Method for detecting streptococcus agalactiae using esterase activity

Abstract

A reaction medium that includes (i) an esterase enzyme substrate that Streptococcus agalactiae is not capable of using at less than 18 hours after inoculation, (ii) at least one enzymatic substrate selected from β-cellobiosidase substrates, N-acetylglucosaminidase substrates, and a β-glucosidase substrates, and (iii) a phosphatase substrate.

What is claimed is: 
     
         1 . A reaction medium, comprising:
 (i) an esterase substrate that  Streptococcus agalactiae  is not capable of using at less than 18 hours after inoculation;   (ii) at least one enzymatic substrate selected from β-cellobiosidase substrates, N-acetylglucosaminidase substrates, and β-glucosidase substrates; and   (iii) a phosphatase substrate.   
     
     
         2 . The reaction medium according to  claim 1 , wherein the at least one enzymatic substrate is a β-cellobiosidase substrate. 
     
     
         3 . The reaction medium according to  claim 1 , wherein the at least one enzymatic substrate is an N-acetyl-glucosaminidase substrate. 
     
     
         4 . The reaction medium according to  claim 1 , wherein the at least one enzymatic substrate is a β-glucosidase substrate. 
     
     
         5 . The reaction medium according to  claim 4 , wherein the β-glucosidase substrate is an indoxyl substrate. 
     
     
         6 . The reaction medium according to  claim 1 , wherein the esterase substrate is selected from derivatives of indoxyl octanoate, indoxyl nonanoate, and indoxyl decanoate. 
     
     
         7 . The reaction medium according to  claim 1 , wherein a concentration of each enzymatic substrate is between 10 and 2000 mg/l. 
     
     
         8 . The reaction medium according to  claim 1 , further comprising a phosphate solution. 
     
     
         9 . The reaction medium according to  claim 8 , wherein the phosphate solution is Na 2 HPO 4  or K 2 HPO 4 . 
     
     
         10 . The reaction medium according to  claim 1 , further comprising a mixture of inhibitors for inhibiting or limiting growth of unwanted strains. 
     
     
         11 . The reaction medium according to  claim 10 , wherein the inhibitors are antibiotics. 
     
     
         12 . The reaction medium according to  claim 11 , wherein the antibiotics are aztreonam and amphotericin B.