Figure 1
Comparison of the bacterial virulence corresponding to strains ST121 and ST96 against different in vitro cell populations: erythrocytes, PMN and macrophages. A Haemolytic assays towards 8% rabbit RBC. OD 450 nm was read to determine the haemolytic capacity of the supernatant from strains ST121 and ST96. B, C PMN lysis assays and macrophage lysis assays. The supernatants of strains ST121 and ST96 were added to 2 × 106 neutrophils/mL or 3 × 105 macrophages/mL, respectively, and incubated for 30 min at 37 °C. Later the LDH release assay was performed for the quantification of cell death and cell lysis. OD optical density, LDH: lactate dehydrogenase, PMN polymorphonuclear leukocytes, RBC red blood cells. ■Average results of three ST96 strains and ■Average results of three ST121 strains. The experiments were performed in triplicate. Bars represent the obtained least square means and error bars show their corresponding standard error. *Statistically significant differences (P < 0.05).