Identification and Typing of Bacteria by Protein Electrophoresis

Abstract

Polyacrylamide gel electrophoresis (PAGE) of bacterial whole-cell proteins yields complex banding patterns, which can be considered as highly specific fingerprints of the strains investigated. These protein electrophoregrams are highly reproducible, provided that standardised techniques are used and that strains are cultivated in similar conditions. Onedimensional (1D) protein electrophoresis proved to be a powerful, relatively simple and inexpensive method, which has been used for over 20 years for classification, identification and typing of diverse bacterial taxa (for reviews see: Garber and Rippon, 1968; Kersters and De Ley, 1980; Jackman, 1985, 1987; Kersters, 1985; Costas, 1992; Vauterin et al., 1993; Pot et al, 1994). The complex banding patterns can be quantified and compared by computer-assisted techniques. Databases for automated identification of bacterial strains can be constructed. One of the most popular electrophoretic techniques used is 1Delectrophoresis of whole-cell proteins (or cell-envelope proteins) in the presence of the denaturing anionic detergent sodium dodecylsulphate (SDS) (Laemmli, 1970). The protein electrophoretic technique is only applicable to strains which can be isolated as viable cultures; non-culturable or dormant microbial cells can thus not be analysed by the SDSPAGE method.