AUTHOR=Ojasanya Rasaq A. , Gardner Ian A. , Groman David , Saksida Sonja , Saab Matthew E. , Thakur Krishna K. 

TITLE=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

JOURNAL=Frontiers in Veterinary Science

VOLUME=9

YEAR=2022

URL=https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2022.1031373

DOI=10.3389/fvets.2022.1031373

ISSN=2297-1769

ABSTRACT=<p>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 <italic>Yersinia ruckeri</italic> isolated from Atlantic salmon (<italic>Salmo salar</italic>). The novel MSP was prepared using an isolate of <italic>Y. ruckeri</italic> recovered from Atlantic salmon and confirmed by 16S rRNA gene sequencing. Subsequently, a validation set which comprises 29 isolates of <italic>Y. ruckeri</italic> were examined from three fishes: Atlantic salmon (<italic>Salmo salar</italic>) (<italic>n</italic> = 26), American eel (<italic>Anguilla rostrata</italic>) (<italic>n</italic> = 1), and Atlantic cod (<italic>Gadus morhua</italic>) (<italic>n</italic> = 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 <italic>Y. ruckeri</italic>, 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 (<italic>n</italic> = 3) of <italic>Y. ruckeri</italic> in the reference library and did not falsely identify any closely related bacteria to <italic>Y. ruckeri</italic>. This study reports the development of a novel MSP of high analytical sensitivity and specificity for rapid identification of <italic>Y. ruckeri</italic> using MALDI-TOF MS.</p>