Fig. 4
Confirmation of key virulence factors of N. farcinica. a Cytotoxicity of wild-type and mutant strains to A549 cells was detected. A549 cells were infected with bacteria at an MOI of 10:1 for 8 h, and the culture supernatant was used to detect the LDH content (Student’s two-tailed T test, *p<0.05, error bars represent SD). b The bacterial load in the lungs of mice infected with wild-type and mutant strains 2 days post-infection. Mice were infected with bacteria intravenously at a dose of 5×106 CFU in 100 μl PBS, lungs were separated, and bacterial colonies in the lungs were counted 2 days after infection (Student’s two-tailed T test, *p<0.05, error bars represent SD). c Mice were intravenously infected with wild-type or mutant Nocardia at a dose of 3×107 CFU in 100 μl PBS, and the survival of mice was monitored for 10 days