Figure 5.

Invasion and intracellular survival in differentiated neutrophils and biofilm production of clinical isolates. Capacity of S. aureus clinical isolates to (A) invade neutrophils and survive intracellular and (B) form biofilm. (A) For measurements of invasion and intracellular survival, differentiated HL-60 were incubated with S. aureus at a MOI of 100 2h at 37°C. Extracellular bacteria were killed using gentamicin and cells were lysed to detect intracellular bacteria following incubation for 1h to allow intracellular killing. The outliers are isolates B3 and D6. Results of three independent experiments. (B) Biofilm formation was measured using a crystal violet stain, experiments performed as triplicates. The comparison of two data groups were analyzed by Mann– Whitney U test (one-tailed, confidence intervals 95%) with ***P < 0.001.