Inactivation of Acanthamoeba Cysts in Suspension and on Contaminated Contact Lenses Using Non-Thermal Plasma.

Tereza Měřínská,Josef Khun,Vladimír Scholtz,Eva Nohýnková,Jaroslav Julák

doi:10.3390/microorganisms9091879

Abstract

Water suspensions of cysts of a pathogenic clinical isolate of Acanthamoeba sp. were prepared, and the cysts were inactivated either in suspension or placed on the surface of contact lenses by the non-thermal plasma produced by the DC corona transient spark discharge. The efficacy of this treatment was determined by cultivation and the presence of vegetative trophozoites indicating non-inactivated cysts. The negative discharge appeared to be more effective than the positive one. The complete inactivation occurred in water suspension after 40 min and on contaminated lenses after 50 min of plasma exposure. The properties of lenses seem to not be affected by plasma exposure; that is, their optical power, diameter, curvature, water content and infrared and Raman spectra remain unchanged.

Highlights

The genus Acanthamoeba represents free-living amoebae, distributed worldwide and isolated from most environmental niches, e.g., soil, dust, air, seawater and fresh water and plants
Acanthamoebae are considered to be the most common free-living eukaryotic microorganisms. They have two stages in their life cycle: (1) the metabolically active, motile trophozoite stage and (2) the dormant cyst stage [1]. Under stressful conditions, such as starvation and environmental extremes, the trophozoite converts to the cyst, which can survive for years [2,3]
Cysts are responsible for the extraordinary resistance of acanthamoebae to drugs and disinfectants [4] as well as for persistent and/or recrudescent infections: in infected tissues, they survive for months

Summary

Introduction

The genus Acanthamoeba represents free-living amoebae, distributed worldwide and isolated from most environmental niches, e.g., soil, dust, air, seawater and fresh water and plants. Acanthamoebae are considered to be the most common free-living eukaryotic microorganisms. They have two stages in their life cycle: (1) the metabolically active, motile trophozoite stage and (2) the dormant cyst stage [1]. Under stressful conditions, such as starvation and environmental extremes, the trophozoite converts to the cyst, which can survive for years [2,3]. Cysts are responsible for the extraordinary resistance of acanthamoebae to drugs and disinfectants [4] as well as for persistent and/or recrudescent infections: in infected tissues, they survive for months (for review, see [5])

Methods

Results

Conclusion