title: Synergism between a novel chimeric lysin and oxacillin protects against infection by methicillin-resistant Staphylococcus aureus.
abstract: Staphylococcus aureus is the causative agent of several serious infectious diseases. The emergence of antibiotic-resistant S. aureus strains has resulted in significant treatment difficulties, intensifying the need for new antimicrobial agents. Toward this end, we have developed a novel chimeric bacteriophage (phage) lysin that is active against staphylococci, including methicillin-resistant S. aureus (MRSA). The chimeric lysin (called ClyS) was obtained by fusing the N-terminal catalytic domain of the S. aureus Twort phage lysin with the C-terminal cell wall-targeting domain from another S. aureus phage lysin (phiNM3), which displayed Staphylococcus-specific binding. ClyS was expressed in Escherichia coli, and the purified protein lysed MRSA, vancomycin-intermediate strains of S. aureus (VISA), and methicillin-sensitive (MSSA) strains of S. aureus in vitro. In a mouse nasal decolonization model, a 2-log reduction in the viability of MRSA cells was seen 1 h following a single treatment with ClyS. One intraperitoneal dose of ClyS also protected against death by MRSA in a mouse septicemia model. ClyS showed a typical pattern of synergistic interactions with both vancomycin and oxacillin in vitro. More importantly, ClyS and oxacillin at doses that were not protective individually protected synergistically against MRSA septic death in a mouse model. These results strongly support the development of ClyS as an attractive addition to the current treatment options of multidrug-resistant S. aureus infections and would allow for the reinstatement of antibiotics shelved because of mounting resistance.
authors.affiliation: The Laboratory of Bacterial Pathogenesis and Immunology, The Rockefeller University, 1230 York Ave., Box 172, New York, NY 10065, USA. vaf@rockefeller.edu
authors.forename: Anu
authors.initials: A
authors.lastname: Daniel
authors.forename: Chad
authors.initials: C
authors.lastname: Euler
authors.forename: Mattias
authors.initials: M
authors.lastname: Collin
authors.forename: Peter
authors.initials: P
authors.lastname: Chahales
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Gorelick
authors.forename: Vincent A
authors.initials: VA
authors.lastname: Fischetti
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage*; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics; D004195:Disease Models, Animal; D004357:Drug Synergism; D005260:Female; D005814:Genes, Viral; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D046529:Microscopy, Electron, Transmission; D010068:Oxacillin / Q000008:administration & dosage*; D015202:Protein Engineering; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics; D018805:Sepsis / Q000188:drug therapy / Q000382:microbiology; D013203:Staphylococcal Infections / Q000188:drug therapy* / Q000382:microbiology*; D013204:Staphylococcus Phages / Q000235:genetics; D013211:Staphylococcus aureus / Q000821:virology; D014640:Vancomycin / Q000008:administration & dosage; D014764:Viral Proteins / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D017931:DNA Primers; D004279:DNA, Viral; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D014640:Vancomycin; D010068:Oxacillin