Eubiotic vs. dysbiotic human blood microbiota: the phenomenon of cell wall deficiency and disease-trigger potential of bacterial and fungal L-forms.

The current review provides data and focuses on blood as a niche for the presence of cell wall-deficient microbes (L-forms). The hypothesis for the existence of L-form microbiota in humans was tested by us using an innovative methodology for the isolation of L-form cultures from human blood. Criteria were conceived for the individual assessment of blood microbiota and recognition of two types of states -- "eubiotic" and "dysbiotic" blood microbiota. Cell wall-deficient microbes (CWD) that inhabit blood in healthy people are in natural balance with the host homeostasis, which corresponds to the "eubiotic" state. When interacting with a host, CWD bacteria or fungi employ a strategy distinctive for a latent lifestyle. In contrast to "eubiotic," "dysbiotic" blood microbiota manifests when the balance is disrupted and there is an excess of L-form variants of opportunistic microbes that invade from the external microbiota, i.e., from all body sites in contact with the external environment. Our case studies on people with multiple sclerosis (MS), Parkinson's disease, psoriasis, thyroid cancer, and diabetes revealed the appearance of "dysbiotic" blood microbiota that outlined the disease-trigger potential of opportunistic bacteria and fungi existing in blood as CWD variants. Blood microbiota assessment could be of diagnostic and prognostic importance for the pathological processes occurring within the body, as well as for understanding the microbial pathogenesis.