Analysis of Porcine Model of Fecal-Induced Peritonitis Reveals the Tropism of Blood Microbiome

Abstract

Recent studies have suggested the existence of a blood microbiome in the healthy host. However, changes in the blood microbiome upon bloodstream infection are not known. Here, we analyzed the dynamics of the blood microbiome in a porcine model of polymicrobial bacteremia induced by fecal peritonitis. Surprisingly, we detected bacterial populations in the bloodstream even before the infection, and these populations were maintained over time. The native blood microbiome was notably taxonomically different from the fecal microbiome that was used to induce peritonitis, reflecting microbial tropism for the blood. Although the population composition after the infection was similar to that of the native blood microbiome, new bacterial strains entered the bloodstream upon peritonitis induction as clinical symptoms relevant to sepsis developed. This indicates that the bacteria detected in the blood before peritonitis induction were derived from the blood rather than a contamination. Comparison of the functional pathways enriched in the blood and fecal microbiomes revealed that communication and stress management pathways are essential for the survival of the blood microbiome.

Lacticaseibacillus rhamnosus dfa1 Attenuate Cecal Ligation-Induced Systemic Inflammation through the Interference in Gut Dysbiosis, Leaky Gut, and Enterocytic Cell Energy

“…With a presence of intra-abdominal necrotic tissue in this model, the inflammation in the peritoneal cavity affects the balance of gut microbiota, despite the inflammatory lesions being walled off. Although these data are similar to the dysbiosis in several peritonitis models, such as spontaneous bacterial peritonitis, fecal peritonitis, and peritonitis in peritoneal dialysis [ 62 , 63 , 64 ], the dysbiosis in these situations might not be only from peritonitis alone but also from the underlying overt systemic responses, including cirrhosis, sepsis, and uremia, in these situations that might affect the gut dysbiosis. Here, despite the subtle systemic responses in the cecal ligation model, the alteration in fecal dysbiosis was prominent, supporting a vulnerability of the balance in microbiota in the gut to the microenvironment [ 65 ].…”

Insights into the circulating microbiome of Atlantic and Greenland halibut populations: the role of species-specific and environmental factors

“…The utility of this approach has recently been demonstrated in clinical settings, offering a new perspective for the development of biomarkers in ecology 21 – 24 similar to those described for several diseases in humans 16 , 20 , 25 . In fact, the existence of a blood microbiome is a concept that is now widely accepted in humans and animals, including pigs, broiler chickens, camels, cows, goats, cats and dogs 21 , 23 , 24 , 26 – 29 .…”

The Blood Microbiome and Health: Current Evidence, Controversies, and Challenges

“…In terms of inflammatory diseases, Hyun et al (2021) used a faeces-induced peritonitis porcine model and revealed the emergence of new circulating bacteria after disease induction, including Escherichia/Shigella , Staphylococcus , Cloacibacterium , Diaphorobacter and Rhodanobacter [ 60 ]. Functionally, these enriched bacteria are related to ABC transporters, oxidative phosphorylation, and two-component systems [ 60 ], which may aid in the pathogenesis of peritonitis.…”

“…In terms of inflammatory diseases, Hyun et al (2021) used a faeces-induced peritonitis porcine model and revealed the emergence of new circulating bacteria after disease induction, including Escherichia/Shigella , Staphylococcus , Cloacibacterium , Diaphorobacter and Rhodanobacter [ 60 ]. Functionally, these enriched bacteria are related to ABC transporters, oxidative phosphorylation, and two-component systems [ 60 ], which may aid in the pathogenesis of peritonitis. Interestingly, circulating levels of the genera Escherichia/Shigella and Staphylococcus were also significantly elevated in inflammatory bowel disease (IBD, comprising ulcerative colitis and Crohn’s disease) despite the unremarkable difference in the overall blood microbiome profiles between IBD and healthy individuals [ 61 ].…”