Starting from a 105 organisms/mL suspension, MALDI-TOF-MS yielded an unique protein profile for each one of 19 Leptospira species reference isolates with a 100%reproducibility over 12 repeats, allowing to create a Leptopsira database. MALDI-TOF-MS further accurately identified 20/21 additional reference isolates representative of various serogroups at the species level as Leptospira interrogans (n = 12), Leptospira kirschneri (n = 5), Leptospira borgpetersenii (n = 3), Leptospira noguchii (n = 1) with identification score value of 2-2.5. Furthermore, six clinical isolates previously identified by rpoB sequencing, were correctly identified by MALDI-TOF-MS as L. interrogans (n = 5) and L. borgpetersenii (n = 1) with identification score value of 2-2.6. Identification was achieved in 40 min starting from the Leptospira suspension.
MALDI-TOF-MS could complement serological and sequencing-based methods for the first line, rapid identification of Leptospira isolates in the clinical microbiology laboratory.