Intestinal dysbiosis, which occurs when the intestinal flora is unbalanced, is associated with mortality in the context of organ transplantation.
- When the intestinal flora is unbalanced, we speak of dysbiosis.
- Gut dysbiosis is linked to a high risk of death after transplantation, regardless of the organ received.
- Dutch researchers identified 23 bacterial species in recipients that were associated with a higher or lower risk of death from all causes.
The composition of the gut microbiome is associated with a variety of diseases, including inflammatory bowel disease and diabetes. But little research has the data needed to analyze the link between gut dysbiosis—an imbalance or poor microbial adaptation of the gut microbiota—and all-cause mortality in organ transplant recipients. That’s why researchers at the University Medical Center Groningen in the Netherlands decided to conduct a study published in the journal Good.
162 organ recipients died
In this work, the team analyzed the microbiome profiles of 1,337 fecal samples provided by 766 kidney transplant recipients, 334 adult liver transplant recipients, 170 lung transplant volunteers, and 67 heart transplant recipients. On average, the participants, who were generally over 57 years old, had received their transplant about seven years previously. The researchers then compared them to the gut microbiome profiles of 8,208 people living in the same geographic area in the northern Netherlands. During the follow-up period of up to 6.5 years, 162 recipients died. In detail: 88 kidney recipients, 33 liver recipients, 35 lung recipients, and six heart recipients. According to the data, 48 died of infection, 38 of cardiovascular disease, 38 of cancer, and 40 of other causes.
Imbalanced gut flora linked to increased risk of death after organ transplant
After this observation, the authors examined several indicators of gut dysbiosis in these samples: microbial diversity, the extent to which their gut microbiotas differed from the microbiota of the general population, the prevalence of antibiotic resistance genes, and virulence factors that help bacteria invade cells and evade immune defenses. According to the results, the more the characteristics of the gut microbiota of transplant recipients differed from those of the general population, the more likely they were to die quickly after surgery, regardless of the organ received. “Similar correlations emerged for the abundance of antibiotic resistance genes and virulence factors.”
23 bacterial species associated with all-cause mortality
The analysis also identified 23 bacterial species in all transplant recipients that were associated with a higher or lower risk of death from all causes. “For example, an abundance of four Clostridium species was associated with death from all causes and specifically from infection, while an abundance of Hangatella Hathewayi and Veillonella parvula was associated with death from all causes and specifically from infection. High numbers of Ruminococcus gnavus, but low numbers of Germigger formicilis, Firmicutes bacterium CAG 83, Eubacterium hallii, and Faecalibacterium prausnitzi were associated with death from all causes, and specifically from cancer,” explained the scientists.
