RESUMO
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. DESIGN: 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.