Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/17/2013
Publication Date: 5/28/2013
Citation: Rodriguez-Rubio, L., Martinez, B., Rodriguez, A., Donovan, D.M., Götz, F., García, P. 2013. Undetectable bacterial resistance to phage lytic proteins from the Staphylococcus aureus bacteriophage vB_SauS-phiIPLA88. PLoS One. 8(5):e64671. Interpretive Summary: Problem-- In this age of multi-drug resistant Staphylococcus aureus (and other pathogens) in both human and animal infectious disease, there is a need for novel antimicrobials that are refractory to reistance development. Accomplishment-- By fusing staphylococcal bacterial cell wall degrading peptidoglycan hydrolase enzymes into one fusion construct, we have generated antimicrobial enzymes that have multiple simultaneous, unique activities and are thus highly refractory to resistance development. Contribution of Accomplishment to Solving the Problem—This work still needs verification in animal models of infectious disease, but is the first step toward commercializing our novel antimicrobials. Once commercialized, this will eventually benefit both human and animal health care workers to avoid and cure multi-drug resistant staphylococcal diseases.
Technical Abstract: The increase in antibiotic resistance world-wide revitalized the interest in the use of phage lysins to combat pathogenic bacteria. In this work, we tested for the emergence of resistant Staphylococcus aureus to any of three phage lytic proteins constructs. The investigated cell wall lytic enzymes were the endolysin LysH5 derived from the S. aureus bacteriophage vB_SauS-phi-IPLA88 (phi-IPLA88) and two fusion proteins between lysostaphin and the virion-associated peptidoglycan hydrolase HydH5 (HydH5SH3b and HydH5Lyso). Resistant S. aureus could not be identified after 10 cycles of bacterial exposure to phage lytic proteins in both liquid and plate culture methods. However, a rapid increase in lysostaphin resistance (up to 1000-fold in liquid culture) was observed. The lack of resistant development could be due to the bifunctional catalytic domains present in the phage lytic proteins from phiIPLA88. To support this hypothesis, the specific cleavage sites on the staphylococcal peptidoglycan were analyzed for each protein. The bifunctional phage lytic proteins may have a therapeutic potential to treat staphylococcal infections.