ERP Micro December 2019

Note : The target carrier should only be moved to the OUT position when target plates are being exchanged. Measured target plates can remain in the instrument until the next target plate is ready to be processed. If no target is available, move the target carrier into the instrument (without a target plate in place) and move it out again only when the next target plate is ready to be loaded. Note : When exchanging target plates, do not leave the load port lid open for any longer than necessary. Leaving the load port lid open for extended periods does not damage the instrument but will prolong target loading by as much as 30 min. G. Operating the MALDI Biotyper System ( a ) Log on to the MALDI Biotyper System computer. ( b ) Start the MALDI Biotyper System software by first clicking on the Flex Control icon. Then click onto the RTC software icon on the desktop. ( c ) After successful startup, the main application window is displayed. ( d ) Prepare a test run according to the MALDI Biotyper System Instructions for Use. H. Results ( a ) MALDI Biotyper System identification consists of two steps, which are performed on each test and BTS control position. ( b ) A mass spectrum is acquired from the test or BTS control position (measurement step). ( c ) The resulting mass spectrum is processed, and the resulting peak pattern is matched against reference patterns in the MALDI Biotyper reference library (identification step). ( d ) The identification step is started immediately after the associated measurement step has been completed and a mass spectrum is available. ( e ) When the identification run is started, the sample positions to be measured appear as white circles in the target display. ( f ) During the run, the appearance of the sample positions and BTS control positions in the target display reflects the success of the measurement and identification process of each test organism. ( g ) If spectrum measurement is successfully completed, the left half of the sample position is colored green. If measurement fails, the left half of the sample position is colored orange. ( h ) The coloring of the right half of the sample position indicates the score value of the identification (green, yellow, or red). The legend display explains the color-coding used to indicate the status of sample positions in the target display. ( i ) The MBT subtyping module supports the identification of the most encountered Listeria species in food, feed, and related environmental samples: L. innocua , L. ivanovii , L. monocytogenes , L. seeligeri , and L. welshimeri . This module is not required for L. grayi identification. The subtyping module starts automatically and assesses the quality of the profiles before checking the specific biomarkers for species identification. The other genera and related species are identified using the Consistency Category of the MBT Compass Manual. Scores >2.0 will be presented in green and are determined to be acceptable with high confidence identification (both Listeria species and non- Listeria organisms). Results presented in yellow will have values between 1.70 and 1.99 and are determined to be acceptable with low confidence identification (both Listeria species and non- Listeria organisms). Results presented in red are considered not acceptable for identification. The consistency category of the identification is

F. Direct Transfer (DT) ( a )  Samples preparation procedure .—( 1 ) Using a sterile colony-transfer device, smear an isolated colony of bacteria or yeast as a thin film directly onto a single sample position on a cleaned reusable target or disposable biotarget ( see Figure 2017.10 ). Note : After incubation of bacteria on recommended isolation media for 24–48 h at the reference method-specified temperatures following the appropriate reference methods, colonies are stable for up to 12 h when held at room temperature (20–25°C). If testing is not done within 12 h, subculture the test organism before testing on the MALDI Biotyper System. ( 2 ) Select a minimum of one BTS control position on a target to inoculate with BTS solution. It is mandatory to get at least one valid BTS control per target and per run. Therefore, it is advised to select two BTS control positions. ( 3 ) Pipet 1 μL of reconstituted BTS solution onto the two selected positions and dry at room temperature (20–25°C). Note : After samples and BTS have dried, HCCA Matrix solution must be added within 30 min, or the target must be cleaned and the inoculation of samples BTS must be repeated. ( 4 ) Overlay each sample position and BTS control positions with 1 μL HCCAMatrix solution. Use a new pipet tip to add HCCA Matrix to each inoculated sample position. Note : Make sure that the screw-cap tube containing HCCAMatrix is tightly closed after use to minimize solvent evaporation. ( 5 ) Dry the inoculated target at room temperature (20–25°C). ( 6 ) The inoculated target is now ready for use. Note : An inoculated target must be processed within 24 h of preparation or the target must be cleaned and the inoculation of samples and BTS must be performed again. (b)  Loading and ejecting target.— ( 1 ) Make sure that the target plate carrier is in the OUT position. ( 2 ) Open the load port lid and place the target plate onto the target platform. Note : If the lid does not open easily, the target carrier may be in the IN position. If this is the case, move the target carrier to the OUT position by pressing the MALDI target plate IN/ OUT button once. ( 3 ) Once the target plate has been loaded, close the lid. ( 4 ) Press the MALDI target plate IN/OUT button once. The MALDI target plate loading procedure starts and the green READY andACCESS LEDs go off. The green READYLED will be lit again when the loading procedure has been successfully completed. The MALDI target plate loading procedure typically takes 2 to 3 min. If the instrument is not ready after 5 min: ( a ) Press the MALDI target plate IN/OUT button once to eject the target plate. ( b ) When the green ACCESS LED is turned on, open and close the load port lid. ( c ) Press the MALDI target plate IN/OUT button once to reload the target plate. Note : The green READY LED will be off and the yellow WARM-UP LED will be lit if the laser is in standby mode. The laser will enter this mode after 10 min with no acquisition. The green READY LED will be lit again when a new acquisition sequence is started. (c) To eject a target plate.— ( 1 ) Press the MALDI target plate IN/OUT button once. The MALDI target plate ejection procedure starts and the green READY and ACCESS LEDs are off. ( 2 ) When the green ACCESS LED is lit again, open the load port lid, remove the target, and close the load port lid.

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