|Foster frey, Juli|
Submitted to: Evergreen International Phage Meeting
Publication Type: Abstract only
Publication Acceptance Date: 6/17/2009
Publication Date: 8/11/2009
Citation: Becker, S.C., Foster Frey, J.A., Willard, R.R., Lease, R.A., Almeida, R., Marriott, I., Dong, S., Baker, J.R., Pritchard, D.G., Donovan, D.M. 2009. Peptidoglycan hydrolase fusion to protein transduction domains kill intracellular staphylococci. Evergreen International Phage Meeting. Interpretive Summary: n/a
Technical Abstract: Staphylococci and streptococci are both human and agricultural pathogens that are demonstrating an increasing frequency of antibiotic resistant strains resulting in chronic infections. The rise in bacterial resistance to antibiotics world-wide has precipitated the search for alternatives to broad range antimicrobials, and specifically those that are refractory to resistance development. Peptidoglycan hydrolases (including bacteriophage endolysins) are one such group of novel antimicrobials. These enzymes cause cell lysis by degrading cell wall peptidoglycan, are often genus specific, and no bacteria have been identified that can evade lysis by their bacteriophage endolysin (despite efforts to identify them). Lysins are modular in structure, often with multiple lytic domains and a cell wall binding domain. We have shown that fusing the active domains from multiple endolysins generates chimeric molecules that maintain their parental specificities and lytic activities. We have also created fusion antimicrobials that each lyse staphylococci with three unique and synergistic lytic activities. Because no bacterium can resist three simultaneous lytic activities, we predict these fusions will be refractory to resistance development. We have collated, and compared all staphylococcal SH3b cell wall binding domains, and through heterologous fusion to a streptococcal endolysin lytic domain, have demonstrated the relative efficacy of bacteriocin- and endolysin-derived cell wall binding domains. The staphylococcal cell wall binding domains can re-direct the streptococcal lytic domain to kill S. aureus, with a 10X increase in lytic activity over the wild type streptococcal enzyme activity. The resultant heterologous fusion also maintains a high level of anti-streptococcal lytic activity, indicating that the SH3b domain is not the only factor that contributes to lytic specificity. Targeting of intracellular staphylococcal pathogens with fusions to eukaryotic protein transduction domains or cell penetrating peptides has been achieved in mammary epithelial cells and osteoblasts suggesting that peptidoglycan hydrolase fusions are a potential therapeutic for chronic staphylococcal (MRSA) infections.