Biodiversity of Environmental Leptospira: Improving Identification and Revisiting the Diagnosis

Abstract

Leptospirosis is an important environmental disease and a major threat to human health causing at least 1 million clinical infections annually. There has recently been a growing interest in understanding the environmental lifestyle of <i>Leptospira</i>. However, <i>Leptospira</i> isolation from complex environmental samples is difficult and time-consuming and few tools are available to identify <i>Leptospira</i> isolates at the species level. Here, we propose a polyphasic isolation and identification scheme, which might prove useful to recover and identify environmental isolates and select those to be submitted to whole-genome sequencing. Using this approach, we recently described 12 novel <i>Leptospira</i> species for which we propose names. We also show that MALDI-ToF MS allows rapid and reliable identification and provide an extensive database of <i>Leptospira</i> MALDI-ToF mass spectra, which will be valuable to researchers in the leptospirosis community for species identification. Lastly, we also re-evaluate some of the current techniques for the molecular diagnosis of leptospirosis taking into account the extensive and recently revealed biodiversity of <i>Leptospira</i> in the environment. In conclusion, we describe our method for isolating <i>Leptospira</i> from the environment, confirm the usefulness of mass spectrometry for species identification and propose names for 12 novel species. This also offers the opportunity to refine current molecular diagnostic tools.