• Confirmation of vaccine candidate expression in multiple Staphylococcus aureus strains

      Muench, Anna Rachael; Shirtliff, Mark (2012)
      Staphylococcus aureus has emerged as an important pathogen due to its ability to form persistent infections through the biofilm mode of growth. S. aureus is responsible for thousands infections per year, which include a vast array of diseases and is rapidly developing the ability to become antibiotic resistant resulting in failure of our current methods of treatment. This antibiotic resistance is increased during biofilm formation when the bacteria form a polysaccharide matrix, which prevents infection clearance through antimicrobial means or by the host immune response. This project analyzed 14 Staphylococcus aureus strains and one Staphylococcus epidermidis strain obtained from NARSA (Network on Antimicrobial Resistance in Staphylococcus aureus) detecting the genomic presence and expression of three previously identified immunogenic proteins - glucosaminidase, SA0486 (a hypothetical lipoprotein), and SA0688 (an ABC transporter lipoprotein) - which have been incorporated into a vaccine described by Brady et al 2011. The strains were analyzed for the presence of the three specific genes through PCR and gel electrophoresis and for the expression of these proteins under biofilm growth conditions through western blot analysis. All strains contain the genetic code for these antigens and express at least 2 of the 3 antigens under biofilm growth conditions. Two strains were further analyzed for expression of these antigens under planktonic growth at 2.5hrs, 5hrs, and 24hrs comparing them to biofilm growth utilizing western blot analysis. These strains showed varying expression of the antigens under planktonic conditions with SA0688 expressed under all growth conditions in both strains, glucosaminidase with a gradual increase in expression as growth time increase in both strains, and SA0486 showing different expression patterns in the two strains but with the highest level at 5hrs and 24hrs. To truly understand the expression patterns under planktonic growth, further analysis will be required. The data generated provided the evidence of the universal nature of the vaccine previously developed in the Shirtliff laboratory described in Brady et al 2011.