Complete Genome Sequence and Analysis of NHSP6, a Broad-Spectrum Bacteriophage Against <i>Staphylococcus Aureus</i> Isolates of Bovine and Human Origin

Background: Staphylococcus aureus is a major pathogen of animals and humans alike. It is the most important etiological agent associated with subclinical and clinical bovine mastitis, which is a complex, multi-etiological disease with serious economic consequences. In humans, S. aureus is associated with a wide variety of infections, which result in asymptomatic to fulminant outcomes, both in hospitals and in communities. Infections with S. aureus are often challenging to treat owing to its antimicrobial resistance, warranting research on alternatives or adjuncts to antibiotic therapy. One such alternative is the use of bacteriophages. Materials and Methods: We isolated a lytic bacteriophage designated NHSP6 against S. aureus and examined its ultrastructure by transmission electron microscopy. The phage’s tropism was assessed against several S. aureus strains associated with bovine mastitis and human infections and belonging to various sequence types. The complete genome of NHSP6 was elucidated by paired-end sequencing and analyzed using a panel of bioinformatics tools. Results: The NHSP6 phage showed the morphology of a myovirus. Its genome contained a 142,426 bp-long linear dsDNA with a GC content of 30.18%. The genome was predicted to contain 251 coding sequences, including those for 168 hypothetical proteins and 3 tRNAs. Comparative genomic analyses suggested that phage NHSP6 may represent a new species within the genus Kayvirus under the subfamily Twortvirinae , family Herelleviridae , and class Caudoviricetes . Discussion: The bacteriophage NHSP6 could be a valuable biological for developing therapeutics against S. aureus infections in animals and humans.