ABSTRACT
Staphylococcus aureus expresses a panel of cell wall-anchored adhesins, including proteins belonging to the microbial surface components recognizing adhesive matrix molecule (MSCRAMM) family, exemplified by the serine-aspartate repeat protein D (SdrD), which serve key roles in colonization and infection. Deletion of sdrD from S. aureus subsp. aureus strain NCTC8325-4 attenuated bacterial survival in human whole blood ex vivo, which was associated with increased killing by human neutrophils. Remarkably, SdrD was able to inhibit innate immune-mediated bacterial killing independently of other S. aureus proteins, since addition of recombinant SdrD protein and heterologous expression of SdrD in Lactococcus lactis promoted bacterial survival in human blood. SdrD contributes to bacterial virulence in vivo, since fewer S. aureus subsp. aureus NCTC8325-4 ΔsdrD bacteria than bacteria of the parent strain were recovered from blood and several organs using a murine intravenous infection model. Collectively, our findings reveal a new property of SdrD as an important key contributor to S. aureus survival and the ability to escape the innate immune system in blood.
FOOTNOTES
- Received 1 July 2016.
- Returned for modification 25 July 2016.
- Accepted 8 October 2016.
- Accepted manuscript posted online 17 October 2016.
Supplemental material for this article may be found at https://doi.org/10.1128/IAI.00559-16 .
- Copyright © 2016 Askarian et al.
This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license .
