The present invention relates to bacterial compositions and methods of use thereof. The bacterial compositions may include two or more bacteria of the genera Faecalibacterium, Lachnospira, Veillonella or Rothia. The bacterial compositions may be used in treating gut dysbiosis, asthma, allergy, or atopy, or altering the gut microbiota, or populating the gastrointestinal tract, in a subject in need thereof.