Medium for the specific detection of resistant microorganisms

Abstract

A method for distinguishing among a first group of microorganisms belonging to a first taxon of Gram negative bacteria, the first group of bacteria exhibiting a mechanism of resistance to a treatment; a second group of microorganisms belonging to a second taxon of Gram negative bacteria, the second taxon of bacteria being different than said first taxon, and exhibiting a mechanism of resistance to a treatment identical to the mechanism of the first group; and a third group of Gram negative bacteria that is not resistant to the treatment.

1 . A method for distinguishing among at least three groups of microorganisms that may be present in a biological sample, the at least three groups comprising:
 a first group of microorganisms belonging to a first taxon of Gram negative bacteria, the first group of bacteria exhibiting a mechanism of resistance to a treatment;   a second group of microorganisms belonging to a second taxon of Gram negative bacteria, the second taxon of bacteria being different than said first taxon, and exhibiting a mechanism of resistance to a treatment identical to the mechanism of the first group; and   a third group of Gram negative bacteria that is not resistant to said treatment, the method comprising:   inoculating a culture medium with the biological sample, wherein the culture medium comprises:
 a first substrate for detecting a first enzymatic or metabolic activity of said first group of microorganisms; 
 a marker for differentiating the first group of microorganisms and the second group of microorganisms, said marker being a substrate for detecting an enzymatic or metabolic activity of said second group of microorganisms; and 
 an antimicrobial that is active on the third group of microorganisms; and 
   distinguishing among any members of the three groups of microorganisms that are present on the culture medium to determine of which group of microorganisms they are members on the basis of their interactions with the first substrate, the markers, and the antimicrobial.   
     
     
         2 . The method according to  claim 1 , wherein:
 the first group of microorganisms is selected from  E. coli  ESBL and HL Case bacteria; and   the second group of microorganisms is selected from KESC ESBL or HL Case bacteria.   
     
     
         3 . The method of  claim 1 , wherein:
 the third group of microorganisms is bacteria not resistant to beta-lactamines and/or cephalosporins.   
     
     
         4 . The method of  claim 1 , wherein:
 the first group of microorganisms is  E. coli  ESBL bacteria;   the second group of microorganisms is KESC ESBL bacteria; and   the third group of microorganisms is bacteria not resistant to beta-lactamines.   
     
     
         5 . The method of  claim 1 , wherein:
 the first group of microorganisms is  E. coli  HL Case bacteria;   the second group of microorganisms is KESC HL Case bacteria; and   the third group of microorganisms is bacteria not resistant to cephalosporins.   
     
     
         6 . The method of  claim 1 , wherein:
 the first group of microorganisms is  E. coli  ESBL bacteria;   the second group of microorganisms is KESC ESBL bacteria;   the third group of microorganisms is bacteria not resistant to beta-lactamines and/or cephalosporins; and   the biological sample further comprises a fourth group of microorganisms that is Proteeae ESBL bacteria.   
     
     
         7 . The method of  claim 1 , wherein:
 the first substrate is a substrate for detecting a beta-glucuronidase or beta-galactosidase enzymatic activity;   the marker is a second substrate for detecting a beta-glucosidase, tryptophanase, or desaminase activity; and   the antimicrobial is ceftazidime.   
     
     
         8 . The method of  claim 1 , wherein:
 the first substrate is a substrate for detecting a beta-glucuronidase or beta-galactosidase enzymatic activity;   the marker is a second substrate for detecting a beta-glucosidase, tryptophanase or desaminase activity; and   the antimicrobial is cefpodoxime and cloxacillin.   
     
     
         9 . The method of  claim 1 , wherein:
 the substrate is a first substrate for detecting a beta-glucuronidase or beta-galactosidase enzymatic activity;   the marker is a second substrate for detecting a beta-glucosidase, desaminase or tryptophanase activity; and   the antimicrobial is ceftriaxone and clavulanic acid.   
     
     
         10 . The method of  claim 1 , wherein:
 the substrate is a first substrate for detecting a beta-glucuronidase or beta-galactosidase enzymatic activity;   the marker is a second substrate for detecting a beta-glucosidase activity;   the antimicrobial is a combination comprising:
 cefpodoxime, 
 cloxacillin, 
 vancomycin, and 
 amphotericin B; and 
   the culture medium further comprises a third substrate for detecting a desaminase activity.   
     
     
         11 . The method of  claim 10 , wherein the antimicrobial further comprises cefsulodine. 
     
     
         12 . The method of  claim 1 , wherein:
 the first group of microorganisms is  E. coli  ESBL bacteria;   the second group of microorganisms is KESC ESBL bacteria;   the third group of microorganisms is bacteria not resistant to beta-lactamines and/or to cephalosporins;   the biological sample further comprises a fourth group of microorganisms that is Proteeae ESBL bacteria;   the first substrate is a substrate for detecting a beta-glucuronidase or beta-galactosidase enzymatic activity;   the marker is a second substrate for detecting a beta-glucosidase activity;   the antimicrobial is a combination comprising:
 cefpodoxime, 
 cloxacillin, 
 vancomycin, and 
 amphotericin B; and 
   the culture medium further comprises a third substrate for detecting a desaminase activity.   
     
     
         13 . The method of  claim 1 , wherein:
 the first group of microorganisms is  E. coli  ESBL bacteria;   the second group of microorganisms is KESC ESBL bacteria;   the third group of microorganisms is bacteria not resistant to beta-lactamines and/or to cephalosporins;   the biological sample further comprises a fourth group of microorganisms that is Proteeae ESBL bacteria;   the first substrate is a substrate for detecting a beta-glucuronidase or beta-galactosidase enzymatic activity;   the marker is a second substrate for detecting a beta-glucosidase activity;   the antimicrobial is a combination comprising:
 cefpodoxime, 
 cloxacillin, 
 vancomycin, 
 amphotericin B, and 
 cefsulodine; and 
   the culture medium further comprises a third substrate for detecting a desaminase activity.