Characterization and genomic analysis of a novel bacteriophage against methicillin-resistant staphylococcus aureus

Çotak, Medine
Methicillin resistant Staphylococcus aureus (MRSA) is one of the most frequent hospital and community acquired infectious agents causing severe diseases. Bacteriophages may offer a solution to treat the bacterial infections that are not responding to classical antibiotics. In this context, a new lytic phage, named as vB_SauM-MikSA913, was isolated from sewage treatment center in Samsun (Turkey). MRSA clinical strains obtained from a local hospital were used as propagating hosts while searching for the lytic phages. Genomic analysis suggest that the isolated vB_SauM-MikSA913 belongs to the Myoviridiae family like the most characterized phage K. Phage vB_SauM-MikSA913 has a genome size of 134193 bp double-stranded DNA, encoding 206 open reading frames (ORFs) and 4 tRNAs. There was a high similarity between our phage to others described in the literature such as qdsa002, GH15, vB_Sau_CG, and phiSA039 with more than 90% query cover and identity. vB_SauM-MikSA913 (shortly called MikSA913) has a wide range of host and high lytic activity on MRSA strains. The bacteriolytic activity of the phage was tested over a range of multiplicity of infection (MOI) and the optimal MOI was found to be 0.001, which indicates its good lytic efficiency even at low concentration. MikSA913 was stable at a wide range of pH and temperatures. One-step growth curve analysis showed that the eclipse and latent periods of MikSA913 was 15 min and 20 min, respectively and the burst size is 112 plaque forming units/infected cell. Bacteriophage therapy is now seriously on the table as an alternative treatment to combat with antibiotic resistance crisis. The high lytic activity, its wide host range and lack of virulence factors and antibiotic resistance genes deduced from bioinformatics analysis suggest that the phage vB_SauM-MikSA913 could be an option for treating S.aureus infections including MRSA infections.
Citation Formats
M. Çotak, “Characterization and genomic analysis of a novel bacteriophage against methicillin-resistant staphylococcus aureus,” Ph.D. - Doctoral Program, Middle East Technical University, 2019.