| dc.description.abstract | Swine farm environments are a reservoir for Staphylococcus aureus and therefore may also be a reservoir for S. aureus phages. The diversity and ecology of these phages has not been investigated previously. Phage isolated from swine environments could potentially be used to control S. aureus in swine environments or used for phage therapy for human S. aureus infections. The objective of this work was to 1) determine the prevalence of S. aureus phages in swine environments across the United States; 2) isolate and characterize phages by restriction digestion of gDNA, morphological classification and host range; 3) examine the genomic diversity of isolated phages in comparison to each other and well-known S. aureus phages.
20 swine farms from across the US were sampled for the prevalence of S. aureus phages. One location was sampled in-depth at two different time points, six months apart. Of the 19 farms sampled only once, 12 farms (63%) were positive for phage capable of infecting at least one of the ten S. aureus host strains used during enrichment. These enrichment panels included S. aureus strains relevant to human health and recently acquired swine nasal isolates from across the US.
Of the virulent phages tested in this study, Podoviridae displayed the narrowest host ranges and Myoviridae, both K-like and Mars Hill-like, displayed the widest range. Both types of Myoviridae were also able to infect strains of S. pseudintermedius and S. epidermidis although this ability was very strain specific. Overall, twenty-six isolated phage were sequenced, with four of them having genomes of ~44 kb, seventeen with ~18 kb, one with ~141 kb and four with ~ 270 kb.
The genomic diversity among isolated Podoviridae and Siphoviridae was low. However, one type of Myoviridae with ~ 270 kb genomes (Mars Hill-like) represent a new type of S. aureus phage. These results show that S. aureus phages are prevalent within swine environments in the US. Additionally, the characterization of these phages provides new insights into the diversity of S. aureus phages and the possible application they may have for controlling S. aureus in swine environments or for phage therapy in human medicine. | en |
