Spectral database of Streptococcus pneumoniae, S. mitis and S. pseudopneumoniae (MALDI-TOF Mass Spectrometry)

A total of 80 strains, including 60 <strong>pneumococca</strong>l strains, 8 <strong><em>S. pseudopneumoniae</em> </strong>strains, and 12 <strong><em>S. mitis</em></strong> strains, were molecularly characterized and obtained from the National Reference Center for Pneumococci for the creation of the database. Each strain was tested a minimum of 20 and a maximum of 24 times using MALDI-TOF MS. <br> MALDI-TOF MS acquisition and analysis. Mass spectra were acquired using a Microflex LT instrument (Bruker Daltonics). The standard parameters of the CE-IVD method recommended by the manufacturer were used. This instrument was equipped with an N2 laser (377 nm) using the following parameters: mass range, 2,000 to 20,000 Da; ion source 1, 20 kV; ion source 2, 18.15 kV; lens, 6 kV; pulsed ion extraction, 150 ns; laser frequency, 20 Hz. A manual external calibration standard (Bacterial Test Standard; Bruker Daltonics) was used for calibration. Data acquisition was performed using FlexControl (version 3.0; Bruker Daltonics). <strong>Eight deposits were performed for each isolate.</strong> The dried spots were coated with 1 µl of α-cyano-4-hydroxycinnamic acid (a-HCCA) in 50% acetonitrile-2.5% trifluoroacetic acid and <strong>each spot was analysed three times by MALDI-TOF MS</strong>. <strong>A total of 1890 spectra were produced :</strong> <em>S. mitis</em> (n=264), <em>S.pneumoniae</em> (n= 1434), <em>S. pseudopneumoniae </em>(n=192) <strong>Fore more details:</strong> please contact [e-mail]