A method to differentiate between virulent and benign isolates of Bacteroides nodosus based on the thermal stability of their extracellular proteinases

Abstract

A rapid modification of the hide powder azure proteinase degrading test was devised to distinguish between benign and virulent strains of Bacteroides nodosus grown as cultures on either liquid or solid media. The assay was based on the difference in stability, at 60°C, of the enzymes released in the growth medium. The assay can be completed in four hours. Results for ovine virulent strains and their culture variants were similar and were clearly distinguishable from those of the ovine benign, bovine, deer and goat isolates which were similar to each other. The proteinase isozymes from cultures of the deer and goat isolates were separated by polyacrylamide gel electrophoresis and their molecular weights determined.