Comparison of real-time PCR protocols for differential laboratory diagnosis of amebiasis.
Specific identification of Entamoeba spp. in clinical specimens is an important confirmatory diagnostic step in the management of patients who may be infected with Entamoeba histolytica, the species that causes clinical amebiasis. Distinct real-time PCR protocols have recently been published for identification of E. histolytica and differentiation from the morphologically identical nonpathogenic Entamoeba dispar. In this study, we compared three E. histolytica real-time PCR techniques published by December 2004. The limits of detection and efficiency of each real-time PCR assay were determined using DNA extracted from stool samples spiked with serially diluted cultured E. histolytica trophozoites. The ability of each assay to correctly distinguish E. histolytica from E. dispar was evaluated with DNA extracted from patients' stools and liver aspirates submitted for confirmatory diagnosis. Real-time PCR allowed quantitative analysis of the spiked stool samples, but major differences in detection limits and assay performance were observed among the evaluated tests. These results illustrate the usefulness of comparative evaluations of diagnostic assays.
Qvarnstrom
Yvonne
Y
National Center for Infectious Diseases, Centers for Disease Control and Prevention, Public Health Service, U.S. Department of Health and Human Services, Atlanta, Georgia 30341, USA.
James
Cleve
C
Xayavong
Maniphet
M
Holloway
Brian P
BP
Visvesvara
Govinda S
GS
Sriram
Rama
R
da Silva
Alexandre J
AJ
D000818:Animals; D017931:DNA Primers; D016054:DNA, Protozoan / Q000032:analysis*; D003937:Diagnosis, Differential; D004748:Entamoeba histolytica / Q000235:genetics / Q000302:isolation & purification*; D004749:Entamoebiasis / Q000175:diagnosis*; D005243:Feces / Q000469:parasitology; D006801:Humans; D008099:Liver / Q000469:parasitology; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
D017931:DNA Primers; D016054:DNA, Protozoan