title: Probiotics and antimicrobial protein and peptide levels in preterm infants.
abstract: OBJECTIVE
  To characterise the secreted and inducible antimicrobial protein and peptide (APP) levels in a prospective cohort of preterm infants (<30 weeks gestational age) with or without Bifidobacterium breve M16V supplementation during the first month of life.
  
  
  METHODS
  We analysed serial biosamples of infants who did (n = 13) or did not receive (n = 62) B. breve (3 × 109cfu/day). Peripheral blood was obtained on days 1, 14 and 28, and infant stool prior to commencement of probiotic supplementation and on day 21. Levels of APP (bactericidal/permeability inducing protein (BPI), beta defensins 1 and 2, lactoferrin, human cathelicidin, secretory phospholipase A2) in plasma and stool were determined. Further, we characterised induced APP levels in whole blood cultured with live S. epidermidis or with agonists of Toll-like receptors 2/6 and 4.
  
  
  RESULTS
  Stool, plasma and stimulated blood APP levels changed significantly during the first month of life. Supplementation with B. breve did not affect basal or stimulated APP levels except for a transient increase in inducible BPI.
  
  
  CONCLUSIONS
  Supplementation with B. breve does not appear to act via modulation of systemic or enteric APP expression in preterm infants although small effects cannot be excluded. Further work with other probiotic preparations is warranted.
authors.affiliation: Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia.|Neonatal Clinical Care Unit, King Edward Memorial Hospital, Perth, WA, Australia.
authors.forename: Tobias
authors.initials: T
authors.lastname: Strunk
authors.affiliation: Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia.
authors.forename: Julie
authors.initials: J
authors.lastname: Hibbert
authors.affiliation: School of Women's and Infant's Health, University of Western Australia, Perth, WA, Australia.
authors.forename: Dorota
authors.initials: D
authors.lastname: Doherty
authors.affiliation: Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia.
authors.forename: Caitlyn
authors.initials: C
authors.lastname: Granland
authors.affiliation: Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Trend
authors.affiliation: Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia.|Neonatal Clinical Care Unit, King Edward Memorial Hospital, Perth, WA, Australia.
authors.forename: Karen
authors.initials: K
authors.lastname: Simmer
authors.affiliation: Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, VIC, Australia.|Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Burgner
authors.affiliation: Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia.|Neonatal Clinical Care Unit, King Edward Memorial Hospital, Perth, WA, Australia.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Patole
authors.affiliation: Centre for Neonatal Research and Education, School of Paediatrics and Child Health, University of Western Australia, Perth, WA, Australia.|School of Veterinary and Life Sciences, Murdoch University, Perth, WA, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Currie
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000097:blood*; D000069984:Bifidobacterium breve; D005243:Feces / Q000737:chemistry; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood*; D007781:Lactoferrin / Q000097:blood; D008297:Male; D054497:Phospholipases A2, Secretory / Q000097:blood; D019936:Probiotics; D011446:Prospective Studies
chemical_list: D023181:Antimicrobial Cationic Peptides; D054497:Phospholipases A2, Secretory; D007781:Lactoferrin
keywords: 
  Bifidobacterium breve
  ; Antimicrobial proteins and peptides; Preterm infant; Probiotics