Antibiotic use was associated with the reduction of Bacteroides and Bifidobacterium and the outgrowth of Campylobacter, Streptococcus, Leuconostoc or yeasts such as Candida albicans in the intestinal microbial communities.14,107-109 As we are born sterile, bacterial colonization during and shortly after birth also plays an important role in shaping the communities of gut microbiota.