Galleria mellonella larvae infection model

To detect whether the virulence of phage-resistant mutants was attenuated, we used the G. mellonella (wax moth) larvae infection model, which has been widely used in bacterial virulence assay^47,48. Briefly, 16 larvae of 250–350 mg in weight (Huiyude; Tianjin, China) were randomly selected for each group. Strain B0, P24-resistant mutants (B1-1, B1-2, and B1-3), P39-resistant mutants (B2-1, B2-2, and B2-3), and two transformants (B1-1::pmshA, and B1-2::pwcaJ, see below for detailed information) were washed using phosphate-buffered saline (PBS; Beyotime, Shanghai, China) and were adjusted to 0.5 McFarland (around 10⁸ CFU/mL). We injected 10 μL bacterial cultures (10⁶ CFU) into each larvae using a microsyringe (Gaoge; Shanghai, China), while larvae injected with PBS alone were used as negative controls. The larvae were then incubated at 37 °C, and the number of dead larvae was recorded at 12-h intervals up to 72 h. Larvae death is defined by the complete absence of movement under repeated agitations.