Laboratory Diagnosis of Amoebic Keratitis: Comparison of Four Diagnostic Methods for Different Types of Clinical Specimens
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Published:2009-05
Issue:5
Volume:47
Page:1314-1318
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ISSN:0095-1137
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Container-title:Journal of Clinical Microbiology
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language:en
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Short-container-title:J Clin Microbiol
Author:
Boggild Andrea K.1, Martin Donald S.2, Lee Theresa YuLing2, Yu Billy2, Low Donald E.234
Affiliation:
1. Tropical Diseases Unit, Toronto General Hospital, Toronto, Ontario, Canada M5G 2C4 2. Parasitology Laboratory, Ontario Agency for Health Protection and Promotion, Etobicoke, Ontario, Canada M9P 3T1 3. Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada 4. Department of Microbiology, Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5
Abstract
ABSTRACT
Amoebic keratitis causes significant ocular morbidity in contact lens wearers. Current diagnostic methods for amoebic keratitis are insensitive and labor-intensive and have poor turnaround time. We evaluated four laboratory methods for detection of acanthamoebae in clinical specimens. Deidentified, delinked consecutive specimens from patients with suspected amoebic keratitis were assayed for acanthamoebae by direct smear analysis, culture, and PCR using two different primer sets specific for
Acanthamoeba
ribosomal DNA. The consensus reference standard was considered fulfilled when the results for any two of the four tests were positive, and the outcome measures were sensitivity and specificity. Of 107 specimens assayed over an 18-month period, 20 were positive for acanthamoebae. The sensitivity and specificity of each assay were as follows, respectively: for smear analysis, 55% (95% confidence interval [CI], 33.2 to 76.8%) and 100%; for culture, 73.7% (95% CI, 54.4 to 93.0%) and 100%; for PCR using Nelson primers, 90% (95% CI, 76.9 to 100%) and 90.8% (95% CI, 84.7 to 96.9%); and for PCR using JDP primers, 65% (95% CI, 44.1 to 85.9%) and 100%. Nelson primer PCR demonstrated a single-organism level of analytic sensitivity. The performance characteristics of the assays varied by specimen type, with contact lenses and casings showing the highest rates of detectable acanthamoebae and the highest diagnostic sensitivities for direct smear analysis, culture, and JDP primer PCR, though these results are based on small numbers and should be interpreted cautiously. These findings have important implications for clinicians collecting diagnostic specimens and for diagnostic laboratories, especially in outbreak situations.
Publisher
American Society for Microbiology
Subject
Microbiology (medical)
Reference21 articles.
1. Banoo, S., D. Bell, P. Bossuyt, A. Herring, D. Mabey, F. Poole, P. G. Smith, N. Sriram, C. Wongsrichanalai, R. Linke, R. O'Brien, M. Perkins, J. Cunningham, P. Matsoso, C. M. Nathanson, P. Olliaro, R. W. Peeling, A. Ramsay, et al. 2007. Evaluation of diagnostic tests for infectious diseases: general principles. Nat. Rev. Microbiol.5(Suppl. 11):S17-S29. 2. Bryant, K., J. Bugante, T. Chang, S. Chen, J. Rosenberg, R. Hammond, K. McConnell, R. Sanderson, J. Elm, M. Nakata, C. Wakida, C. Austin, J. Bestudik, M. G. Bordson, C. Conover, L. Granzow, A. Pelletier, V. Rea, A. Chu, E. Luckman, K. Signs, J. Harper, T. Damrow, E. Mosher, K. Kruger, E. Saheli, M. Cassidy, J. Hatch, A. Weltman, E. J. Garcia Rivera, Y. Garcia, M. A. Kainer, J. Archer, C. Joslin, P. Cernoch, D. Jones, M. Hamill, A. Matoba, S. Pflugfelder, K. Wilhelmus, S. Beavers, T. Chen, K. Christian, M. Cooper, D. Dufficy, M. Gershman, M. Glenshaw, A. Hall, S. Holzbauer, A. Huang, A. Langer, Z. Moore, A. S. Patel, L. R. Carpenter, J. Schaffzin, J. Su, I. Trevino, T. Weiser, P. Wiersma, S. Lorick, and J. R. Verani. 2007. Acanthamoeba keratitis multiple states, 2005-2007. MMWR Morb. Mortal. Wkly. Rep.56:532-534. 3. Clarke, D. W., and J. Y. Niederkorn. 2006. The pathophysiology of Acanthamoeba keratitis. Trends Parasitol.22:175-180. 4. Gupta, N., and R. Tandon. 2008. Investigative modalities in infectious keratitis. Indian J. Ophthalmol.56:209-213. 5. Hammersmith, K. M. 2006. Diagnosis and management of Acanthamoeba keratitis. Curr. Opin. Ophthalmol.17:327-331.
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