Development and validation of main spectral profile for rapid identification of Yersinia ruckeri isolated from Atlantic salmon using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

• Published in: Frontiers in Veterinary Science
• Main Authors: Ojasanya, Rasaq A., Gardner, Ian A., Groman, David, Saksida, Sonja, Saab, Matthew E., Thakur, Krishna K.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Frontiers Media SA 2022
• Subjects: atlantic cod; Atlantic salmon; Gadus morhua; Salmo salar
• Online Access: http://dx.doi.org/10.3389/fvets.2022.1031373; https://www.frontiersin.org/articles/10.3389/fvets.2022.1031373/full

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows rapid and reliable identification of microorganisms. The accuracy of bacterial identification using MALDI-TOF MS depends on main spectral profiles (MSPs) provided in a quality-assured commercial reference library, which requires ongoing improvement. This study aimed to develop and validate an in-house MALDI-TOF MS MSP to rapidly identify Yersinia ruckeri isolated from Atlantic salmon ( Salmo salar ). The novel MSP was prepared using an isolate of Y. ruckeri recovered from Atlantic salmon and confirmed by 16S rRNA gene sequencing. Subsequently, a validation set which comprises 29 isolates of Y. ruckeri were examined from three fishes: Atlantic salmon ( Salmo salar ) ( n = 26), American eel ( Anguilla rostrata ) ( n = 1), and Atlantic cod ( Gadus morhua ) ( n = 2). These isolates were randomly selected from the Atlantic Veterinary College, Aquatic Diagnostic Services Bacteriology Laboratory's culture collection to validate the novel MSP. Analytical sensitivity of MALDI-TOF MS using the novel MSP to identify the validation set was 86.2%. Repeatability was assessed by acquiring spectra from 30 different spots of a randomly-selected isolate of Y. ruckeri , and analyzed spectra from each spot were compared against the novel MSP. The coefficient of variation was 3.3%. The novel MSP clustered with Bruker MSPs ( n = 3) of Y. ruckeri in the reference library and did not falsely identify any closely related bacteria to Y. ruckeri . This study reports the development of a novel MSP of high analytical sensitivity and specificity for rapid identification of Y. ruckeri using MALDI-TOF MS.