Gut microbiota in various childhood disorders: Implication and indications

Table 1 The microbiota in the different parts of the gut

       

Site	pH	Predominant microbiota	Bacterial load (CFU/gram content)	Other factors
Mouth	6.5-7	Bacteria (esp Fusobacterium nucleatum), fungi, viruses and protozoa	700 species	Ideal warm environment
Stomach	Strong acidic	Lactobacilli, streptococci, Lactobacillus, Peptostreptococcus, Helicobacter pylori, and yeasts	Low (102)	Gastric acidity, Acid suppressive therapy, H. pylori colonization, the reflux of bile, mucus thickness and gastric peristalsis
Duodenum	4-5	Lactobacilli and Streptococci	More than (102-104)	Age, diet, antibiotic, and proton pump inhibitor use
Jejunum-ileum	6-7.4	Firmicutes and Proteobacteria	More than duodenum (106-108)	Nutrient reach environment faster transit time, bile acids, and antimicrobial peptide exposure
Colon	Left colon 6.1-7.5; Cecum 5.7; Rectum 6.7	Bacteriodetes (especially the genera Bacteroides and Prevotella) and Firmicutes (especially members of the genus Clostridium). Methanogenic archaea and fungi; Cecum: Aerobic bacteria; Rectum: Bacteroides and Prevotella.	1010-1012	High diversity and density, no digestive secretions, nutrient-poor environment, & slow transit time (30 h)

H. pylori: Helicobacter pylori.