A human-derived Bacteroides strain attenuates depressive-like behavior in a rat model of social defeat-induced stress

The gut microbiome has been linked to mood disorders via communication along the gut-brain axis. We previously found levels of fecal Bacteroides were inversely associated with brain signatures of depression in the prefrontal cortex of human subjects. Bacteroides are important human commensals, playing a keystone role in regulating the immune system and producing bioactive metabolites, like the neurotransmitter gamma-aminobutyric acid and vitamin B12.Methods: To better understand the link between Bacteroides and depression -- and test a candidate novel next-generation probiotic -- we administered a human-derived gut microbial strain orally in rats that were subjected to the repeated social defeat model of stress-induced depression. The fecal microbiome and the prefrontal cortex transcriptome were then profiled for intervention-induced alterations.