An improved PCR-based method for detection and differentiation of Entamoeba histolytica and Entamoeba dispar in formalin-fixed stools.
Detection of infectious agents in faecal samples by polymerase chain reaction (PCR) can be limited by the presence of substances which inhibit DNA amplification. Here, an improved protocol is reported for directly isolating DNA from fresh and aged formalin-fixed stools, after concentration by formalin-ethyl acetate (FEA). The protocol was successfully applied to detect DNA of Entamoeba histolytica/Entamoeba dispar complex in stools by nested PCR, showing high specificity and low detection limit. Extended time of specimen storage in formalin had no influence on PCR yields. This PCR-based method offers technical advantages for routine detection and discrimination of invasive E. histolytica and non-invasive E. dispar.
Paglia
Maria Grazia
MG
Laboratory of Clinical Pathology, National Institute for Infectious Diseases Lazzaro Spallanzani I.R.C.C.S., Via Portuense 292, 00149 Rome, Italy. pagliamicromol@inmi.it
Visca
Paolo
P
D000818:Animals; D004747:Entamoeba / Q000145:classification* / Q000302:isolation & purification*; D004748:Entamoeba histolytica / Q000302:isolation & purification; D004749:Entamoebiasis / Q000175:diagnosis; D005243:Feces / Q000469:parasitology*; D005404:Fixatives; D005557:Formaldehyde; D006801:Humans; D016133:Polymerase Chain Reaction / Q000379:methods*; D012680:Sensitivity and Specificity
D005404:Fixatives; D005557:Formaldehyde