Abstract: The present invention relates to a novel method for an accurate quantification in intestinal samples of Faecalibacterium prausnitzii phylogroup I members (PHGI) and/or Faecalibacterium prausnitzii phylogroup II members (PHGII). It further relates to a method for detecting intestinal diseases, including the screening, diagnosis, differential diagnosis, and/or monitoring of disease activity or progression in a human subject comprising determining the abundance of PHGI and/or PHGII in an intestinal sample from said subject. Moreover, it relates to a method for the prediction of the efficacy of a drug in the therapeutic treatment of an intestinal disease in a human subject comprising determining the abundance of PHGI and/or PHGII in an intestinal sample from said subject.

Abstract: The present invention concerns methods, in particular in vitro methods, for diagnosing liver fibrosis in a subject suffering from obesity, or for selecting a subject suffering from obesity for liver biopsy or for treatment. The present invention also pertains to methods for screening a probiotic, a prebiotic, a chemical compound or a biological compound suitable for preventing and/or treating liver fibrosis.