Chapter 3
Use of MALDI-ToF Mass Spectrometry for Identification
of Leptospira
Dominique Girault, Malia Kainiu, Emilie Barsac, Roman Thibeaux,
and Cyrille Goarant
Abstract
Medical microbiology has used phenotypical and metabolic criteria to identify bacterial pathogens for
decades. However, no such criteria have been applied to identify leptospires at the species level. In the
recent years, matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry
(MS) has emerged as new tool for the identification of bacterial species in the medical microbiology
laboratory. This technology has rapidly gained more and more popularity. Actually, this technique is
sensitive and economic, saving both labor and bench costs, but also rapid, significantly reducing turnaround
time from isolation to identification. MALDI-ToF MS provides an unprecedented tool for the rapid
identification of Leptospira at the species level.
Key words Leptospira, Isolate, Identification, MALDI-ToF MS, Spectra database
1 Introduction
Bacteria in the genus Leptospira have long been classified into only
two species, namely, “L. interrogans sensu lato” for all pathogenic
strains and “L. biflexa sensu lato” for all saprophytic strains. The
ability to grow at 13
C and in the presence of the purine analogue
8-azaguanine were considered unique features of L. biflexa and were
used as metabolic criteria for identification [1, 2]. However, Leptospira taxonomy has been revolutionized since the advent of molecular approaches [3, 4] and the discovery of a new “intermediate”
cluster in the genus [5]. Additional novel species were recently
described, mostly from the environment, now bringing the total
number of species to 64 [6–8]. No phenotypical identification key is
available to identify such a large number of species. Therefore, DNA
sequencing is most frequently used to identify Leptospira isolates at
the species level. Here we summarize the steps to identify Leptospira
isolates at the species level using MALDI-ToF MS in the medical
microbiology laboratory [7, 9–11].
Nobuo Koizumi and Mathieu Picardeau (eds.), Leptospira spp.: Methods and Protocols, Methods in Molecular Biology, vol. 2134,
https://doi.org/10.1007/978-1-0716-0459-5_3, © Springer Science+Business Media, LLC, part of Springer Nature 2020
23
Use of MALDI-ToF Mass Spectrometry for Identification
of Leptospira
Dominique Girault, Malia Kainiu, Emilie Barsac, Roman Thibeaux,
and Cyrille Goarant
Abstract
Medical microbiology has used phenotypical and metabolic criteria to identify bacterial pathogens for
decades. However, no such criteria have been applied to identify leptospires at the species level. In the
recent years, matrix-assisted laser desorption/ionization time-of-flight (MALDI-ToF) mass spectrometry
(MS) has emerged as new tool for the identification of bacterial species in the medical microbiology
laboratory. This technology has rapidly gained more and more popularity. Actually, this technique is
sensitive and economic, saving both labor and bench costs, but also rapid, significantly reducing turnaround
time from isolation to identification. MALDI-ToF MS provides an unprecedented tool for the rapid
identification of Leptospira at the species level.
Key words Leptospira, Isolate, Identification, MALDI-ToF MS, Spectra database
1 Introduction
Bacteria in the genus Leptospira have long been classified into only
two species, namely, “L. interrogans sensu lato” for all pathogenic
strains and “L. biflexa sensu lato” for all saprophytic strains. The
ability to grow at 13
C and in the presence of the purine analogue
8-azaguanine were considered unique features of L. biflexa and were
used as metabolic criteria for identification [1, 2]. However, Leptospira taxonomy has been revolutionized since the advent of molecular approaches [3, 4] and the discovery of a new “intermediate”
cluster in the genus [5]. Additional novel species were recently
described, mostly from the environment, now bringing the total
number of species to 64 [6–8]. No phenotypical identification key is
available to identify such a large number of species. Therefore, DNA
sequencing is most frequently used to identify Leptospira isolates at
the species level. Here we summarize the steps to identify Leptospira
isolates at the species level using MALDI-ToF MS in the medical
microbiology laboratory [7, 9–11].
Nobuo Koizumi and Mathieu Picardeau (eds.), Leptospira spp.: Methods and Protocols, Methods in Molecular Biology, vol. 2134,
https://doi.org/10.1007/978-1-0716-0459-5_3, © Springer Science+Business Media, LLC, part of Springer Nature 2020
23