A composition comprising a probiotic strain of Lactobacillus wherein said probiotic Lactobacillus is the species Lactobacillus murinus； the strain selected from the group consisting of Lactobacillus murinus NCIMB 41194 (AHC 1222)； Lactobacillus murinus NCIMB 41195 (AHC 3133), Lactobacillus murinus NCIMB 41196 (AHC 5323)； Lactobacillus murinus NCIMB 41197 (AHC 6331), obtained by isolation from a dissected and washed mammalian gastrointestinal tract for use in a method for the treatment of a companion animal selected from the regulation of the immune system of a companion animal, said said comprising regulation treat or prevent autoimmune disease in a companion animal； treat or prevent inflammation in a companion animal or mixtures thereof, maintain or improve the health of the skin and / or the coating system of a companion animal, comprising treating or preventing atopic skin disease in animals of company； prevent weight loss during and after an infection in a companion animal, treat or prevent urinary tract conditions in companion animals, prevent or treat infection of the gastrointestinal tract of a companion animal, or mixtures thereof； wherein said companion animal is selected from the group consisting of canines and felines.Una composición que comprende una cepa probiótica de Lactobacillus en donde dicho Lactobacillus probiótico es la especie Lactobacillus murinus； la cepa seleccionada del grupo que consiste en Lactobacillus murinus NCIMB 41194 (AHC 1222)； Lactobacillus murinus NCIMB 41195 (AHC 3133), Lactobacillus murinus NCIMB 41196 (AHC 5323)； Lactobacillus murinus NCIMB 41197 (AHC 6331), obtenida mediante aislamiento a partir de tracto gastrointestinal de mamífero diseccionado y lavado para usar en un método para el tratamiento de un animal de compañía seleccionado de entre regulación del sistema inmunológico de un animal de compañía, comprendiendo dicha regulación tratar o prevenir la enfermedad autoinmune en un animal de compañía； tratar o prevenir la inf
