SouthernWorldwide.com – A recent study has uncovered a significant factor within the gut that could predispose certain individuals to developing sepsis, a potentially life-threatening condition.
Researchers from the Korea Research Institute of Bioscience and Biotechnology’s Infectious Disease Research Center conducted an investigation using female mice to understand the wide variations in sepsis outcomes among patients.
The study, detailed in the journal Nature, focused on genetically similar mice that exhibited different gut microbiome compositions. These mice were intentionally infected with Acinetobacter baumannii, a highly resistant bacterium known to cause sepsis.
The research team meticulously compared groups of mice, categorizing them by higher and lower survival rates. Their analysis involved examining disparities in their gut microbiomes, the quantity of bacteria present in their blood and organs, and various other cellular markers, as stated in the study’s press release.
Remarkably, even among genetically alike mice, those more susceptible to severe outcomes showed a greater concentration of Muribaculaceae bacteria in their gut. In one specific comparison, these bacteria constituted approximately 28% of the microbiome in mice with poor survival, in stark contrast to just 0.15% in those that survived better.
Mice exhibiting worse survival rates displayed an early and pronounced inflammatory response. This heightened inflammation subsequently led to a higher presence of bacteria in their blood, lungs, and spleen. According to the researchers, this indicates that the gut microbiome plays a role in making the immune system overly reactive.
Further observations within the gut microbiome of mice with poorer survival revealed the prominence of a specific bacterial strain, Sangeribacter muris KT1-3. When mice that typically had high survival rates were housed with mice carrying this KTI-3 strain, their survival rate plummeted to a mere 10%.
This particular bacterial strain also appeared to exacerbate inflammation during specific types of infections, thereby intensifying the severity of sepsis.
These findings strongly suggest that the gut microbiome can preemptively signal how the immune system is likely to respond even before an infection takes hold.
Dr. Andrew Fleming, section chief of Infectious Diseases & Immunology at NYU Langone Hospital, Brooklyn, noted that it has been a long-standing understanding that gut bacteria and their toxins can enter the bloodstream during sepsis.
This process, according to Dr. Fleming, who was not involved in the study, intensifies the inflammatory response to the initial infection.
“This process is particularly important in septic shock, where the intestinal wall becomes more permeable to translocation (or leaking) of bacterial products,” Fleming explained.
The intricate interactions between the gut microbiome and the immune system are characterized as “complex and variable from person to person,” the doctor elaborated.
“But there is mounting evidence that a diverse and healthy gut microbiome – the community of bacteria that lives in a person’s gut – is protective in some ways against severe sepsis,” he continued. “And a dysregulated microbiome – for example, one severely altered by antibiotics – can impair or worsen the immune system’s response during sepsis.”
Scientists are increasingly viewing the gut microbiome as akin to “a living organ,” Dr. Fleming stated, drawing parallels to vital organs like the heart, kidneys, or liver, all of which contribute to maintaining overall bodily health through their diverse functions.
An unhealthy microbiome can have “detrimental effects across a range of health issues,” he further emphasized, including a significant impact on how the body combats infections.
“Compared to our other organs, we currently have fewer readily available tests in the doctor’s office to measure the health of our microbiome,” Fleming observed. “However, this should not prevent us from thinking about our gut microbiome and how to keep it healthy.”
The use of antibiotics can lead to “major and long-lasting effects” on the microbiome, Dr. Fleming pointed out. He cited statistics from the CDC indicating that up to 80% of adults in the U.S. receive an antibiotic prescription annually, with an estimated 30% of these being unnecessary.
“We must begin to think much more critically about our antibiotic use and overuse, both to maintain our gut health and to reduce the spread of antibiotic resistance.”
While acknowledging the study’s findings as an “intriguing starting point for further research,” Dr. Fleming also highlighted some key limitations.
“Sangeribacter muris is not typically found in humans, so the exact mechanism of this bacterial strain worsening sepsis that is demonstrated in this study cannot be directly extrapolated to people,” he clarified. “Well-designed clinical trials should be conducted to explore how similar gut microbiome effects may play out in sepsis in humans.”
Despite these limitations, Dr. Fleming expressed support for the hypothesis that cultivating and maintaining a healthy gut microbiome can contribute to a well-regulated immune system, thereby potentially reducing the risk of developing severe sepsis.
