Slackia

Slackia is a genus of bacteria in the family Coriobacteriaceae, within the phylum Actinobacteria. Members are Gram-positive, strictly anaerobic, non-spore-forming bacteria that are typically rod-shaped or pleomorphic. They are commonly isolated from the gastrointestinal tracts of humans and other animals and are considered part of the gut microbiota; some species have also been found in environmental samples.

Taxonomically, Slackia belongs to the domain Bacteria, phylum Actinobacteria, class Coriobacteriia, order Coriobacteriales, and family Coriobacteriaceae. The genus comprises several species described from mammalian gastrointestinal sources, with varying degrees of metabolic specialization.

Metabolism and notable species: Slackia species are generally heterotrophic and fermentative. Notable described species include Slackia isoflavonivorans, which can convert dietary isoflavones such as daidzein to equol, a metabolite with estrogenic activity. Another described species, Slackia heliotrinireducens, is known for reducing heliotrin in culture. Additional described Slackia species have been isolated from animal feces or gut material, reflecting a gut-associated lifestyle.

Clinical and ecological significance: There are no well-established associations with human disease for Slackia, and the genus is primarily of interest to microbiologists studying gut ecosystems and the metabolism of dietary polyphenols and other compounds. Genomic studies of Slackia species have begun to shed light on anaerobic metabolism and secondary metabolite processing within the Coriobacteriaceae.