Evaluation of small-subunit rRNA touchdown polymerase chain reaction for direct detection of Entamoeba histolytica in human pus samples from patients with amoebic liver abscess.

PURPOSE: The aim of the present study was to evaluate the use of touchdown polymerase chain reaction (TD-PCR) for the detection of Entamoeba histolytica in liver pus samples obtained from patients with a clinical diagnosis of amoebic liver abscess (ALA) using small-subunit rRNA (SSU rRNA) as the target gene.

MATERIALS AND METHODS: Microscopic examination in vitro culture and serological test for the detection of E. histolytica in 67 pus samples obtained from ALA patients was performed. Molecular studies were carried out by both conventional PCR and TD-PCR targeting the SSU rRNA gene using the same sets of primers and the results were compared.

RESULTS: TD-PCR detected the presence of E. histolytica in 86.5% of the liver pus samples within 2.5 h as compared with 82.08% by conventional PCR within 3.5-4 h.

CONCLUSION: TD-PCR assay may serve as a relatively better detection method for E. histolytica over conventional PCR with respect to the turnaround time, increased sensitivity, specificity and yield.