Fig. 7

Gut-to-lung translocation of antibiotic-resistant E. coli Ec1 in P. aeruginosa-induced pneumonia mice. (A) Experimental design and group assignments for mouse experiments. (B) Quantification of resistant E. coli Ec1 load in stool samples on days 0 and 31, cultured on E. coli chromogenic medium containing 100 mg/L ampicillin in the Cont, Ec, Pa, and EcPa groups (n = 5). (C) Quantification of resistant E. coli Ec1 load in the oral cavity and lung tissues after sacrifice, detected using E. coli chromogenic medium with 100 mg/L ampicillin across experimental groups (n = 5). (D) Representative image of ANI analysis comparing the genomes of resistant E. coli isolated from fecal samples of EcPa mice with the original Ec1 strain (n = 3). (E) Representative image of ANI analysis comparing the genomes of resistant E. coli isolated from lung tissues of EcPa mice with the original Ec1 strain (n = 6). (F-K) ANI analysis comparing resistant E. coli genomes isolated from lungs and fecal samples of EcPa mice, fecal isolates: n = 3, one isolate/mouse, lung isolates: n = 6, two isolates/mouse. (L) Representative H&E-stained lung sections from Cont, Ec, Pa, and EcPa groups. Scale bars = 50 μm (n = 5). (M) Disease activity index scores of lung injury across experimental groups (n = 5). (N) Histological score of lung injury based on H&E staining (n = 5). (O) Quantification of resistant E. coli Ec1 load in the MLNs after sacrifice, detected using E. coli chromogenic medium with 100 mg/L ampicillin across groups (n = 5). Statistics by one-way ANOVA with Tukey’s post-hoc test. Values shown are the mean ± SD. * p < 0.05. ** p < 0.01. Ec1: translocated E. coli