Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry as a useful tool for the rapid identification of wild flea vectors preserved in alcohol

Abstract

Flea identification is a significant issue because some species are considered as important vectors of several human pathogens that have emerged or re-emerged recently, such as Bartonella henselae (Rhizobiales: Bartonellaceae) and Rickettsia felis (Rickettsiales: Rickettsiaceae). Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been evaluated in recent years for the identification of multicellular organisms, including arthropods. A preliminary study corroborated the usefulness of this technique for the rapid identification of fleas, creating a preliminary database containing the spectra of five species of flea. However, longterm flea preservation in ethanol did not appear to be an adequate method of storage in the context of specimen identification by MALDI-TOF MS profiling. The goal of the present work was to assess the performance of MALDI-TOF MS in the identification of seven flea species [Ctenocephalides felis (Siphonaptera: Pulicidae), Ctenocephalides canis, Pulex irritans (Siphonaptera: Pulicidae), Archaeopsylla erinacei (Siphonaptera: Pulicidae), Leptopsylla taschenbergi (Siphonaptera: Ceratophyllidae), Stenoponia tripectinata (Siphonaptera: Stenoponiidae) and Nosopsyllus fasciatus (Siphonaptera: Ceratophyllidae)] collected in the field and stored in ethanol for different periods of time. The results confirmed that MALDI-TOF MS can be used for the identification of wild fleas stored in ethanol. Furthermore, this technique was able to discriminate not only different flea genera, but also the two congeneric species C. felis and C. canis.

MALDI-TOF MS: optimization for future uses in entomological surveillance and identification of mosquitoes from New Caledonia

“…These observations are certainly related to the decrease of protein solubility which could lead to the qualitative and quantitative loss in spectra profiles, as others have shown [33]. To circumvent these limitations, some authors have suggested the query of specimens against MS reference spectra of specimens similarly preserved in ethanol for the same duration [25,34,35]. In supplementary experiments, LSVs improvement of specimens preserved in 70% ethanol was observed, when they were compared with MSP created from mosquitoes preserved under similar conditions for one day (Additional file 4: Figure S4a).…”

MALDI-TOF mass spectrometry for the identification of freshwater snails from Senegal, including intermediate hosts of schistosomes

“…forskalii were higher than those of specimens of the same species stored in ethanol ( S3 Table ). This difference may be due to the effect of ethanol on the quality of the MS spectra as previously reported in ethanol-stored lice, ticks, fleas and cercariae [ 25 , 40 , 53 , 67 , 77 , 88 ].…”

“…The quality of MS spectra is impacted by several parameters such as the storage conditions, the adjustment of the extraction solution volume used for protein extraction, the grinding method, and the selected body part [ 38 ]. In the first step of our study, we tested two kinds of disrupters: both tungsten beads and glass beads have proven to be useful and effective grinding methods in previous MALDI-TOF MS studies [ 38 , 40 , 66 , 67 ]. However, glass beads were reportedly the most commonly used disrupter, as they have been used for various arthropods identification [ 39 , 40 , 66 ], for mycobacteria identification, to disrupt the mycobacterial cell wall [ 68 , 69 ], and for fungal identification, as they were most efficient than steel beads for fungal proteins extraction [ 70 ].…”

Development of MALDI-TOF mass spectrometry for the identification of lice isolated from farm animals

“…It has been shown that MALDI-TOF MS is reliable for identifying arthropods preserved in alcohol, such as ticks [5], mosquitoes [29], and fleas [10]. Therefore, it would be interesting in the future to set up a MALDI-TOF MS protocol for identifying lice kept in alcohol [52]. It would also be interesting to assess whether MALDI-TOF MS can be used to differentiate lice which are infected or not infected by louse-borne microorganisms.…”