Rapid Identification of Vibrio Species of the Harveyi Clade Using MALDI-TOF MS Profiling With Main Spectral Profile Database Implemented With an In-House Database: Luvibase

Abstract

Vibrio bacteria, and particularly members of the Harveyi clade, are the causative agents of vibriosis. This disease is responsible for mass mortality events and important economic losses on aquaculture farms. Improvements in surveillance and diagnosis are needed to successfully manage vibriosis outbreaks. 16S rRNA gene sequencing is generally considered to be the gold standard for bacterial identification but the cost and long processing time make it difficult to apply for routine identification. In contrast, MALDI-TOF MS offers rapid diagnosis and is commonly used in veterinary laboratories today. The major limiting factor for using this technique is the low environmental bacterial diversity in the commonly available databases. Here, we demonstrate that the sole use of the commercially available Bruker BioTyper database is not fully adequate for identifying Vibrio bacteria isolated from aquaculture farms. We therefore developed a new in-house database named Luvibase, composed of 23 reference MALDI-TOF mass spectra profiles obtained from Vibrio collection strains, mostly belonging to the Harveyi clade. The comparison of the accuracy of MALDI-TOF MS profiling and 16S rRNA gene sequencing revealed a lack of resolution for 16S rRNA gene sequencing. In contrast, MALDI-TOF MS profiling proved to be a more reliable tool for resolving species-level variations within the Harveyi clade. Finally, combining the Luvibase with the Bruker ver.9.0.0.0 database, led to successful identification of 47 Vibrio isolates obtained from moribund abalone, seabass and oysters. Thus, the use of Luvibase allow for increased confidence in identifying Vibrio species belonging to the Harveyi clade.

Abundance and spatial patterns over time of Vibrionaceae and Vibrio harveyi in water and biofilm from a seabass aquaculture facility

“…Then, a single colony 188 was plated on MA (Difco Laboratories) and incubated 24 h, at 37 °C to ensure the purity of the 189 isolate. Preparation of bacterial extracts, target-loading and acquisition of MALDI-TOF MS 190 profiles were performed as previously described in Mougin et al (2020b). Briefly, the cellular 191 proteins of each bacterial isolate were extracted from bacterial cells according to manufacturer's 192 recommendations (Bruker France, Wissembourg, France).…”

“…The dynamics of cultivable Vibrionaceae was 86 assessed by culturing them on selective media at 37°C. Presumptive cultivable Vibrionaceae were 87 then identified using matrix-assisted laser desorption/ionization-time of flight mass spectrometry 88 (MALDI-TOF MS) using an in-house database, called Luvibase, previously and specifically 89 designed to identify Vibrio species from the Harveyi clade (Mougin et al, 2020b). The 90 abundance of V. harveyi was estimated using a mreb-targeted real-time PCR (Mougin et al, 91 2020a).…”

PVBase: A MALDI-TOF MS Database for Fast Identification and Characterization of Potentially Pathogenic Vibrio Species From Multiple Regions of China

“…that greatly supplemented the Bruker MBT Library with potentially pathogenic Vibrio species. Increasing the number of strains in the database improved the accuracy of identification, and increasing the number of Vibrio species expanded the scope of identification ( Mougin et al, 2020 ). We took V. parahaemolyticus , V. cholerae , V. alginolyticus , V. harveyi , and V. vulnificus , each of which have a large number of strains, as examples with which to explore the impact of increasing the number of strains in the database.…”

Vibrio aestuarianus subsp. cardii subsp. nov., pathogenic to the edible cockles Cerastoderma edule in France, and establishment of Vibrio aestuarianus subsp. aestuarianus subsp. nov. and Vibrio aestuarianus subsp. francensis subsp. nov.

“…The three representative strains for the three subspecies were further studied by whole-cell MALDI-TOF MS profiling. MALDI-TOF mass spectrum measurements and processing were carried out as described by Mougin et al [36]. The analyses were performed using Flex Analysis (version 3.4) and ClinProTool (version 3.0) software (Bruker Daltonics).…”

“…MALDI-TOF mass spectrum measurements and processing were carried out as described by Mougin et al . [ 36 ]. The analyses were performed using Flex Analysis (version 3.4) and ClinProTool (version 3.0) software (Bruker Daltonics).…”