This study investigated the potential of *Hafnia alvei*, a ClpB-producing commensal bacterium, as a probiotic for appetite and body weight management. Using *ob/ob* and high-fat diet (HFD)-fed obese mice, researchers found that chronic administration of *H. alvei* reduced body weight gain and fat mass, and decreased food intake in hyperphagic *ob/ob* mice. Elevated fat tissue levels of phosphorylated hormone-sensitive lipase were also observed. In silico analysis of human fecal metagenomes showed lower enterobacterial ClpB gene richness in obese individuals. These findings suggest *H. alvei* may be a useful probiotic for managing appetite and body weight.

Romain Legrand, Nicolas Lucas, Manon Dominique, Saida Azhar, Camille Deroissart, Marie-Anne Le Solliec, Julie Rondeaux, Séverine Nobis, Charlène Guérin, Fatima Léon, Jean-Claude do Rego, Nicolas Pons, Emmanuelle Le Chatelier, S. Dusko Ehrlich, Gregory Lambert, Pierre Déchelotte, Sergueï O. Fetissov