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Analysis of the Susceptibility, Prevalence, and Pathogenicity of the Opportunistic Pathogen Acanthamoeba

Shoff, Megan E.
http://rave.ohiolink.edu/etdc/view?acc_num=osu1229352913

Abstract Details

2008, Doctor of Philosophy, Ohio State University, Evolution, Ecology, and Organismal Biology.
The ubiquitous, free-living naked amoeba, Acanthamoeba, is an opportunistic pathogen that can cause the painful eye disease Acanthamoeba keratitis (AK), and, in immunocompromised individuals, the fatal disease granulomatous amebic encephalitis (GAE). AK is a rare corneal disease that effects contact lens wearers more than non-contact lens wearers, though up to 10-15% of cases do occur in non-contact lens wearers. The aims of this work were threefold: 1) to determine the susceptibility of recent clinical and environmental strains of Acanthamoeba to contact lens cleaning solutions and to determine if the inclusion of taurine provided a protective benefit to the amoebae, 2) to determine whether, and to what level, acanthamoebae were present in domestic water in the greater Chicago area and if the amoebae could be linked to the recent outbreak of AK in that area, and 3) to determine if an invertebrate animal model, the grasshopper Schistocerca americana, could be used in initial pathogenicity and virulence studies of Acanthamoeba. A range of strains were examined from both “environmental” sources (domestic water supply) and from clinical samples. Acanthamoebae isolates from both clinical and environmental sources were tested for their susceptibility to commonly used contact lens multi-purpose cleaning solutions (MPS) and hydrogen peroxide cleaning solutions. These toxicity tests showed that different strains responded differently to the effects of the cleaning solutions. In all cases cysts were more resistant than trophic amoebae and no MPS was 100% effective at killing acanthamoebae, and, as would be expected, the hydrogen peroxide systems performed better than the MPS. However, reduced concentrations of hydrogen peroxide do not provide a kill rate comparable to what is currently available. Over a 2 year period, 228 water samples were obtained from the greater Chicago area and scored for the presence of protists including Acanthamoeba. Over 50% of domestic water samples tested positive for protists, with 20% being positive for Acanthamoeba. The genotypes found in both the water and clinical isolates were not unique, with most belonging to the T4 genotype (44 samples), and only 4 T3. Finally, the pathogenicity study was done to determine if grasshoppers could be used to evaluate the pathogenicity and/or virulence of Acanthamoeba. It was shown that grasshoppers do respond differently to clinical versus environmental strains, and are a promising possible animal model for use in the study of Acanthamoeba.
Paul Fuerst, PhD (Advisor)
David Denlinger, PhD (Committee Member)
Laura Kubato, PhD (Committee Member)
Thomas Mauger, MD (Committee Member)
166 p.
Microbiology
Acanthamoeba; model organism; pathogenicity; contact lens solution

Recommended Citations

Citations

  • Shoff, M. E. (2008). Analysis of the Susceptibility, Prevalence, and Pathogenicity of the Opportunistic Pathogen Acanthamoeba [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1229352913

    APA Style (7th edition)

  • Shoff, Megan. Analysis of the Susceptibility, Prevalence, and Pathogenicity of the Opportunistic Pathogen Acanthamoeba. 2008. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1229352913.

    MLA Style (8th edition)

  • Shoff, Megan. "Analysis of the Susceptibility, Prevalence, and Pathogenicity of the Opportunistic Pathogen Acanthamoeba." Doctoral dissertation, Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1229352913

    Chicago Manual of Style (17th edition)

osu1229352913
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© 2008, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.