Abnormal intestinal motor patterns explain enteric colonization with gram-negative bacilli in late radiation...

Area of Science:

• Gastroenterology
• Radiation Oncology
• Microbiology

Background:

• Abdominal radiotherapy can lead to bacterial overgrowth and intestinal pseudo-obstruction.
• Absence of the intestinal migrating motor complex (MMC) is linked to bacterial overgrowth.

Purpose of the Study:

• To investigate the relationship between intestinal motility patterns and gastrointestinal microflora.
• To clarify the pathogenesis of late radiation enteropathy.

Main Methods:

• Prolonged ambulatory manometry in 41 female patients with late radiation enteropathy.
• Gastric and duodenal sample cultures for gram-negative bacilli (GNB).
• Glucose gas test, [14C]D-xylose breath test, gastric pH, and short-chain fatty acid analysis.

Main Results:

• MMC intensity significantly correlated with GNB levels in the stomach (61%) and duodenum (71%).
• Abnormal MMC index and irregular motility bursts were strong predictors of GNB (86%).
• Fasting gastric pH predicted overall gastric bacterial counts but not GNB presence.

Conclusions:

• Impaired intestinal motility is a causal factor for gastrointestinal colonization with GNB.
• Hypochlorhydria contributes to non-specific gastric bacterial colonization.
• Abnormal motility and GNB in the proximal small intestine are crucial in severe late radiation enteropathy pathogenesis.