Figure 4.

PST is more potent than фA1122 in the presence of blood. Phage-based lysis assays were performed with the bioluminescent Y. pestis strain EV76-lux (10⁷ CFU/mL) suspended in BHI broth (blue and orange lines) or in mouse whole blood (gray and red lines). The Y. pestis strain was infected with фA1122 (A) or PST (B) phages (10⁶ PFU/mL; multiplicity of infection (MOI) = 0.01). Bioluminescence (RLU) was measured at 37 °C in 15 min intervals for 24 h using a SPARK 10M plate reader. The experiment was performed in biological duplicates (using blood pooled from three mice for each experiment), and the results are representative of one experiment. Presented values are the average results from three wells in a single triplicate experiment, and the error bars represent the standard deviations (SD). The green line represents the background from BHI broth. G.C. = growth control.