Genomic and Surface Proteomic Analysis of the Canine Pathogen Staphylococcus pseudintermedius Reveals Proteins That Mediate Adherence to the Extracellular Matrix

Abstract

Cell wall-associated (CWA) proteins made by Gram-positive pathogens play a fundamental role in pathogenesis. Staphylococcus pseudintermedius is a major animal pathogen responsible for the canine skin disease bacterial pyoderma. Here, we describe the bioinformatic analysis of the family of 18 predicted CWA proteins encoded in the genome of S. pseudintermedius strain ED99 and determine their distribution among a phylogenetically diverse panel of S. pseudintermedius clinical isolates and closely related species of the Staphylococcus intermedius group. In parallel, we employed a proteomic approach to identify proteins presented on the surface of strain ED99 in vitro, revealing a total of 60 surface-localized proteins in one or more phases of growth, including 6 of the 18 genome-predicted CWA proteins. Based on these analyses, we selected two CWA proteins (SpsD and SpsL) encoded by all strains examined and investigated their capacity to mediate adherence to extracellular matrix proteins. We discovered that SpsD and SpsL mediated binding of a heterologous host, Lactococcus lactis, to fibrinogen and fibronectin and that SpsD mediated binding to cytokeratin 10, a major constituent of mammalian skin. Of note, the interaction with fibrinogen was host-species dependent, suggestive of a role for SpsD and SpsL in the host tropism of S. pseudintermedius. Finally, we identified IgG specific for SpsD and SpsL in sera from dogs with bacterial pyoderma, implying that both proteins are expressed during infection. The combined genomic and proteomic approach employed in the current study has revealed novel host-pathogen interactions which represent candidate therapeutic targets for the control of bacterial pyoderma.

Fibronectin Binding Proteins SpsD and SpsL Both Support Invasion of Canine Epithelial Cells by Staphylococcus pseudintermedius

“…1) (15). The primary translation product of SpsD from strain ED99 has an N-terminal secretory signal sequence and a C-terminal cell wall-anchoring domain (the sorting signal) comprising an LPXTG motif, a hydrophobic transmembrane domain, and a short sequence rich in positively charged residues.…”

“…Sporadic cases of human infection have also been reported, including some in individuals exposed to colonized household pets (4)(5)(6)(7). Genome sequence analysis (8,9) indicates that S. pseudintermedius could encode many potential virulence factors, including toxins, enzymes, and surface proteins, some of which can promote adhesion of the bacterium to the surface of epithelial cells (10)(11)(12)(13) and to components of the extracellular matrix (14,15).…”

Design and application of a loop-mediated isothermal amplification assay for the rapid detection of Staphylococcus pseudintermedius

“…A yield of approximately 394 ng per µl of DNA was observed with the spsL assay, compared to 11.1 µg per 25 µl previously reported for a prostate-specific antigen LAMP reaction. 15 Because the spsL gene has only recently (2011) been identified, 1 the prevalence of this gene among S. pseudintermedius is unknown. It was therefore imperative to evaluate the assay against a wide range of S. pseudintermedius strains originating from different dog breeds, and from geographically dissimilar regions.…”

Characterization of recombinant wild-type and nontoxigenic protein A from Staphylococcus pseudintermedius

“…[28] found that S. pseudintermedius possess two genes orthologous to S. aureus spa, spsP (encoding SpsP) and spsQ (encoding SpsQ, analogous to SpA). Balachandran et al .…”