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Published on: September 8, 2021
Human β-defensin 3 (DEFB103) and its influence on Staphylococcus aureus nasal carriage
Peder Fode1, Marc Stegger, Paal Skytt Andersen
1Laboratory of Microbial Pathogenesis and Host Susceptibility, Department of Microbiological Surveillance and Research, Statens Serum Institut, 5 Artillerivej DK-2300 Copenhagen S, Denmark.
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.
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