AccuPRO-ID® Bacterical Identification Using MALDI-TOF Technology

Charles River AccuPRO-ID®, the first practical proteotypic identification method, utilizes matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. For industries that are required to identify microorganisms on a regular basis, the ideal technology is one that is accurate, reproducible, fast, and inexpensive. MALDI-TOF technology is less dependent on growth conditions than phenotypic methods because it analyzes primarily ribosomal proteins, which are not differentially expressed. The Charles River Accugenix® group optimized MALDI-TOF for use in bacterial identification and backs the method with 16S sequencing technology, providing clients with results 98% of the time – an increase of 26% over the commercially available BioTyper. Charles River conducted two different studies to evaluate MALDI-TOF as a suitable identification method and to compare it to commerciallyavailable methods of identification. Study 1: Evaluation of MALDI-TOF as a Method for Bacterial Identification The first study used a diversity panel of 31 known bacterial strains from culture collections and 146 different strains representing the 43 most frequently identified species that are known to occur in pharmaceutical manufacturing environments. Identities of all organisms and strains were verified using the using the AccuGENX-ID® 16S sequencing method. Results demonstrated that MALDI-TOF resulted in accurate species-level identifications most of the time, with a very low rate of species being misidentified. Bacteria used in each experiment were tested using both the direct spotting method and extract method (ethanol-formic acid-TFA) per the manufacturer’s recommendations. The following variables were tested: