Protein Fingerprinting of Staphylococcus aureus by Capillary Electrophoresis with On-Capillary Derivatization and Laser-Induced Fluorescence Detection

This chapter describes a complete procedure for obtaining protein fingerprints of microorganisms using capillary electrophoresis (CE) with laser-induced fluorescence detection (LIF). Staphylococcus aureus , a human pathogen responsible of frequent and resistant infections, is used as model microorganism to show the feasibility of this procedure. Bacteria are grown in different culture media or submitted to temperature or nitrosative stress conditions. After the growth of the bacteria, the protein extracts are obtained by cell lysis using sonication. The water-soluble fraction of these lysates is derivatized on-capillary with the fluorogenic reagent 3-(2-furoyl)quinoline-2-carboxaldehyde. The fluorescent products are analyzed by CE and detected by LIF. Practical advices for the interpretation of the electropherograms are given. To do so, the variations of the protein fingerprints of the bacteria with the culture conditions, such as growth medium, or the stressing conditions, such as heat shock or nitrosative stress, are used as example.