SOURCE:www.massgeneralbrigham.org
The man, a retired US Marine officer in his 60s, started experiencing odd symptoms after taking multiple courses of antibiotics to treat an inflamed prostate. He had been fit and healthy, and had only an occasional alcoholic drink, but he suddenly began feeling very drunk, disoriented and sleepy on a regular basis.
Researchers Search for Why Some People’s Gut Microbes Produce High Alcohol Levels
Researchers have identified specific gut bacteria and metabolic pathways that drive alcohol production in patients with auto-brewery syndrome (ABS), a rare and often misunderstood condition in which people experience intoxication without drinking alcohol. The research team from Mass General Brigham, in collaboration with colleagues at University of California San Diego, published their findings in Nature Microbiology.
ABS occurs when gut microbes break down carbohydrates and convert them to ethanol (alcohol) that enters the bloodstream. While carbohydrate metabolism can produce small amounts of alcohol in everyone, levels can be high enough to cause intoxication in people with ABS. The condition is extremely rare but likely underdiagnosed due to a lack of awareness, diagnostic challenges, and stigma.
Many patients experience years of misdiagnosis and social, medical, and legal consequences before receiving a diagnosis. Confirmation of ABS is also difficult to obtain, as the gold-standard diagnosis requires monitored blood alcohol testing under supervised conditions.
To better understand the condition, researchers evaluated 22 patients with ABS, 21 unaffected household partners, and 22 healthy control participants. The team then compared gut microbial composition and function across groups.
The study showed that stool samples taken from patients during a flare of ABS produced significantly more ethanol in the lab than samples from household partners or healthy controls—pointing to the potential for a stool-based diagnostic test.
Previously, scientists had very little information about which specific gut microbes (yeasts or bacteria) caused ABS. The stool analysis pointed to several bacterial species as key drivers in patients including Escherichia coli and Klebsiella pneumoniae. In addition, during ABS flares, some patients had much higher levels of enzymes involved in fermentation pathways, compared to controls. While some patients had these organisms, the authors note that finding the causative microbes in individual patients is an arduous process.
Researchers also followed one patient who experienced symptom relief after undergoing a fecal microbiota transplantation when other treatments had failed. Relapse and remission corresponded with shifts in specific bacterial strains and metabolic pathway activity, providing further biological evidence for the condition. After a second fecal transplant, with different antibiotic pretreatment, the patient was symptom-free for more than 16 months.
“Auto-brewery syndrome is a misunderstood condition with few tests and treatments. Our study demonstrates the potential for fecal transplantation,” said co-senior author Elizabeth Hohmann, MD, of the Infectious Disease Division in the Mass General Brigham Department of Medicine. “More broadly, by determining the specific bacteria and microbial pathways responsible, our findings may lead the way toward easier diagnosis, better treatments, and an improved quality of life for individuals living with this rare condition.”
Hohmann is currently working with colleagues at UC San Diego on a study evaluating fecal transplantation in eight patients with ABS.
