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.