Adherence and invasion assays. STEC were uninfected or infected with PCV2 for 24 h, 36 h and 48 h before incubating with SS2 at MOI 10. The adherent and invasive bacteria was compared with the input number. A Rates of SS2 adherence to STEC. B The invasion rates of SS2 recovered from invaded STEC. The results are shown as mean ± SD of five independent experiments. Significant differences were determined using Student t-test. **P < 0.01; ***P < 0.001; ns: not significant.