The Effect of Anti-Amoebic Agents and Ce6-PDT on Acanthamoeba castellanii Trophozoites and Cysts, In Vitro.

Abstract

Purpose:

The purpose of this study was to analyze the concentration-dependent effects of biguanides (polyhexamethylene biguanide [PHMB], chlorhexidine [CH]); diamidines (hexamidine-diisethionate [HD], propamidine-isethionate [PD], dibromopropamidine-diisethionate [DD]); natamycin (NM); miltefosine (MF); povidone iodine (PVPI), and chlorin e6 PDT on Acanthamoeba trophozoites and cysts, in vitro.

Methods:

Strain 1BU was cultured in peptone-yeast extract-glucose medium. Trophozoites or cysts were cultured in PYG medium containing each agent at 100%, 50%, and 25% of maximum concentration for 2 hours. The percentage of dead trophozoites was determined using a non-radioactive cytotoxicity assay and trypan blue staining. Treated cysts were also maintained on non-nutrient agar Escherichia coli (E.coli) plates and observed for 3 weeks.

Results:

All tested drugs displayed significant cytotoxic effects on 1BU cells based on the biochemical and staining-based viability assays tested. On non-nutrient agar E. coli plates, neither trophozoites nor freshly formed cysts were observed after PHMB, PD, NM, and PVPI treatment, respectively, within 3 weeks. However, CH-, HD-, DD-, and MF-treated cysts could excyst, multiply, and encyst again.

Conclusions:

The off-label drugs PHMB, PD, NM, and PVPI are under in vitro conditions more effective against strain 1BU than CH, HD, DD, and MF. Our findings also suggest that the non-nutrient agar E.coli plate assay should be considered as method of choice for the in vitro analysis of the treatment efficacy of anti-amoebic agents.

Translational Relevance:

Ophthalmologists may optimize the treatment regime against Acanthamoeba keratitis by pre-testing the in vitro susceptibilities of the Acanthamoeba strain against drugs of interest with the non-nutrient E.coli agar plate assay.

• Authors: Lei Shi, Vithusan Muthukumar, Tanja Stachon, Lorenz Latta, Mohamed Ibrahem Elhawy, Gubesh Gunaratnam, Erika Orosz, Berthold Seitz, Albrecht F Kiderlen, Markus Bischoff, Nóra Szentmáry
• Journal: Translational vision science & technology (Transl Vis Sci Technol) Vol. 9 Issue 12 Pg. 29 (11 2020) ISSN: 2164-2591 [Print] United States
• PMID: 33262903 (Publication Type: Journal Article)
• Copyright: Copyright 2020 The Authors.

Chemical References

• Amebicides
• Triazenes
• 1-phenyl-3,3-dimethyltriazene

Topics

• Acanthamoeba castellanii (drug effects)
• Amebicides (pharmacology)
• Animals
• Escherichia coli
• Triazenes
• Trophozoites