Fig. 4.

Plaque sizes of L. monocytogenes strains in the BoMac and CaCo-2 cell lines. Results are shown relative to the internal control strain L104. a: The relative plaque size in BoMac-cells is shown for each strain as an aligned dot plot. Red: Complex A strains; green: Complex C strains; blue: Complex B strains. The horizontal line indicates the mean. b: Box plots comparing plaque size in BoMac cells between complex A and complex C strains. Plaques of complex A strains are significantly larger than those of complex C strains. The horizontal line represents the median, + is the mean. c: The host species had no influence on plaque-size in BoMac cells. d: CaCo-2 cells: the relative plaque size for each strain is shown as an aligned dot plot. Red: Complex A; green: Complex C; blue: Complex B. The horizontal line indicates the mean. e: Box plots comparing plaque size in CaCo-2 cells between complex A and complex C strains. There is no difference in plaque size between complex A and C strains. f: Human strains formed larger plaques in CaCo-2 cells than strains isolated from small ruminants. * = p < 0.05. Box plots: Whiskers represent maxima and minima. The horizontal line represents the median, + is the mean