Numerical analysis of electrophoretic protein patterns of Providencia stuartii strains from urine, wound and other clinical sources

Eighty-six strains of Providencia stuartii (mainly of human origin) were characterized by one-dimensional SDS-PAGE of cellular proteins. The strains came from various countries; 52 were from urine, 11 from wounds, five from blood (one of these also from urine), four from ear infections, two each from faeces and sputum, one from ‘alimentation’and nine from unknown sources. The protein patterns, which contained 45 to 50 discrete bands, were highly reproducible. The patterns of 46 Prov, stuartii strains (selected to represent the full range of protein pattern diversity) plus those of the type strains of the four other Providencia species were used as the basis for two numerical analyses. In the first, which included all the protein bands, the Prov. stuartii strains formed 13 clusters at the 88% S level. In the second analysis, in which the principal protein bands (in the 33.8–40.7 kDa range) were excluded, 45 of the 46 Prov. stuartii strains formed a single cluster at the 82% S level, whilst the four Providencia reference strains remained unclustered. The 40 strains of Prov. stuartii not included in the cluster analysis were assigned to a protein type by calculating their similarity with the strains in the database used for the cluster analysis. We conclude that high resolution PAGE combined with computerized analysis of protein patterns provides the basis for typing clinical strains of Prov. stuartii. Reference strains of each of the 13 PAGE types identified are available from NCTC for inclusion in future studies.