Comparison of a PCR-Based Method with Culture and Direct Examination for Diagnosis of Acanthamoeba keratitis

Autor: S Farnia, C M. Martín-Navarro, Z Babaei, F Rahimi, S Rezaie, M Mohebali, J Lorenzo-Morales, M Niyyati, B Valladares
Jazyk: angličtina
Rok vydání: 2009
Předmět:
Zdroj: Iranian Journal of Parasitology, Vol 4, Iss 2, Pp 38-43 (2009)
Druh dokumentu: article
ISSN: 1735-7020
2008-238X
Popis: "nBackground: The aim was to compare three different methods (direct examination, culture and PCR meth­ods) for the diagnosis of Acanthamoeba keratitis (AK) in corneal scrapes."nMethods: Twenty eight corneal scrapes and contact lenses were collected from keratitis patients and re­ferred to the De­partment of Medical Parasitology and Mycology, School of Public Health, Tehran Univer­sity of Medical Sci­ences. Corneal scrapes were divided in three parts for direct examination, culture on non-nutrient agar and PCR analysis. PCR analysis was also performed using a 18S rRNA gene primer pair (DF3 region). DF3 (Diagnostic frag­ment 3) is a region of the nuclear small subunit ribosomal RNA gene which is specific for detecting Acan­thamoeba strains."nResults: Acanthamoeba was the causative agent of keratitis in 50% of the patients. Direct smear of all pre­pared corneal scrapes in AK patients was negative and culture was positive in only 14.3% of the isolates. PCR analysis was positive in 71.4% of AK patients. These three methods were negative in corneal scrapes of non-AK patients. The sensitivity and specificity of PCR technique for the detection of Acanthamoeba sp. were calculated as 71.4% and 100%, respectively."nConclusion: According to high sensitivity and specificity of PCR-based method, this study confirmed that PCR using 18S rRNA gene primers (DF3 region) is more useful for detecting AK cases compare to culture and direct microscopy methods.
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