Translational Investigation | Published:

Translational Investigation

The role of breast milk in the colonization of neonatal gut and skin with coagulase-negative staphylococci

Pediatric Research volume 82, pages 759767 (2017) | Download Citation



We aimed to determine the genetic relatedness between Staphylococcus epidermidis colonizing breast milk (BM) and BM-fed neonates during the first month of life.


S. epidermidis was isolated from the stool and skin swabs of 20 healthy term and 49 preterm neonates hospitalized in the neonatal intensive care unit and from the BM of mothers once a week and typed by multilocus variable-number tandem-repeat analysis. Virulence-related genes were determined by PCR.


The gut (95%) and skin (100%) of term neonates were colonized with strains genetically similar to those in BM and carrying mecA and IS256 at low rate (both <6.7%). In preterm neonates, colonization with strains genetically similar to those in BM was low on the skin (34.7%) and in the gut in the first week of life (14.3%), but the prevalence of mecA (>90.6%) and IS256 (>61.7%) was high. By the fourth week, in the gut of preterm neonates the prevalence of mecA (73.8%) and IS256 (18.4%) decreased, but colonization with strains genetically similar to those in BM increased (83.7%).


During early life, the skin and gut of preterm neonates is colonized with S. epidermidis that is distinct from strains found in BM, but gradually the gut is enriched with strains genetically similar to those in BM, as in term neonates.

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We thank the study nurses Eve Kaur, Marika Zuihhina, and Tuuli Tammekunn, laboratory assistants Dagmar Hoidmets, Tiiu Rööp, and Sandra Sokmann, undergraduate student Magda Karakai, and all study participants.

Author information


  1. Department of Microbiology, Institute of Biomedicine and Translational Medicine, University of Tartu, Tartu, Estonia

    • Hiie Soeorg
    • , Sirli Treumuth
    • , Kristi Huik
    •  & Irja Lutsar
  2. Paediatric Intensive Care Unit, Clinic of Anaesthesiology and Intensive Care, Tartu University Hospital, Tartu, Estonia

    • Tuuli Metsvaht
    •  & Imbi Eelmäe
  3. Neonatal Unit, Children's Clinic, Tartu University Hospital, Tartu, Estonia

    • Mirjam Merila
  4. Microbiology Department, Laboratory, Diagnostics Division, North Estonia Medical Centre, Tallinn, Estonia

    • Marika Jürna-Ellam
  5. Department of Anaesthesiology and Intensive Care, Tallinn Children’s Hospital, Tallinn, Estonia

    • Mari-Liis Ilmoja


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The authors declare no conflict of interest.

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Correspondence to Hiie Soeorg.

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Statement of financial support

This study was supported by Estonian Research Council (IUT34-24), European Regional Development Fund (Project SFOS WP1-NeuroAIDS), Archimedes Foundation (Project No. 3.2.1001.11-0032) and the European Society for Paediatric Infectious Diseases (ESPID Small Grant Award).