al. 2010), probably behaving in a social manner (Kell, Kaprelyants and Grafen 1995; West and Buckling 2003; Diggle et al. 2007; Harrison and Buckling 2009).
We have here pointed up the likelihood of a steady crop of effectively dormant microbes being a feature of blood biology in chronically diseased humans, including those with non-communicable diseases. As with any complex system, the magnitude of any component is affected by the kinetics of every relevant step; while the precise nature of all the interactions is uncertain, Fig. 8 describes the general network—the first step in any systems analysis (Kell 2006; Kell and Knowles 2006).
Figure 8.Relationships between a dormant blood microbiome and chronic disease dyamics.
Consequently, we recognize that the analysis above has largely been qualitative (the ‘presence’ of a microbial component in a specific disease is a qualitative statement). However, chronic, non-communicable diseases are very far from being static (and thousands of human genes change their expression at least 2-fold even on a diurnal basis; Zhang et al. 2014b). Thus, a clear further issue is to seek to understand how the blood microbiome may co-vary with the day-to-day dynamics of chronic diseases. For example, rheumatoid arthritis has circadian rhythms (Straub and Cutolo 2007) and is well known to provide significant variations (‘flares’; Flurey et al. 2014) in severity at different times. A reasonable strategy is thus to look for changes in a detectable blood microbiome in this and other diseases that show such flares. As with H. pylori and stomach ulcers (and cancer), the simple prediction is that bactericidal antibiotics should be of value in the treatment of such supposedly non-communicable diseases. Indeed, this prediction is borne out for diseases such as rheumatoid arthritis (Ogrendik 2009a, 2013a; Kwiatkowska and Maślińska 2012) and multiple sclerosis (Ochoa-Repáraz et al. 2009; 2011), while antipneumococcal vaccination has shown efficacy in preventing stroke (Vila-Corcoles et al. 2014). Of course, events such as heart attacks and strokes (and see Table 4) may also be seen as sudden increases in severity of an underlying condition, and in some cases (such as the much increased likelihood of strokes after subarachnoid haemorrhages; McMahon et al. 2013), analysis of changes in the blood microbiome might prove predictive.
The obvious next tasks are thus to relate the number and nature of blood microbes observed in cases such as the above to microbial sequences and antigens that can be detected in aliquots of the same samples (e.g. Salipante et al. 2013, 2015), to determine the physiological state of the various microbes (including e.g. whether they are L-forms), and to establish methods to bring them (back) into culture. Since microbes, inflammation and various syndromes are such common co-occurrences (as are coagulopathies; Kell and Pretorius 2015), longitudinal studies will have a specially important role, as they will both show the dynamics and be able to help discriminate cause and effect during the time evolution of chronic, non-communicable diseases in ageing populations. The immunogenicity of persisters, and their ability to induce various kinds of inflammation, must be rather different from that of replicating organisms, and this must be investigated. Armed with such collective knowledge, we might be better placed to develop therapeutics such as pre- and probiotics and bactericidal antibiotics for use in such cases previously thought to lack a microbial contribution.
http://femsre.oxford...sre.fuv013.full