title: Antimicrobial protein and Peptide concentrations and activity in human breast milk consumed by preterm infants at risk of late-onset neonatal sepsis.
abstract: OBJECTIVE
  We investigated the levels and antimicrobial activity of antimicrobial proteins and peptides (AMPs) in breast milk consumed by preterm infants, and whether deficiencies of these factors were associated with late-onset neonatal sepsis (LOS), a bacterial infection that frequently occurs in preterm infants in the neonatal period.
  
  
  METHODS
  Breast milk from mothers of preterm infants (≤ 32 weeks gestation) was collected on days 7 (n = 88) and 21 (n = 77) postpartum. Concentrations of lactoferrin, LL-37, beta-defensins 1 and 2, and alpha-defensin 5 were measured by enzyme-linked immunosorbent assay. The antimicrobial activity of breast milk samples against Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Streptococcus agalactiae was compared to the activity of infant formula, alone or supplemented with physiological levels of AMPs. Samples of breast milk fed to infants with and without subsequent LOS were compared for levels of AMPs and inhibition of bacterial growth.
  
  
  RESULTS
  Levels of most AMPs and antibacterial activity in preterm breast milk were higher at day 7 than at day 21. Lactoferrin was the only AMP that limited pathogen growth >50% when added to formula at a concentration equivalent to that present in breast milk. Levels of AMPs were similar in the breast milk fed to infants with and without LOS, however, infants who developed LOS consumed significantly less breast milk and lower doses of milk AMPs than those who were free from LOS.
  
  
  CONCLUSIONS
  The concentrations of lactoferrin and defensins in preterm breast milk have antimicrobial activity against common neonatal pathogens.
authors: Centre for Neonatal Research and Education, University of Western Australia, Perth, Western Australia, Australia; School of Paediatrics and Child Health, University of Western Australia, Perth, Western Australia, Australia.
authors: Stephanie
authors: S
authors: Trend
authors: Centre for Neonatal Research and Education, University of Western Australia, Perth, Western Australia, Australia; School of Paediatrics and Child Health, University of Western Australia, Perth, Western Australia, Australia; Neonatal Clinical Care Unit, King Edward Memorial Hospital for Women, Perth, Western Australia, Australia.
authors: Tobias
authors: T
authors: Strunk
authors: School of Paediatrics and Child Health, University of Western Australia, Perth, Western Australia, Australia.
authors: Julie
authors: J
authors: Hibbert
authors: Centre for Neonatal Research and Education, University of Western Australia, Perth, Western Australia, Australia; Neonatal Clinical Care Unit, King Edward Memorial Hospital for Women, Perth, Western Australia, Australia.
authors: Chooi Heen
authors: CH
authors: Kok
authors: School of Public Health, Curtin University, Perth, Australia.
authors: Guicheng
authors: G
authors: Zhang
authors: School of Women's and Infants' Health, University of Western Australia, Perth, Australia.
authors: Dorota A
authors: DA
authors: Doherty
authors: School of Paediatrics and Child Health, University of Western Australia, Perth, Western Australia, Australia.
authors: Peter
authors: P
authors: Richmond
authors: Murdoch Childrens Research Institute, Parkville, Victoria, Australia; University of Melbourne, Melbourne, Victoria, Australia.
authors: David
authors: D
authors: Burgner
authors: Centre for Neonatal Research and Education, University of Western Australia, Perth, Western Australia, Australia; School of Paediatrics and Child Health, University of Western Australia, Perth, Western Australia, Australia; Neonatal Clinical Care Unit, King Edward Memorial Hospital for Women, Perth, Western Australia, Australia.
authors: Karen
authors: K
authors: Simmer
authors: The University of Edinburgh/MRC Centre for Inflammation Research, Queen's Medical Research Institute, Edinburgh, United Kingdom.
authors: Donald J
authors: DJ
authors: Davidson
authors: Centre for Neonatal Research and Education, University of Western Australia, Perth, Western Australia, Australia; School of Paediatrics and Child Health, University of Western Australia, Perth, Western Australia, Australia; School of Veterinary and Life Sciences, Murdoch University, Perth, Western Australia, Australia.
authors: Andrew J
authors: AJ
authors: Currie
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000032:analysis / Q000494:pharmacology*; D016022:Case-Control Studies; D004326:Drinking; D004347:Drug Interactions; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D007501:Iron / Q000494:pharmacology; D008297:Male; D008895:Milk, Human / Q000737:chemistry*; D011247:Pregnancy; D012306:Risk; D018805:Sepsis / Q000382:microbiology*
chemical_list: D023181:Antimicrobial Cationic Peptides; D007501:Iron
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