Susceptibility of Staphylococcus aureus strains to commercial therapeutic phage preparations

OBJECTIVESThe aim of this study was to determine the susceptibility of Staphylococcus aureus strains to commercial phage preparations. The strains were isolated from clinical patients as well as from nasal mucosa of healthy carriers. BACKGROUNDThe elevating number of antibiotic-resistant S. aureus strains present a therapeutic challenge, especially in high-risk patients. One of the promising ways to solve this problem is phage therapy. METHODSSusceptibility of 111 carrier strains of S. aureus (4 strains were methicillin-resistant; MRSA) and 81 clinical isolates from bloodstream or skin and soft tissue infections (28 were MRSA) to four commercial phage preparations was assessed in vitro by spot assay. The clonality of S. aureus strains was determined by spa typing. RESULTSSpa typing revealed 97 distinct spa types. A proportion of 73-80 % of the tested S. aureus strains were revealed to have in vitro phage susceptibility, depending on the clonal affiliation of the strains and phage preparation tested. The susceptibility to phage preparations was significantly higher in MRSA strains (p < 0.001). CONCLUSIONSIn vitro results indicate a promising therapeutic potential of the tested commercial anti-staphylococcal phage preparations. They could be applied to a broad spectrum of bacterial clones, and have an excellent activity especially against MRSA strains (Tab. 2, Fig. 2, Ref. 43).