Fig. 8

Selective inhibition of A. baumannii by ACD in an in-vitro infection model co-cultured with Calu-6 cells. (a) Flow cytometry analysis of Calu-6 cells and A. baumannii treated with increasing concentrations of ACD for 3 h. The viability of Calu-6 cells remains unaffected across all concentrations of ACD, while the percentage of dead A. baumannii bacteria increases with higher concentrations of the peptide. (i) The infected model (no treatment) presents a certain level of A. baumannii viability. (ii) Application of 20 µg/mL ACD initiates a reduction in A. baumannii viability. (iii) Increasing the concentration to 60 µg/mL ACD continues to maintain a similar reduction in viability as seen with the 20 µg/mL dosage. (iv) With a higher concentration of 100 µg/mL ACD, there is a significant decrease in A. baumannii viability, indicating a heightened bacterial death rate with increased ACD concentration. (b) Quantitative chart representing the viability of Calu-6 cells and A. baumannii bacteria treated with different concentrations of ACD (20, 60, and 100 µg/mL). No statistically significant difference is observed in Calu-6 cell viability across all treatment groups. However, significant differences are observed in A. baumannii viability when treated with ACD concentrations of 20 µg/mL (p-value: 0.037), 60 µg/mL (p-value: 0.044), and 100 µg/mL (p-value: <0.001) compared to the control. The results are based on three separate trials, with three replicates for each variation. ***P ≤ 0.001, **0.001 > P < 0.01, *0.01 > P < 0.05 (one-way ANOVA, significant difference from the control group).