title: Bacterial invasion of HT29-MTX-E12 monolayers: effects of human breast milk.
abstract: OBJECTIVE
  The supramucosal gel, crucial for gut barrier function, might be compromised in necrotizing enterocolitis (NEC). Breast milk is associated with a reduced incidence of NEC. We compared the effects of human breast milk (BM) versus a neonatal formula, Nutriprem 1 (FF), on adherence, internalisation, and penetration of NEC-associated Escherichia coli through monolayers of mucus producing intestinal cells, HT29-MTX-E12 (E12).
  
  
  METHODS
  E12 cells were grown to confluence on membranes permeable to bacteria. E. coli, reference strain and isolated from a NEC-affected intestine, were cultured in LB broth, labelled with fluorescein and biotinylated. Bacteria were suspended in tissue culture medium (TC) or mixtures of TC with BM or FF and applied to the E12 cultures. Bacterial numbers were assessed by fluorescence. DyLight 650-labelled neutravidin, which cannot cross cell membrane, evaluated extracellular bacteria. Fluorescence of basolateral medium was measured to quantify translocation. Bacterial concentrations were compared using the Mann Whitney U test.
  
  
  RESULTS
  After 1h exposure, E12 cultures adhered or internalised more NEC-derived bacteria than standard strain E. coli and more suspended in FF than BM (P<0.001). A greater proportion of NEC-derived bacteria internalised when suspended in TC or BM. In FF, the NEC-derived strain internalised least. More translocation occurred in BM incubations compared to FF in the first 1-4h: NEC-E. coli less than the reference strain. After 24h translocated bacterial populations were equal.
  
  
  CONCLUSIONS
  In this pilot study, breast milk was associated with relatively less adhesion and internalisation of NEC-associated E. coli to mucus covered E12s compared to formula milk.
authors: University of Bristol, School of Clinical Sciences, Bristol Dental Hospital, Bristol, BS1 2LY, UK.
authors: Tim
authors: T
authors: Hall
authors: David
authors: D
authors: Dymock
authors: Anthony P
authors: AP
authors: Corfield
authors: Gillian
authors: G
authors: Weaver
authors: Mark
authors: M
authors: Woodward
authors: Monica
authors: M
authors: Berry
mesh_terms: D018407:Bacterial Physiological Phenomena; D002478:Cells, Cultured; D020345:Enterocolitis, Necrotizing / Q000382:microbiology; D004926:Escherichia coli / Q000502:physiology*; D019073:HT29 Cells; D006801:Humans; D007422:Intestines / Q000166:cytology*; D008895:Milk, Human; D010865:Pilot Projects