Parasites & Vectors (Apr 2018)

Evaluation of fluorimetry and direct visualization to interpret results of a loop-mediated isothermal amplification kit to detect Leishmania DNA

  • Ana V. Ibarra-Meneses,
  • Israel Cruz,
  • Carmen Chicharro,
  • Carmen Sánchez,
  • Sylvain Biéler,
  • Tobias Broger,
  • Javier Moreno,
  • Eugenia Carrillo

DOI
https://doi.org/10.1186/s13071-018-2836-2
Journal volume & issue
Vol. 11, no. 1
pp. 1 – 9

Abstract

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Abstract Background Nucleic acid amplification tests (NAATs) have proven to be advantageous in the diagnosis of leishmaniases, allowing sensitive diagnosis of: (i) cutaneous leishmaniasis in long duration lesions and (ii) visceral leishmaniasis using a less-invasive sample like peripheral blood, in opposition to tissue aspiration required for parasite demonstration by microscopy. Despite their benefits, the implementation of NAATs for leishmaniasis diagnosis at the point-of-care has not been achieved yet, mostly due to the complexity and logistical issues associated with PCR-based methods. Methods In this work, we have evaluated the performance of a ready-to-use loop-mediated isothermal amplification (LAMP) kit using two real time fluorimeters to amplify leishmanial DNA obtained by silica column-based and Boil & Spin protocols. Results The different approaches used to run and interpret the LAMP reactions showed a performance equivalent to PCR and real-time PCR, using spiked and clinical samples. The time to positivity obtained with real-time fluorimetry showed an excellent correlation with both Ct values and parasite load from real-time quantitative PCR. Conclusions The results obtained open the possibility of using a highly stable, ready-to-use LAMP kit for the accurate diagnosis of leishmaniasis at the point-of-care. Furthermore, the feasibility of relating time to positivity, determined with a portable real-time fluorimeter, with the parasite burden could have a wider application in the management of leishmaniasis, such as in treatment efficacy monitoring or as a pharmacodynamics tool in clinical trials.

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