Chronic fatigue syndrome linked to gut bacteria

PanARMENIAN.Net - Scientists at the Center for Infection and Immunity (CII) at Columbia University's Mailman School of Public Health have discovered abnormal levels of specific gut bacteria related to chronic fatigue syndrome/myalgic encephalomyelitis, or ME/CFS, in patients with and without concurrent irritable bowel syndrome, or IBS.

Findings are published in the journal Microbiome.

The study is among the first to disentangle imbalances in the gut bacteria in individuals with ME/CFS and IBS. ME/CFS is a complex, debilitating disorder characterized by extreme fatigue after exertion and other symptoms including muscle and joint pain, cognitive dysfunction, sleep disturbance, and orthostatic intolerance. Up to 90 percent of ME/CFS patients also have IBS.

The researchers followed 50 patients and 50 matched healthy controls recruited at four ME/CFS clinical sites. They tested for bacterial species in fecal samples, and for immune molecules in blood samples.

They report:

• Levels of distinct intestinal bacterial species--Faecalibacterium, Roseburia, Dorea, Coprococcus, Clostridium, Ruminococcus, Coprobacillus--were strongly associated with ME/CFS; their combined relative abundance appeared to be predictive of diagnosis

• Increased abundance of unclassified Alistipes and decreased Faecalibacterium were the top biomarkers of ME/CFS with IBS; while increased unclassified Bacteroides abundance and decreased Bacteroides vulgatus were the top biomarkers of ME/CFS without IBS

• An analysis of bacterial metabolic pathways associated with disturbances in gut bacteria revealed distinct differences between ME/CFS and ME/CFS subgroups relative to healthy controls

• In ME/CFS subgroups, symptom severity measures, including pain and fatigue, correlated with the abundance of distinct bacterial types and metabolic pathways

• No changes were observed in immune markers--a finding that may reflect the dearth of participants who had been ill for a short time; earlier research suggests immune changes may only be evident when comparing short and long duration cases