Bacterial symbiont networks. a, Computed SparCC co-occurrence networks for all samples containing at least two microbe species after decontamination at different SparCC association thresholds (0.05, 0.2, 0.3). Only correlations with a SparCC correlation size greater than the respective thresholds are retained. b, SparCC networks for individual cohorts at a correlation threshold of 0.2. Co-occurrence associations were not preserved after taking the intersection of edges between all ensemble networks. In a and b, each node represents a single microbial species, and each edge represents a single association between a pair of microbial species. Edge thickness is measured by link size. The number of samples used to calculate each network and the correlation limits used are explained. Positive and negative SparCC correlation is indicated in green and blue, respectively. credit: Nature Microbiology (2023). DOI: 10.1038/s41564-023-01350-w
No stable microbial community resides in the bloodstream of healthy humans, according to a new study led by a UCLA researcher.
the new Nature Microbiology The paper makes an important confirmation that blood donation is an important part of medical practice. Understanding the types of microbes that can be found in blood may allow the development of better microbial tests in blood donations, reducing the risk of transfusion-related infections.
Lead author, Ph.D. “Human blood in general is considered sterile,” said student Cedric Tan (UCLA Institute of Genetics and Francis Crick Institute. And while sometimes microorganisms enter the bloodstream such as from a wound or after brushing the teeth, this quickly resolves by the immune system.
“But in recent decades, this model has been challenged by speculation that blood can host a community of microbes. Here, we confirmed that this is not the case, because most people’s blood does not contain microbes, and the types of microbes found in some people’s blood vary greatly.” Between individuals “.
For the study, Cedric worked with a team led by Dr. Niranjan Nagarajan at A*STAR’s Genome Institute in Singapore to analyze population-level sequencing data from “SG10K Health,” a project of Singapore’s National Precision Medicine Program.
After accounting for pervasive contamination in microbiome probes, the team found that microbes were only detected rarely and sporadically in the blood, rather than existing as stable communities. Of their sample of 9,770 people, 84% of people had no microbes in their blood sample, and less than 5% of people shared the same type.
The scientists also found evidence that some bacteria in the blood of healthy individuals may multiply and that most of these bacteria are normally found in the human intestine, mouth, or skin. Their findings indicate that microbes sometimes enter the bloodstream from other body sites without causing disease, but that there is no core group of species that colonize the blood of healthy individuals.
The results also provide a useful resource for the types of microbes one might expect to occasionally see in the blood of healthy humans. Characterization of the range of microbial species present in the blood of healthy individuals forms a crucial basis for comparison with infected individuals, shedding light on how blood microbial profiles relate to health status.
In a research brief accompanying the study, Cedric wrote: “Our study focuses on healthy individuals but does not preclude the presence of blood microbial communities in patients with chronic diseases such as cancer or diabetes. The next logical step would be to determine if blood-transmitted communities are present.” In these cases and if the communities mentioned are associated with disease severity and progression.This approach may open new doors for microbiome-based therapies for chronic diseases.”
more information:
Cedric CS Tan et al, No evidence of a common blood microbiome based on a population-based study of 9,770 healthy humans, Nature Microbiology (2023). DOI: 10.1038/s41564-023-01350-w
There is no microbial community in the blood of healthy individuals, Nature Microbiology (2023). DOI: 10.1038/s41564-023-01364-4
the quote: Study Finds No Evidence for Common Blood Microbes in Healthy Humans (2023, April 5) Retrieved April 5, 2023 from https://phys.org/news/2023-04-evidence-common-blood-microbes-healthy. html
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