Fig 2: Defective adhesion and invasion of the ΔsurA and ΔlpcA mutants compared with uropathogenic E. coli UTI89 in bladder epithelial cells. (A) The adhesion ability of mutant strains. (B) The invasive capability of mutant strains. The human epithelial cells (ATCC HTB-9) (2 × 106 cell/well) were infected with log-phase E. coli UTI89 and its mutants ΔsurA and ΔlpcA in a multiplicity of infection (m.o.i.) of 5~10 per cell in 24-well plate. At 2 h post infection, the adhesion and invasion frequencies were analyzed as described in Methods. The experiments were done in triplicates and repeated for three times. The results are expressed as means ± SD. *p < 0.05, relative to UTI89 group. **p < 0.01, relative to UTI89 group.

Fig 3: Effect of berberine on E. coli strains invasion ability against 5637 ATCC (HTB-9) cell line. Black histograms: strains not treated with berberine. Light grey histograms with large squares: strains pre-treated with 1/2 MIC berberine. Light grey histograms with small squares: strains pre-treated with 1/4 MIC berberine. Dark grey histograms with wide lines: strains co-incubated with 1/2 MIC berberine. Dark grey histograms with narrow lines: strains co-incubated with 1/4 MIC berberine. (a) E. coli ATCC 11775. (b) E. coli DSM 22312. (c) E. coli (CA-UTI) CL1. (d) E. coli CL2 (CA-UTI). Results are expressed as CFU/well. The bars represent means ± SD of three independent experiments performed in triplicate. Statistically significant differences, determined by one-way analysis of variance ANOVA (* indicates a significant difference at p < 0.05 versus control/untreated, ** indicates a significant difference at p < 0.01 versus control/untreated).