STAPHYLOCOCCUS HAEMOLYTICUS PROPHAGE PhiSH2 ENDOLYSIN IS LYTIC FOR STAPHYLOCOCCUS AUREUS

摘要

Methicillin-resistant (MRSA) and multi-drug resistant strains of Staphylococcus aureus are becoming increasingly prevalent in both human and veterinary clinics. S. aureus- causing bovine mastitis yields high annual losses to the dairy industry. Treatment of mastitis by broad range antibiotics is often not successful and may contribute to development of antibiotic resistance. Bacteriophage endolysins are a promising new source of antimicrobials. The endolysin of prophage PhiSH2 of Staphylococcus haemolyticus strain JCSC1435 (PhiSH2 lysin) shows lytic activity against live staphylococcal cells. Deletion constructs were tested in zymograms and turbidity reduction assays to evaluate the contribution of each functional module to lysis. The CHAP domain exhibited three-fold higher activity than the full length protein. Activity was further enhanced in the presence of bivalent calcium ions. The full length enzyme and the CHAP domain showed activity against multiple staphylococcal strains, including MRSA strains, mastitis isolates, and coagulase negative staphylococcal (CoNS) strains.