Surface proteins that promote adherence of Staphylococcus aureusto human desquamated nasal epithelial cells

Abstract

BackgroundThe natural habitat of Staphylococcus aureus is the moist squamous epithelium in the anterior nares. About 20% of the human population carry S. aureus permanently in their noses and another 60% of individuals are intermittent carriers. The ability of S. aureus to colonize the nasal epithelium is in part due to expression of surface proteins clumping factor B (ClfB) and the iron-regulated surface determinant A (IsdA), which promote adhesion to desquamated epithelial cells present in the anterior part of the nasal vestibule. S. aureus strain Newman defective in IsdA and ClfB exhibited reduced but not completely defective adherence to squamous cells in indicating that other cell surface components might also contribute.ResultsSurface proteins IsdA, ClfB, and the serine-aspartic acid repeat proteins SdrC, SdrD and SdrE were investigated to determine their contribution to the adherence of S. aureus to desquamated nasal epithelial cells. This was achieved by expression of ClfB, IsdA, SdrC, SdrD and SdrE on the surface of the surrogate Gram-positive host Lactococcus lactis and by isolating mutants of S. aureus Newman defective in one or more factor. The level of adherence of strains to squamous cells isolated from the nares of volunteers was measured. Results consistently showed that ClfB, IsdA, SdrC and SdrD each contributed to the ability of S. aureus to adhere to squamous cells. A mutant lacking all four proteins was completely defective in adherence.ConclusionThe ability of S. aureus Newman to adhere to desquamated nasal epithelial cells is multifactorial and involves SdrD and SdrC as well as ClfB and IsdA.

Fibrinogen Is a Ligand for the Staphylococcus aureus Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMM) Bone Sialoprotein-binding Protein (Bbp)

“…The non-pathogenic bacterium L. lactis has been successfully used as a heterologous host to display full-length forms of MSCRAMMs on its cell surface (23). This system was used to determine whether Bbp expressed on the surface of a bacterium could recognize the binding domain identified for recombinant Bbp N2N3 in Fg A␣.…”

“…Wells were incubated with 0.1 ml of bacterial suspension for 1.5 h at 30°C for L. lactis or 37°C for S. aureus strains. Attached bacteria were detected by crystal violet staining as described previously (23).…”

“…The plasmid was purified and transformed into electrocompetent S. aureus RN4220 and plated on brain heart infusion broth with chloramphenicol. Subsequently, pCU1-Bbp was electroporated into electrocompetent Newman DU6023 clfA5 isdA clfB::Em r ⌬sdrCDE::Tc r cells (23). Bacterial Adherence Assays-L. lactis-pKS80-Bbp, L. lactispKS80, S. aureus Newman DU6023-pCU1-Bbp, and Newman DU6023-pCU1 cells were washed and resuspended to A 600 of 1.0 or 2.0 for L. lactis and S. aureus, respectively, in PBS supplemented with 0.5 mM magnesium chloride and 0.1 mM calcium chloride Microtiter wells were coated with Fg A␣1-560 or Fg A␣1-575, washed, and blocked with PBS, 1% BSA.…”

Antibacterial Effect of Ethanolic Extract of Allium sativum on Biofilm Forming Staphylococcus aureus which Cause Folliculitis

“…Staphylococcus aureus can produce a multilayered biofilm embedded within a glycocalyx or slime layer with heterogeneous protein expression Staphylococcus aureus biofilm mode of growth is tightly regulated by complex genetic factors. Host immune responses against persistent biofilm infections are largely ineffective and lead to chronic disease (Corrigan et al, 2009). …”

Disruption of staphylococcal aggregation protects against lethal lung injury

“…It is understood from studies in cultured cells that alveolar stabilization of S. aureus might involve binding of bacterial surface proteins to host molecules, including cytokine receptors (6) and adhesive matrix molecules that recognize microbial surface components (7). Studies in vitro indicate that the bacteria may stabilize through biofilm formation (8,9), charge interactions (10), or PhnD, the substrate-binding protein of the bacterial ATP-binding cassette (ABC) transporter for phosphonates (11).…”