Figure 4.

Synergistic anti-infective effect of PMAP-36 in combination with tetracycline against E. coli infection in vivo. Mice were intraperitoneally infected with PCN033 (1 × 10⁷ CFU) and then treated with tetracycline, PMAP-36, or PMAP-36 in combination with tetracycline. The infected mice treated with PBS were used as controls. The mice that survived at 72 h post-infection are shown (n = 10/group) (A). The bacterial burden in the liver, spleen, lung, blood, and peritoneal lavage fluid (PLF) was determined (n = 5/group) (B). Haematoxylin and eosin staining of the lung at 12 h post-infection was performed (original magnification × 400) (C). Images are representative of those of three mice from each group. Statistical significance is indicated by *p < 0.05, **p < 0.01, and ***p < 0.001 (Student’s t test).