PLD expression differentially affects adhesion (A) and invasion (B) of A. haemolyticum into HeLa cells. (A) A. haemolyticum strains were added to cell monolayers, with or without 5 mM MβCD or 312 ng HIS-PLD, and allowed to adhere for 2 h at 37°C prior to washing and recovery of cell-associated bacteria. (B) Following adhesion, cell monolayers were washed and incubated for an additional 2 h in the presence of 10 μg/ml gentamicin to kill external bacteria. Adhesion or invasion are shown as a percentage of wild type, which was set to 100%. Error bars indicate one standard deviation from the mean calculated from the averages of at least three independent experiments conducted in triplicate. Statistical significance was calculated using single factor ANOVA and p < 0.05 was considered significant.