Patent ID: 6861230

Claim:
A method for determining the susceptibility of a bacteria to a reagent selected from an antibiotic agent or a biostatic agent or a compound suspected of having an antibiotic property or a compound suspected of having a biostatic property, said method comprising the steps of: (i) dividing a culture comprising said bacteria into at least a first sample and a second sample; (ii) incubating said first sample in the presence of said reagent to form a first incubated sample, lysing bacteria in said first incubated sample to form a first lysed-incubated sample, exposing the first lysed-incubated sample to ADP, a source of magnesium ions, luciferin and luciferase, to form a first mixture, and measuring luminescence emitted from said first mixture as an indication of the amount of any adenylate kinase present in the first lysed-incubated sample; (iii) subjecting said second sample to either of the following steps (iii)(a) and (iii)(b); (a) incubating said second sample in the absence of said reagent to form a second incubated sample, lysing bacteria in said second incubated sample to form a second lysed-incubated sample, exposing the second lysed-incubated sample to ADP, a source of magnesium ions, luciferin and luciferase, to form a second mixture, and measuring luminescence emitted from said second mixture as an indication of the amount of any adenylate kinase present in the second lysed-incubated sample; (b) lysing bacteria in said second sample without further incubating said second sample, in the absence of said reagent, to form a first lysed sample, exposing the first lysed sample to ADP, a source of magnesium ions, luciferin and luciferase, to form a third mixture, and measuring luminescence emitted from said third mixture as an indication of the amount of any adenylate kinase present in the first lysed sample; and (iv) comparing the indicated amount of adenylate kinase present in the first lysed-incubated sample with the indicated amount of any adenylate kinase present in the second lysed-incubated sample or the first lysed sample as a determination of the susceptibility of said bacteria to the reagent, wherein (a) said bacteria are susceptible to said reagent when the indicated amount of adenylate kinase in said second lysed-incubated sample is greater than the indicated amount of adenylate kinase in said first lysed-incubated sample, the magnitude of the difference between said indicated amounts being indicative of the degree of susceptibility of said bacteria to said reagent, wherein a greater difference is indicative of a greater susceptibility, and (b) when the magnitude of the difference between the indicated amount of adenylate kinase in said first lysed-incubated sample is greater than the indicated amount of adenylate kinase in said first lysed sample, then the magnitude of the difference indicates the degree of susceptibility of said bacteria to said reagent, wherein a smaller difference is indicative of a greater susceptibility.