Human β-defensin 3 (DEFB103) and Its Influence on Staphylococcus Aureus Nasal Carriage

Int J Infect Dis. 2011 Jun;15(6):e388-94. doi: 10.1016/j.ijid.2011.02.003. Epub 2011 Mar 9.


Objective: The DEFB103 gene encodes human β-defensin 3, which has a high activity against Staphylococcus aureus. In the general population 20% are persistent nasal carriers of S. aureus, which is a problem for their general health. DEFB103 shows extensive variation in copy number. Copy number variations (CNVs) are believed to play a role in susceptibility to certain diseases. The possible associations between CNVs, mRNA, and nasal S. aureus carriage status were investigated.

Methods: We used the pyrosequencing-based paralog ratio test to determine the DEFB103 copy number. Nasal swabs were collected for RNA and S. aureus determination. S. aureus genotypes were determined by spa typing, and real-time PCR was used to determine DEFB103 mRNA expression.

Results: The DEFB103 CNV varied from 2 to 8 copies per diploid genome. No significant difference in copy number was observed among the groups. We found 74% of the volunteers to be non-carriers, 20% to be persistent carriers, and 6% to be intermittent carriers. The S. aureus isolates linked to more than 16 clonal lineages. mRNA expression varied extensively, but no significant differences were observed between the groups. We did not find a linear correlation between CNV and mRNA expression.

Conclusions: The results indicate that DEFB103 CNV does not influence S. aureus carrier status.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carrier State / microbiology*
  • Female
  • Gene Dosage*
  • Genetic Variation
  • Humans
  • Male
  • Middle Aged
  • Nasal Cavity / microbiology*
  • Polymerase Chain Reaction
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Sequence Analysis, DNA
  • Staphylococcal Infections / microbiology*
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / growth & development
  • Staphylococcus aureus / physiology*
  • beta-Defensins / genetics*
  • beta-Defensins / physiology*


  • DEFB103A protein, human
  • RNA, Messenger
  • beta-Defensins