Development of DNA-based assays for the detection of Trichomonas vaginalis

Identifier:  TDX:4528

Handle: https://hdl.handle.net/20.500.11797/TDX4528

Authors:  Castro Justo, Christine Aubrey

Abstract:
The parasite Trichomonas vaginalis is the causative agent of trichomoniasis – the longstanding world’s most common, non-viral, curable sexually transmitted infection (STI). Numerous assays are available for the detection of T. vaginalis but syndromic diagnosis prevails in low- and middle-income countries due to limited resources and access. There is a need to replace syndromic diagnosis with an etiological one, detecting the parasite in part or in whole. The development of alternative low-cost, rapid point-of-care tests (POCTs) for T. vaginalis has been identified as one of the global STI research priorities set by the World Health Organization. Moreover, this is a key step in the realization of the 2030 goal of 50% reduction of cases of trichomoniasis and the overall goal of eliminating STIs as a public health threat. This doctoral thesis presents the development of DNA-based assays that can be implemented in a DNA-based POCT for T. vaginalis. Two DNA-based lateral flow tests (LFAs) were developed from initial works using microplate-based assays. Both LFAs exploit the use of DNA oligonucleotides as biorecognition molecule and are devoid of the typical biotin/streptavidin system. The first assay utilizes a pair of DNA aptamers, selected against the adhesin protein 65, for the direct detection of the T. vaginalis. The second assay utilizes tailed primers for the isothermal amplification of T. vaginalis repeatitive DNA and detection by DNA hybridization to complementary oligonucleotides. Preliminary evaluation against clinical samples demonstrated potential of the developed assays as POCTs.