Numerical analysis of electrophoretic protein patterns of Streptobacillus moniliformis strains from human, murine and avian infections.

A total of 31 cultures representing 22 different strains of Streptobacillus moniliformis has been characterised by unidimensional SDS-PAGE of cell proteins. The isolates were from sporadic and outbreak cases of human infection in the USA, UK and France, as well as mouse, turkey and rat isolates from various countries. The protein patterns, which contained 40-50 discrete bands, were highly reproducible and were used as the basis for a numerical analysis. Three clusters were obtained at the 86% similarity (S) level and these were further divided to give a total of seven clusters at the 90% S level. S. moniliformis strains, irrespective of the original host or geographical location of isolation, had a characteristic protein profile that enabled them to be easily distinguished from allied unclassifiable organisms. The analysis showed that Haverhill fever strains can be clearly distinguished from rat-bite fever strains. Protein-band differences amongst the latter strains corresponded with different geographical locations. We conclude that high resolution PAGE combined with computerised analysis of protein profiles provides the basis for typing clinical isolates of S. moniliformis. Seven PAGE types were identified and reference strains for each have been designated as a basis for future studies.