%0 Journal Article %T Antistaphylococcal activity of bacteriophage derived chimeric protein P128 %A Aradhana A Vipra %A Srividya Desai %A Panchali Roy %A Raghu Patil %A Juliet Raj %A Nagalakshmi Narasimhaswamy %A Vivek Daniel Paul %A Ravisha Chikkamadaiah %A Bharathi Sriram %J BMC Microbiology %D 2012 %I BioMed Central %R 10.1186/1471-2180-12-41 %X Here we report results of in vitro studies evaluating the susceptibility of staphylococcal strains to this novel protein.Using the broth microdilution method adapted for lysostaphin, we found that P128 is effective against S. aureus clinical strains including MRSA, methicillin-sensitive S. aureus (MSSA), and a mupirocin-resistant S. aureus. Minimum bactericidal concentrations and minimum inhibitory concentrations of P128 (1-64 ¦Ìg/mL) were similar across the 32 S. aureus strains tested, demonstrating its bactericidal nature.In time-kill assays, P128 reduced colony-forming units by 99.99% within 1 h and inhibited growth up to 24 h.In an assay simulating topical application of P128 to skin or other biological surfaces, P128 hydrogel was efficacious when layered on cells seeded on solid media. P128 hydrogel was lethal to Staphylococci recovered from nares of healthy people and treated without any processing or culturing steps, indicating its in situ efficacy. This methodology used for in vitro assessment of P128 as an agent for eradicating nasal carriage is unique.The novel chimeric protein P128 is a staphylococcal cell wall-degrading enzyme under development for clearance of S. aureus nasal colonization and MRSA infection. The protein is active against globally prevalent antibiotic-resistant clinical isolates and other clinically significant staphylococcal species including S. epidermidis. The P128 hydrogel formulation was bactericidal against Staphylococci including S. aureus recovered from the nares of 31 healthy people, demonstrating its in situ efficacy.Antibiotic-resistant Staphylococcus aureus strains emerging from the community as well as hospital environments represent a global threat [1,2], requiring new approaches to control this pathogen. The anterior nare is the major reservoir of S. aureus in humans; 80% of the human population may be carriers [3]. A causal relationship between nasal colonization of S. aureus and serious infection has been established; thu %U http://www.biomedcentral.com/1471-2180/12/41