PCR Assay for Rapid Taxonomic Differentiation of Virulent Staphylococcus aureus and Klebsiella pneumoniae Bacteriophages

Phage therapy is now seen as a promising way to overcome the current global crisis in the spread of multidrug-resistant bacteria. However, phages are highly strain-specific, and in most cases one will have to isolate a new phage or search for a phage suitable for a therapeutic application in existing libraries. At an early stage of the isolation process, rapid screening techniques are needed to identify and type potential virulent phages. Here, we propose a simple PCR approach to differentiate between two families of virulent Staphylococcus phages (Herelleviridae and Rountreeviridae) and eleven genera of virulent Klebsiella phages (Przondovirus, Taipeivirus, Drulisvirus, Webervirus, Jiaodavirus, Sugarlandvirus, Slopekvirus, Jedunavirus, Marfavirus, Mydovirus and Yonseivirus). This assay includes a thorough search of a dataset comprising S. aureus (n = 269) and K. pneumoniae (n = 480) phage genomes available in the NCBI RefSeq/GenBank database for specific genes that are highly conserved at the taxonomic group level. The selected primers showed high sensitivity and specificity for both isolated DNA and crude phage lysates, which permits circumventing DNA purification protocols. Our approach can be extended and applied to any group of phages, given the large number of available genomes in the databases.