Colonisation and interaction between S. epidermidis and S. aureus in the nose and throat of healthy adolescents

  • E. G. A. Fredheim
  • T. Flægstad
  • F. Askarian
  • C. Klingenberg
Article

DOI: 10.1007/s10096-014-2197-5

Cite this article as:
Fredheim, E.G.A., Flægstad, T., Askarian, F. et al. Eur J Clin Microbiol Infect Dis (2015) 34: 123. doi:10.1007/s10096-014-2197-5

Abstract

Nasal colonisation with Staphylococcus aureus is a risk factor for developing nosocomial infections. It has been reported that S. epidermidis may produce a serine protease (Esp) inhibiting S. aureus biofilm formation and nasal colonisation. We aimed to analyse the correlation between S. aureus nasal and/or throat carriage and co-colonisation with S. epidermidis strains carrying esp, and the inhibitory effects of S. epidermidis culture supernatants on S. aureus biofilm formation and growth. We obtained 114 S. epidermidis isolates from the nose and 74 S. aureus from the nose and/or throat of healthy adolescents. S. aureus biofilm formation was analysed in a microtitre plate assay and the prevalence of ica, encoding biofilm formation, and esp was analysed with polymerase chain reaction (PCR). Inhibitory effects of S. epidermidis culture supernatants on S. aureus biofilm formation and growth was analysed in vitro. esp prevalence and expression was correlated with inhibitory effects. We detected biofilm formation in 45/74 (61 %) S. aureus strains. The ica operon was more prevalent in isolates colonising the nose (12/15; 80 %) versus isolates colonising the throat only (8/46; 17 %). Almost two-thirds of S. epidermidis culture supernatants displayed high (≥50 %) S. aureus biofilm inhibitory activity, without affecting growth. We found no correlation between the level of inhibitory activity and S. aureus colonisation. esp was ubiquitous in S. epidermidis, but esp expression did not correlate with biofilm inhibitory activity. S. epidermidis culture supernatants inhibit S. aureus biofilm formation, but do not affect bacterial growth. esp expression was not correlated with the inhibitory effects observed.

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • E. G. A. Fredheim
    • 1
    • 2
  • T. Flægstad
    • 1
    • 2
  • F. Askarian
    • 3
  • C. Klingenberg
    • 1
    • 2
  1. 1.Department of PaediatricsUniversity Hospital of North NorwayTromsøNorway
  2. 2.Paediatric Research Group, Department of Clinical MedicineUniversity of TromsøTromsøNorway
  3. 3.Research Group for Host–Microbe Interactions, Department of Medical BiologyUniversity of TromsøTromsøNorway

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