title: Bacterial succession in the colon during childhood and adolescence: molecular studies in a southern Indian village.
abstract: BACKGROUND
  The colonic bacterial flora, largely anaerobic, is believed to establish and stabilize in the first 2 y of life.
  
  
  OBJECTIVE
  This study was undertaken to determine whether the bacterial flora of the colon undergoes further changes (succession) during childhood and adolescence.
  
  
  METHODS
  This cross-sectional study examined fecal samples from 130 healthy children and adolescents in the age group 2-17 y and from 30 healthy adults (median age: 42 y) residing in a single village in southern India. DNA was extracted and subjected to 16S rDNA-targeted real-time polymerase chain reaction to determine the relative predominance of Bifidobacterium genus, Bacteroides-Prevotella-Porphyromonas group, Lactobacillus acidophilus group, Eubacterium rectale, and Faecalibacterium prausnitzii.
  
  
  RESULTS
  Bifidobacterium species and Bacteroides-Prevotella group were dominant fecal bacteria overall. E. rectale and Lactobacillus species were considerably less abundant. Clear age-related differences emerged, with a steep decline in Bifidobacterium species in adults (P < 0.0001), a steep decline of Lactobacillus species >5 y of age (P < 0.0001), an increase in Bacteroides during late adolescence and in adults (P = 0.0040), an increase in E. rectale during childhood and adolescence followed by a steep decline in adults (P < 0.0001), and a late childhood peak of F. prausnitzii with decline in adolescents and adults (P < 0.0001).
  
  
  CONCLUSIONS
  Changes in the bacterial flora occur during childhood and adolescence characterized by reduction in Lactobacillus and Bifidobacterium species and an increase in Bacteroides, E rectale, and F. prausnitzii peaked during late childhood in this population.
authors.affiliation: Wellcome Trust Research Laboratory, Department of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India.
authors.forename: Ramadass
authors.initials: R
authors.lastname: Balamurugan
authors.forename: Harish P
authors.initials: HP
authors.lastname: Janardhan
authors.forename: Sarah
authors.initials: S
authors.lastname: George
authors.forename: Sucharita Priya
authors.initials: SP
authors.lastname: Chittaranjan
authors.forename: Balakrishnan S
authors.initials: BS
authors.lastname: Ramakrishna
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000375:Aging; D001419:Bacteria / Q000145:classification* / Q000302:isolation & purification*; D001439:Bacteroides / Q000145:classification / Q000302:isolation & purification; D001644:Bifidobacterium / Q000145:classification / Q000302:isolation & purification; D002648:Child; D002675:Child, Preschool; D003106:Colon / Q000382:microbiology*; D015169:Colony Count, Microbial; D003430:Cross-Sectional Studies; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005051:Eubacterium / Q000145:classification / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology*; D005260:Female; D006801:Humans; D007194:India; D007779:Lactobacillus acidophilus / Q000145:classification / Q000302:isolation & purification; D008297:Male; D008875:Middle Aged; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods; D013045:Species Specificity; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal