Numerical analysis of electrophoretic protein patterns of Providencia rettgeri strains from human faeces, urine and other specimens.

Thirty-one strains of Providencia rettgeri (mainly from humans) were characterized by one-dimensional SDS-PAGE of cellular proteins. The strains came from various countries and comprised 14 from urine, eight from faeces, two from bile (plus one from the liver of a sheep), two from sputum, one from an insect pupa and three the sources of which were unknown. Also included, for reference purposes, were the type strains of the four other Providencia species. The protein patterns, which contained 45-50 discrete bands, were highly reproducible and were used as the basis for two numerical analyses. In the first, which included all the protein bands, the 31 Prov. rettgeri strains formed 13 clusters at the 84% S level. In the second analysis, in which the principal protein bands (in the 33.3-41.3 kD range) were excluded, 29 of the 31 Prov. rettgeri strains formed a single cluster at the 81% S level, whilst the four Providencia reference strains remained unclustered. We conclude that high resolution PAGE combined with computerized analysis of protein patterns provides the basis for typing clinical strains of Prov. rettgeri. Reference strains of each of the 13 PAGE types identified are available from NCTC for inclusion in future studies.