title: Acidification of formula reduces bacterial translocation and gut colonization in a neonatal rabbit model.
abstract: OBJECTIVE
  The authors hypothesized that gastric acidity is protective because it is bactericidal. They tested acidified formula for protection against gut colonization and bacterial translocation.
  
  
  METHODS
  In vitro: Formula was acidified to pH of 2, 3, 4, 5 and innoculated with Enterobacter. Growth over time was quantitatively assessed. In vivo: 442 premature rabbit pups were sorted randomly and fed formula of pH 2, 3, 4, or 7, with ranitidine. Two models were utilized: (1) with bacterial challenge using a known acid sensitive organism, (2) without bacterial challenge to simulate natural gut colonization and to test against organisms of unknown acid sensitivity. Normal acid animals received pH 7 formula, no ranitidine. On day 3, the mesenteric lymph nodes (MLN), spleen, liver, and cecum were harvested and cultured.
  
  
  RESULTS
  Bacterial growth was inhibited at pH 2 and 3, growth was logarithmic above pH 4 (P<.001). Total and organ-specific translocation was reduced at pH 3 and below in both models (P<.05). Translocation with formula pH 3 equaled normal acid animals. Quantitative cecal colonization was reduced in pups receiving pH 3 and below in both models (P<.05).
  
  
  CONCLUSIONS
  Acidification of formula below pH 4 is bactericidal to enteric organisms. Acidified formula decreases bacterial translocation and gut colonization.
authors.affiliation: Department of Pediatric Surgery, Arkansas Children's Hospital, University of Arkansas for Medical Sciences, Little Rock, AK, USA.
authors.forename: J R
authors.initials: JR
authors.lastname: Mehall
authors.forename: R
authors.initials: R
authors.lastname: Northrop
authors.forename: D A
authors.initials: DA
authors.lastname: Saltzman
authors.forename: R J
authors.initials: RJ
authors.lastname: Jackson
authors.forename: S D
authors.initials: SD
authors.lastname: Smith
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D018988:Bacterial Translocation / Q000502:physiology*; D002432:Cecum / Q000382:microbiology; D016972:Enterobacter cloacae / Q000502:physiology; D005744:Gastric Acid / Q000378:metabolism*; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D006851:Hydrochloric Acid / Q000008:administration & dosage; D006863:Hydrogen-Ion Concentration; D007225:Infant Food; D008099:Liver / Q000382:microbiology; D008198:Lymph Nodes / Q000382:microbiology; D011817:Rabbits; D011899:Ranitidine / Q000494:pharmacology; D013154:Spleen / Q000382:microbiology
chemical_list: D006635:Histamine H2 Antagonists; D011899:Ranitidine; D006851:Hydrochloric Acid