NUMERICAL-ANALYSIS OF SDS-PAGE PROTEIN-PATTERNS OF SERRATIA-MARCESCENS - A COMPARISON WITH OTHER TYPING METHODS

Twenty-five cultures comprising 18 clinical isolates of Serratia marcescens from two hospitals, the type strain of S. marcescens, two reference strains of S. marinorubra, the type or a reference strain of three other Serratia species and a reference strain of undetermined species, were characterized by one-dimensional sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) of whole-cell proteins. The protein patterns were highly reproducible and were used as the basis of a numerical analysis which divided the clinical isolates into eight protein types. Comparison with O-serotyping indicated that the level of discrimination by SDS–PAGE was similar. As with O-serotyping, a secondary scheme, such as phage typing, is necessary to differentiate strains of the same protein type. We conclude that high-resolution SDS–PAGE of proteins provides an effective adjunct to other methods for typing isolates of S. marcescens. © 1990, Cambridge University Press. All rights reserved.