Figure 8

Nicotine treatment inhibits S. aureus invasion in A549 epithelial cells. Cell monolayers was infected with a bacterial multiplicity of infection (MOI) of 10:1. After 2 h of incubation, 200 μg/mL Gentamicin and 40 μg/mL Lysostaphin was added to kill the bacteria external to the monolayer cells at 37 °C in 5% CO₂ for 30 min. Then the monolayer cells were subsequently lysed with 200 μL 0.1% Triton X-100 for 20 min at room temperature, and were then diluted with PBS and plated on TSB-agar plates to determine the number of intracellular bacteria. Intracellular CFUs in nicotine treated group and control group were 3.360 ± 0.25 log¹⁰ and 1.816 ± 0.08 log¹⁰ respectively. (n = 3, p < 0.05) Data were represented as mean ± SD of three independent experiments. *P < 0.05.