Abstract
Purpose :
To evaluate the anti-amoebic activity of the antimicrobial peptide mimic RK-7 against Acanthamoeba trophozoites (infective form) in comparison with chlorhexidine.
Methods :
Acanthamoeba amoebicidal, amoebistatic and encystation assays were performed using protocols described in literature. The activity of peptide mimic RK-7 was compared with chlorohexidine against the Acanthamoeba castellanii 044 with concentrations of both ranging from 125µM to 7.81µM. All experiments are performed in duplicate with three independent replicates. Data was represented as mean ± SE and analysed using two sample t-test and two tailed distributions. p < 0.05 is considered as statistically significant.
Results :
In amoebicidal assays, both RK-7 and chlorhexidine reduced the numbers of trophozoites by 50% at concentrations ranging from 125 to 15.6 µM, with no difference between activities (p>0.05). Similarly,amoebistatic assays showed concentrations between 125 to 7.81 µM prevented the growth of trophozoites by between 100-82% for RK-7 and 100-97% for chlorhexidine (p>0.05). In the encystment assay, both RK-7 and chlorhexidine inhibited cyst formation by 70% at the lowest test concentration i.e., 7.81 µM. Inhibition of cyst formation at concentrations 62.5 µM and 15.6 µM by chlorhexidine (97% and 86% reduction) was greater (p=0.025 and p=0.04) than RK-7 (84% and 71% reduction).
Conclusions :
RK-7 peptide mimic showed excellent anti-amoebic activity against Acanthamoeba castellanii 044. Future experiments will evaluate the activity of peptide mimic coated onto contact lens against Acanthamoeba spp.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.