RAPID TEST FOR DETERMINING THE INTRACELLULAR RHODANESE ACTIVITY OF VARIOUS BACTERIA

A simple, reproducible technique with potential taxonomic application was developed for the rapid detection of rhodanese activity in gram-negative and gram-positive bacteria. The method requires suspension of the growth from three colonies in a solution of lysozyme and ethylenediaminetetraacetic acid for 60 min. After cell lysis, the presence of rhodanese activity is determined colorimetrically by measuring the amount of thiocyanate formed from thiosulfate and potassium cyanide by use of ferric nitrate. By this technique, a survey of 411 bacterial strains revealed the presence of rhodanese in all test strains of Escherichia coli, Pseudomonas aeruginosa, Acinetobacter, Bordetella, Shigella, and Citrobacter. No activity was detected in Salmonella, Klebsiella, Enterobacter, Serratia, or Proteus species. Randomly selected strains which did not exhibit rhodanese activity were confirmed to be rhodanese-negative by assay of mechanically disrupted cells harvested from 500 ml of growth medium.