Fig 3. Effect of strain competition on the invasion efficiency of L. monocytogenes strains.

Invasion efficiency (%) of L. monocytogenes strains (A) PL25-Rif^R, (B) C5-Str^R, (C) ScottA-Str^R/Rif^R and (D) 6179-Rif^R grown alone (single) or in the presence of a second L. monocytogenes strain (1 day, 10°C, TSB-Y) was determined using Caco2 cells. Cells were infected for 1h with bacteria (multiplicity of infection of 25), and incubated for 45min (invasion) with gentamycin. Data, represented as % of invasion, are mean values ± standard deviation of three biological replicates performed in triplicate. *indicates significant difference of the mixed culture compared to the corresponding single culture (P<0.05). p-values are shown in S3 Table.