title: Fecal microbiota in patients receiving enteral feeding are highly variable and may be altered in those who develop diarrhea.
abstract: BACKGROUND
  The pathogenesis of diarrhea in patients receiving enteral feeding includes colonic water secretion, antibiotic prescription, and enteropathogenic colonization, each of which involves an interaction with the gastrointestinal microbiota.
  
  
  OBJECTIVE
  The objective was to investigate temporal changes in the concentrations of fecal microbiota and short-chain fatty acids (SCFAs) in patients starting 14-d of enteral feeding and to compare these changes between patients who do and do not develop diarrhea.
  
  
  METHODS
  Twenty patients starting exclusive nasogastric enteral feeding were monitored for 14 d. Fecal samples were collected at the start, middle, and end of this period and were analyzed for major bacterial groups by using culture independent fluorescence in situ hybridization and for SCFAs by using gas-liquid chromatography.
  
  
  RESULTS
  Although no significant changes in fecal microbiota or SCFAs were observed during enteral feeding, stark alterations occurred within individual patients. Ten patients (50%) developed diarrhea, and these patients had significantly higher concentrations of clostridia (P = 0.026) and lower concentrations (P = 0.069) and proportions (P = 0.029) of bifidobacteria. Patients with and without diarrhea had differences in the proportion of bifidobacteria (median: 0.4% and 3.7%; interquartile range: 0.8 compared with 4.3; P = 0.035) and clostridia (median: 10.4% and 3.7%; interquartile range: 14.7 compared with 7.0; P = 0.063), respectively, even at the start of enteral feeding. Patients who developed diarrhea had higher concentrations of total fecal SCFAs (P = 0.044), acetate (P = 0.029), and butyrate (P = 0.055).
  
  
  CONCLUSIONS
  Intestinal dysbiosis occurs in patients who develop diarrhea during enteral feeding and may be involved in its pathogenesis.
authors.affiliation: Nutritional Sciences Division, Diet and Gastrointestinal Health, King's College London, London, UK. kevin.whelan@kcl.ac.uk
authors.forename: Kevin
authors.initials: K
authors.lastname: Whelan
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Judd
authors.forename: Kieran M
authors.initials: KM
authors.lastname: Tuohy
authors.forename: Glenn R
authors.initials: GR
authors.lastname: Gibson
authors.forename: Victor R
authors.initials: VR
authors.lastname: Preedy
authors.forename: Moira A
authors.initials: MA
authors.lastname: Taylor
mesh_terms: D000368:Aged; D001644:Bifidobacterium / Q000254:growth & development* / Q000302:isolation & purification; D002849:Chromatography, Gas / Q000379:methods; D003013:Clostridium / Q000254:growth & development* / Q000302:isolation & purification; D015169:Colony Count, Microbial; D003967:Diarrhea / Q000382:microbiology*; D004750:Enteral Nutrition / Q000009:adverse effects; D005232:Fatty Acids, Volatile / Q000032:analysis / Q000096:biosynthesis*; D005243:Feces / Q000382:microbiology*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008297:Male; D019936:Probiotics; D011446:Prospective Studies
chemical_list: D005232:Fatty Acids, Volatile