Device and method for detecting antibiotic inactivating enzymes

Abstract

The present invention provides a method of determining the antibiotic susceptibility of a microorganism comprising the following steps. First, a culture of the microorganism whose susceptibility is to be determined is admixed with an antibiotic to which susceptibility is to be assayed, and a permeabilizing agent for the microorganism present in a non-growth-inhibiting microorganism-permeabilizing effective amount to form an assay culture. Next, the assay culture is incubated under appropriate culture conditions and for a time sufficient to determine the susceptibility of the microorganism to the antibiotic. In another aspect, the present invention provides an improved method for antibiotic susceptibility testing of a microorganism in a culture by admixing the culture with an antibiotic to which susceptibility is to be assayed, and incubating the culture for a time sufficient to determine the susceptibility of the microorganism to the antibiotic, the improvement comprising admixing the culture with a permeabilizing agent for the microorganism present in a non-growth inhibiting microorganism-permeabilizing effective amount.

We claim:  
     
         1 . A method of determining the antibiotic susceptibility of a microorganism comprising the steps of: 
 a) admixing a culture of the microorganism whose susceptibility is to be determined with an antibiotic to which susceptibility is to be assayed, and a permeabilizing agent for the microorganism present in a non-growth-inhibiting microorganism-permeabilizing effective amount to form an assay culture; and    b) incubating said assay culture under appropriate culture conditions and for a time sufficient to determine the susceptibility of the microorganism to said antibiotic.    
     
     
         2 . The method according to  claim 1  wherein said permeabilizing agent is dissolved or dispersed in a carrier.  
     
     
         3 . The method of  claim 1  wherein the permeabilizing agent is a buffer solution.  
     
     
         4 . The method of  claim 3  wherein said buffer solution is Tris/EDTA.  
     
     
         5 . The method of  claim 2  wherein said carrier is a solid carrier.  
     
     
         6 . The method of  claim 5  wherein said solid carrier is a paper disk.  
     
     
         7 . The method of  claim 2  wherein said carrier is a liquid carrier.  
     
     
         8 . The method of  claim 1  wherein said culture is provided on a solid growth medium.  
     
     
         9 . The method of  claim 1  wherein said culture is provided in a liquid growth medium.  
     
     
         10 . The method of  claim 5  wherein the culture is provided on a solid growth medium.  
     
     
         11 . The method of  claim 2  wherein said carrier is a solid carrier, said culture is provided on a solid growth medium, said antibiotic is provided on a solid support, and said admixing is by contacting said culture with said solid carrier and said antibiotic provided on a solid support.  
     
     
         12 . An improved method for antibiotic susceptibility testing of a microorganism in a culture by admixing the culture with an antibiotic to which susceptibility is to be assayed, and incubating the culture for a time sufficient to determine the susceptibility of the microorganism to the antibiotic, the improvement comprising admixing said culture with a permeabilizing agent for the microorganism present in a non-growth inhibiting microorganism-permeabilizing effective amount.  
     
     
         13 . The method of  claim 12  wherein said permeabilizing agent is a buffer solution.  
     
     
         14 . The method of  claim 13  wherein said buffer solution is Tris/EDTA.  
     
     
         15 . The method  claim 12  wherein said permeabilizing agent is dissolved or dispersed in a carrier.  
     
     
         16 . The method of  claim 15  wherein said carrier is a solid carrier.  
     
     
         17 . The method of  claim 16  wherein said solid carrier is a paper disk.  
     
     
         18 . The method of  claim 15  wherein said carrier is a liquid carrier.