Phage Propagation and Purification

Host bacterial isolates were plated on Difco^TM nutrient agar (NA) (BD, Sparks, Maryland, USA) from frozen stock (Microbank^TM, ProLab Diagnostics, Richmond Hill, ON, Canada), and then the phage were propagated as previously described [13 (link)]. Briefly, two bacterial cultures were prepared in Difco^TM nutrient broth (NB) (BD, Sparks, MD, USA): 0.9 mL at 10⁸ CFU/mL in a 2 mL microcentrifuge tube and 100 mL at 10⁶ CFU/mL in a 250 mL beveled flask. A 100 µL aliquot of phage stock solution (~10⁸ PFU/mL) was then added to the 0.9 mL culture. Both cultures were incubated at 27 °C (165 rpm) in a Innova 44 shaking incubator (New Brunswick Scientific, Edison, NJ, USA). After 4 h, the contents of the 2 mL tube were transferred into the beveled flask and incubation continued overnight. The phage solution was then treated with chloroform, centrifuged, and passed through a 0.22 µm filter (Millipore, Billerica, MA, USA). The resulting phage stocks were stored in amber vials (Wheaton Industries, Millville, NJ, USA) with 1 mL of chloroform at 4 °C. All phages and bacteria hosts used in this study can be found in Table 2.