title: Conditions of bifidobacterial colonization in preterm infants: a prospective analysis.
abstract: BACKGROUND
  Premature birth results in a delayed and abnormal qualitative pattern of gut colonization. This abnormal pattern is thought to affect intestinal development and contribute to a higher risk of gastrointestinal infectious diseases such as neonatal necrotizing enterocolitis (NEC). In particular, bifidobacteria are thought to play a major role. We therefore studied bifidobacterial colonization in preterm infants during the first month of life.
  
  
  METHODS
  Fecal samples were prospectively analyzed in 52 infants born at a gestational age ranging from 30 to 35 weeks fed with a preterm formula alone and, in 18, with their mother's milk. Fecal samples were collected twice per week during the hospital stay. Bifidobacterial colonization was analyzed with culture and a molecular method.
  
  
  RESULTS
  Bifidobacterial colonization occurred in 18 infants at a median age of 11 days, always greater than the corrected mean gestational age of 35.4 weeks (SD, 0.9) and greater than 34 weeks for 16 of 18. Colonization by bifidobacteria was affected by neither birthweight nor mode of delivery nor antibiotics given to the mother or infant. In contrast, birth gestational age had a significant impact on colonization by bifidobacteria (P < 0.05), which always occurred in children born at a birth gestational age greater than 32.9 weeks (P < 0.05).
  
  
  CONCLUSIONS
  Birth gestational age seems to act as a major determinant of bifidobacterial colonization in the premature infant, suggesting the role of gut maturation, a finding that should probably be taken into account in manipulations of the gut flora aimed at reducing NEC.
authors: Department of Microbiology, EA 4065, Faculty of Pharmaceutical and Biological Sciences, Université Paris Descartes, Paris, France. marie-jose.butel@univ-paris5.fr
authors: Marie-José
authors: MJ
authors: Butel
authors: Antonia
authors: A
authors: Suau
authors: Florence
authors: F
authors: Campeotto
authors: Fabien
authors: F
authors: Magne
authors: Julio
authors: J
authors: Aires
authors: Laurent
authors: L
authors: Ferraris
authors: Nicolas
authors: N
authors: Kalach
authors: Bernard
authors: B
authors: Leroux
authors: Christophe
authors: C
authors: Dupont
mesh_terms: D039941:Bifidobacteriales Infections / Q000382:microbiology*; D002657:Child Development / Q000502:physiology; D005243:Feces / Q000382:microbiology; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007422:Intestines / Q000382:microbiology* / Q000502:physiology; D047928:Premature Birth / Q000382:microbiology*; D011446:Prospective Studies