Deciphering the dynamics of blood microbiome: Influence of physiological conditions and correlations with mucosal microbiota

Babayev H., Satıtsuksanoa P., Celebı Sozener Z., Pat Y., Yazıcı D., Ardıçlı S., ...More

World Immune Regulation Meeting XVIII 2024, Chur, Switzerland, 13 - 16 March 2024, vol.18, no.12, pp.56

  • Publication Type: Conference Paper / Summary Text
  • Volume: 18
  • City: Chur
  • Country: Switzerland
  • Page Numbers: pp.56
  • Bursa Uludag University Affiliated: Yes


Damage to the integrity of epithelial barriers, particularly in the gut and respiratory tracts, can lead to increased permeability, allowing microbial translocation into the bloodstream. This study aims to elucidate the dynamics of the blood microbiome associated with epithelial barrier damage and assess the influence of physiological conditions. Blood samples were separated into buffy-coat, plasma, red blood cells (RBCs), peripheral blood mononuclear cells (PBMC), and polymorphonuclear-leukocytes (PMNs) to measure bacterial DNA and understand microbial translocation. Next-generation sequencing was employed to analyze the blood microbiome of participants with varying levels of epithelial barrier integrity, including healthy individuals and those with obesity, known for weakened barrier function and dysbiosis. Our analysis revealed that the buffy-coat contained 89.77% of the total circulating bacterial DNA, underscoring its role in immune defense and pathogen capture. Surprisingly, RBCs harbored 10.2% of the circulating bacterial DNA, indicating a previously unexplored pathway for microbiome interaction. In contrast, plasma contained negligible bacterial DNA, reinforcing its role primarily as a transport medium. 29.36% of the bacterial DNA in the buffy coat was found in PBMCs and 70.64% in PMNs. Comparative microbial profiling of individuals with varying epithelial barrier integrity showed a marked prevalence of Burkholderiaceae, Propionibacteriaceae, and Alcaligenaceae, with notable fluctuations between samples. Our findings substantiate the hypothesis that epithelial barrier damage facilitates microbial translocation into the bloodstream, leading to distinct alterations in microbial DNA in the blood. Notably, the buffy-coat emerged as a primary site for bacterial DNA, suggesting its significant role in immune response and pathogen capture. The presence of bacterial DNA in RBCs introduces a novel avenue for microbiome-blood interactions, previously underexplored. Furthermore, the negligible amount of bacterial DNA found in plasma underscores its potential as a practical marker for assessing microbial translocation and epithelial barrier integrity, offering a less invasive means to monitor health and disease states.