Invasion and proliferation indexes of wild-type and mutant strains infecting HeLa epithelial cell cultures.

Footnotes. *Percentage of bacteria invading HeLa cells in 20 min and surviving the gentamicin protection assay. Viable counts were seeded at 2 h p.i. Values are normalized according to the wild-type strain (0.76±0.211). ‡Viable intracellular bacteria at 24 h p.i. versus viable intracellular bacteria at 2 h p.i. All results are the mean value of triplicates of three independent experiments. #Significant values compared to the wild-type strain (p<0.05). ND: Not detected in any of the experiments.