Intestinal flora in very low-birth weight infants

Acta Paediatr. 2009 Nov;98(11):1762-7. doi: 10.1111/j.1651-2227.2009.01471.x. Epub 2009 Aug 8.


Aim: To study the early faecal microbiota in very low-birth weight infants (VLBW, <1500 g), possible associations between faecal microbiota and faecal calprotectin (f-calprotectin) and to describe the faecal microbiota in cases with necrotizing enterocolitis (NEC) before diagnosis.

Methods: Stool samples from the first weeks of life were analysed in 48 VLBW infants. Bacterial cultures were performed and f-calprotectin concentrations were measured. In three NEC cases, cultures were performed on stool samples obtained before diagnosis.

Results: Bifidobacteria and lactobacilli were often identified in the first stool sample, 55% and 71% of cases, respectively within the first week of life. A positive correlation between lactic acid bacteria (LAB) and volume of enteral feed was found. Other bacteria often identified were Escherichia coli, Enterococcus and Staphyloccus sp. F-calprotectin was not associated with any bacterial species. All NEC cases had an early colonization of LAB. Prior to onset of disease, all cases had a high colonization of non-E. coli Gram-negative species.

Conclusion: In contrast to the previous studies in VLBW infants, we found an early colonization with LAB. We speculate that this may be due to early feeding of non-pasteurized breast milk.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Distribution
  • Candida / isolation & purification
  • Catalase / biosynthesis
  • Colony Count, Microbial
  • Enterocolitis, Necrotizing / diagnosis
  • Enterocolitis, Necrotizing / microbiology*
  • Feces / chemistry
  • Feces / microbiology*
  • Female
  • Gram-Negative Bacteria / isolation & purification
  • Gram-Negative Bacteria / metabolism
  • Gram-Positive Bacteria / isolation & purification
  • Gram-Positive Bacteria / metabolism
  • Humans
  • Infant, Newborn
  • Infant, Premature
  • Infant, Premature, Diseases / diagnosis
  • Infant, Premature, Diseases / microbiology*
  • Infant, Very Low Birth Weight*
  • Intestines / microbiology*
  • Lactobacillus / isolation & purification
  • Lactose / biosynthesis
  • Leukocyte L1 Antigen Complex / analysis
  • Linear Models
  • Male


  • Leukocyte L1 Antigen Complex
  • Catalase
  • Lactose