VITEK MS Collaborative Study Outline - eBook

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Calibration Wells

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 Acquisition  

  Acquisition             Acquisition  

Group   5  6  The E. coli ATCC 8739 strain must be deposited on calibration well positions, depending on the number  7  of samples tested (1 calibrator per acquisition group of 16 spots). Follow the directions for Preparation  8  of Bacteria to prepare the E. coli ATCC 8739 calibration strain.  9  Using a 1 μl loop, pick up part of a suitable colony.  10  Make sure not to pick up any agar with the colony as this would have a negative impact on the  11  spectrum.  12  Some microorganisms, such as Streptococci, grow as very small colonies. In such cases, pick up several  13  similar colonies and deposit them on one spot.  14  NOTE: Do not deposit more than 1 (Single Deposit Mode) or 2 (Duplicate Deposit Mode) samples at a  15  time before adding matrix to the target spots.  16  Apply the sample to the center of the spot. Take special care not to apply too much organism. The  17  appropriate amount on a spot is shown in the picture below. If insufficient colony material was  18  deposited, take a new loop and introduce additional organism.  19  21  22  Smear a thin layer of the sample on the spot, then discard the used loop.  23  Open the microtube containing the VITEK MS‐CHCA matrix. Add precisely 1.0 μl of matrix to the center  24  of the spot. Discard the pipette tip. The matrix/microorganism suspension is then left to dry completely.  25  It is strongly recommended to deposit the matrix as indicated in the VITEK MS Prep Station workflow for  26  bacteria: 2 by 2 in duplicate mode or 1 by 1 in single mode.  27  Note: The VITEK MS‐CHCA matrix contains a high concentration of organic solvents; it is recommended  28  to close the tube after dispensing to avoid evaporation.  29      Group           Group  20     Too much     Too little          OK                OK 

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