ABSTRACT
Human leishmaniases are widespread diseases with different clinical forms caused by about 20 species within the
Leishmania
genus.
Leishmania
species identification is relevant for therapeutic management and prognosis, especially for cutaneous and mucocutaneous forms. Several methods are available to identify
Leishmania
species from culture, but they have not been standardized for the majority of the currently described species, with the exception of multilocus enzyme electrophoresis. Moreover, these techniques are expensive, time-consuming, and not available in all laboratories. Within the last decade, mass spectrometry (MS) has been adapted for the identification of microorganisms, including
Leishmania
. However, no commercial reference mass-spectral database is available. In this study, a reference mass-spectral library (MSL) for
Leishmania
isolates, accessible through a free Web-based application (mass-spectral identification [MSI]), was constructed and tested. It includes mass-spectral data for 33 different
Leishmania
species, including species that infect humans, animals, and phlebotomine vectors. Four laboratories on two continents evaluated the performance of MSI using 268 samples, 231 of which were
Leishmania
strains. All
Leishmania
strains, but one, were correctly identified at least to the complex level. A risk of species misidentification within the
Leishmania donovani
,
L. guyanensis
, and
L. braziliensis
complexes was observed, as previously reported for other techniques. The tested application was reliable, with identification results being comparable to those obtained with reference methods but with a more favorable cost-efficiency ratio. This free online identification system relies on a scalable database and can be implemented directly in users' computers.
Identification of Leishmania by Matrix-Assisted Laser Desorption Ionization–Time of Flight (MALDI-TOF) Mass Spectrometry Using a Free Web-Based Application and a Dedicated Mass-Spectral Library