Fig. 2

Schematic diagram of experimental in vitro set-ups. In the pre-incubation set-up, live bacteria and virus were pre-incubated for 1 h at 37 °C, before being incubated with the mammalian cells for 1 h. In the pre-treatment set-up, the mammalian cells were incubated with live bacteria for 1 h, washed with PBS and infected with virus for 1 h. In the co-treatment set-up, live bacteria were added to the cells at the same time of virus infection for 1 h. In the post-treatment set-up, the mammalian cells were infected with virus for 1 h, then washed with PBS and incubated with live bacteria for another hour. In all four set-ups, 50 μg/ml gentamicin-supplemented maintenance media was eventually added to the cell monolayers. Sample supernatants were harvested 12 or 24 h post-infection and plaque assay was performed using RD cells to determine the viral titer