RT Journal Article
SR Electronic
T1 Improving the specific diagnosis of trematode, cestode and nematode infections by a multiplex single-tube real-time PCR assay
JF Journal of Clinical Pathology
JO J Clin Pathol
FD BMJ Publishing Group Ltd and Association of Clinical Pathologists
SP 487
OP 492
DO 10.1136/jclinpath-2018-205590
VO 72
IS 7
A1 Samson S Y Wong
A1 Rosana W S Poon
A1 Kelvin K W To
A1 Jasper F W Chan
A1 Gang Lu
A1 Fanfan Xing
A1 Vincent C C Cheng
A1 Kwok-Yung Yuen
YR 2019
UL http://jcp.bmj.com/content/72/7/487.abstract
AB Aims Helminth infections are becoming uncommon in high-income countries and laboratory staff may lose expertise in their morphological identification, especially in histological sections where speciation of helminths is challenging. Commercially available molecular diagnostic panels for faecal specimens only offer tests for protozoa but not helminths. We aim to improve the identification accuracy of helminths using a multiplex PCR assay.Methods We designed three pairs of PCR primers and probes targeting multicopy genes for a multiplex single-tube real-time PCR assay which covers 16 trematode (28S rRNA gene), 24 cestode (cox1 gene) and 33 nematode (cox1 gene) species. Helminths (n=27) from faecal samples (n=10), fresh parasites (n=11), formalin-fixed specimens (n=4), cerebrospinal fluid (n=1) and bile (n=1) were examined morphologically and tested by PCR. Fifty stool samples negative for parasites by microscopy were also tested.Results The PCR assay correctly identified the genera of all tested helminths. Agarose gel electrophoresis and sequencing of the purified PCR amplicons confirmed that the PCR products were of correct sizes with 100% correlation with the respective species. Sequencing of the cox1 gene failed to identify Capillaria spp. in one sample owing to the lack of corresponding sequences in GenBank. PCR and sequencing of the nematode 18S rRNA gene using consensus primers showed 100% homology with Capillaria spp. sequence. No positive PCR products were found in the negative stool samples.Conclusions The highly specific test correctly identified all helminths in our cohort. It is a useful adjunct to helminth identification in difficult situations such as histological sections.