RAPID SAMPLE PROCESSING AND FAST CHROMATOGRAPHY FOR IDENTIFICATION OF BACTERIA BY FATTY ACID ANALYSIS

Authors: Buyer, Jeffrey

Submitted to: Journal of Microbiological Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2002
Publication Date: 8/9/2002
Citation: BUYER, J.S. RAPID SAMPLE PROCESSING AND FAST CHROMATOGRAPHY FOR IDENTIFICATION OF BACTERIA BY FATTY ACID ANALYSIS. JOURNAL OF MICROBIOLOGICAL METHODS. S1:209-215. 2002.

Interpretive Summary: Many problems in microbiology require that bacteria be identified. For example, bacteria that suppress plant disease need to be thoroughly characterized before they can be released into the environment. Bacteria have to be identified in the clinical laboratory in order to treat disease. One of the most powerful and widely used methods for identification of bacteria is by gas chromatographic analysis of the fatty acids that are present in the lipids of bacterial membranes. The Microbial Identification System (Microbial ID, Inc., Newark, DE) is the only commercially available system for this purpose. While it works very well it is not very fast and analytical microbiologists have been searching for quicker methods of identification. We developed two modifications to the system that speed analysis three-fold while still allowing the preexisting databases of fatty acids and bacteria to be used. Sample processing is performed in microtubes using multichannel pipetters, while gas chromatography is performed with a smaller column with much shorter retention times than the standard column. This may be useful for rapid identification of large numbers of bacteria in a clinical or environmental laboratory.

Technical Abstract: A commercially available system for microbial identification by fatty acid analysis (Microbial Identification System, MIDI Inc., Newark, Delaware, USA) requires a four-step sample derivatization procedure in screw-cap test tubes. By using glass tubes in a 96-well format with multichannel pipetting the time required for sample preparation can be greatly reduced. The standard gas chromatography column is replaced with a smaller column, reducing the gas chromatography run time to one-third of the standard time. Either or both of these procedures can be easily implemented in any laboratory using the MIDI system, resulting in faster identifications and higher sample throughput.