Bacterial overgrowth is a particular concern for many children with digestive disorders. Normally, the entire gut contains healthy bacteria, commonly called gut flora. When the amount of bacteria increases exponentially, or “bad” bacteria thrives instead of healthy bacteria, children may develop bacterial overgrowth. Bacterial overgrowth can be found throughout the gut, but is most common in the small intestine or small bowel. As a result, it is sometimes referred to as Small Intestinal Bacterial Overgrowth (SIBO), or Small Bowel Bacterial Overgrowth (SBBO).

Bacterial overgrowth typically leads to gas, bloating, diarrhea, vomiting, and abdominal discomfort. Severe cases may contribute to malnutrition due to malabsorption, along with conditions like anemia and vitamin deficiencies.

Causes of Bacterial Overgrowth

Bacterial overgrowth may be caused by a number of factors. Some of the most common causes are listed below:

  • Motility or structural problems that cause slow motility, delayed emptying, constipation, or otherwise slow the passage of food through the gut, causing extra bacteria to grow.
  • Frequent antibiotic use.
  • Malabsorption or other conditions that leave undigested food in the digestive tract.
  • Poor diet.
  • Children without a gall bladder or who do not produce bile appropriately to break down food.
  • Children with cystic fibrosis or other conditions that affect absorption.
  • Children with an impaired immune system.
  • Surgery to the bowel, including removal of the ileocecal valve, which then allows stool to reflux into the small intestine.

Diagnosis and Treatment

Diagnosis is typically made once other causes are excluded. Breath tests may also help to determine if certain byproducts from digestion occur in large quantities, suggesting excess bacterial growth. Finally, a gastroenterologist may perform an upper endoscopy to examine tissue and the contents of the small intestine.

Treating bacterial overgrowth can be challenging, because it is difficult to rid the body of the bad bacteria without getting rid of all the helpful bacteria. The following treatments are typical:

  • Probiotics
  • Antibiotics, especially amoxillin-clavulanate, rifamaxin, or metronidazole
  • Correction of underlying issues, such as motility disorders, structural problems, absorption problems, or immune deficiencies
  • Dietary changes