Relationships of Intestinal Lactase and the Small Intestinal Microbiome with Symptoms of Lactose Intolerance and Intake in Adults.

BACKGROUND: Approximately two-thirds of adults are genetically predisposed to decreased lactase activity after weaning, putting them at risk of lactose intolerance. However, symptoms are a poor marker of lactose maldigestion. AIMS: We assessed association between self-reported lactose intolerance and intestinal lactase, lactose intake, and the small intestinal microbiome. METHODS: Patients 18-75 years presenting for upper endoscopy were recruited prospectively. Observational study participants completed a lactose intolerance symptom questionnaire and reported lactose intake. Post-bulbar biopsies were obtained to measure lactase activity and assess the small intestinal mucosal microbiome. We compared intestinal lactase between patients with and without lactose intolerance. We assessed associations between lactose intolerance symptoms and lactase and lactose intake. We examined associations of small bowel microbial composition with self-reported lactose intolerance and symptoms. RESULTS: Among 34 patients, 23 (68%) reported lactose intolerance. Those with lactose intolerance had higher total symptom scores, more frequent bowel urgency, and more bowel movements after consuming dairy. The proportion of individuals with abnormal lactase activity did not differ by lactose intolerance status. Median lactase levels were correlated with total lactose intolerance symptom scores (p = 0.038) and frequency of bowel urgency (p = 0.012). Daily lactose intake did not differ between groups. In 19 patients, we observed significant associations of small intestinal microbiome beta diversity with stool consistency after consuming dairy (p = 0.03). CONCLUSIONS: Intestinal lactase is associated with lactose intolerance symptoms and bowel urgency in adults but does not distinguish the clinical phenotype entirely. Studying other contributing factors (microbiota, diet) may further clarify the pathophysiology of lactose intolerance.

Fulminant Clostridium difficile Infection Cured by Fecal Microbiota Transplantation in a Bone Marrow Transplant Recipient With Critical Neutropenia.

Clostridium difficile infection is the most prevalent health care-associated infection. Treatment relies on antimicrobial therapy with mounting evidence supporting fecal microbiota transplant (FMT) in refractory cases. Cohort studies have documented the safety of FMT in immunocompromised patients. However, the safety of FMT in patients with critically low (<500/µL) absolute neutrophil count is unknown. Currently, in severely immunocompromised bone marrow or solid organ transplant recipients, FMT is delayed until normalization of absolute neutrophil count. We present a patient with absolute neutropenia in whom sequential FMTs were safely and successfully administered, resulting in cure of fulminant C. difficile infection.