Staphylococcus aureus surface proteins involved in adaptation to oxacillin identified using a novel cell shaving approach.
Staphylococcus aureus is a Gram-positive pathogen responsible for a variety of infections, and some strains are resistant to virtually all classes of antibiotics. Cell shaving proteomics using a novel probability scoring algorithm to compare the surfaceomes of the methicillin-resistant, laboratory-adapted S. aureus COL strain with a COL strain in vitro adapted to high levels of oxacillin (APT). APT displayed altered cell morphology compared with COL and increased aggregation in biofilm assays. Increased resistance to β-lactam antibiotics was observed, but adaptation to oxacillin did not confer multidrug resistance. Analysis of the S. aureus COL and APT surfaceomes identified 150 proteins at a threshold determined by the scoring algorithm. Proteins unique to APT included the LytR-CpsA-Psr (LCP) domain-containing MsrR and SACOL2302. Quantitative RT-PCR showed increased expression of sacol2302 in APT grown with oxacillin (>6-fold compared with COL). Overexpression of sacol2302 in COL to levels consistent with APT (+ oxacillin) did not influence biofilm formation or β-lactam resistance. Proteomics using iTRAQ and LC-MS/MS identified 1323 proteins (∼50% of the theoretical S. aureus proteome), and cluster analysis demonstrated elevated APT abundances of LCP proteins, capsule and peptidoglycan biosynthesis proteins, and proteins involved in wall remodelling. Adaptation to oxacillin also induced urease proteins, which maintained culture pH compared to COL. These results show that S. aureus modifies surface architecture in response to antibiotic adaptation.
School of Molecular Bioscience, ‡Discipline of Pathology, School of Medical Sciences, and §School of Biological Sciences, The University of Sydney , New South Wales 2006, Australia.
Nestor
N
Solis
Benjamin L
BL
Parker
Stephen M
SM
Kwong
Gareth
G
Robinson
Neville
N
Firth
Stuart J
SJ
Cordwell
D000222:Adaptation, Physiological / Q000187:drug effects; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016667:Bacterial Capsules / Q000187:drug effects / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D018441:Biofilms; D052978:Disk Diffusion Antimicrobial Tests; D006863:Hydrogen-Ion Concentration; D010068:Oxacillin / Q000494:pharmacology*; D010403:Penicillin Resistance; D059748:Proteolysis; D020543:Proteome / Q000302:isolation & purification / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects / Q000378:metabolism*; D014357:Trypsin / Q000737:chemistry
D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D020543:Proteome; D014357:Trypsin; D010068:Oxacillin