[Rapid bioluminescent antibiotic susceptibility assay].

Rapid testing of pathogen susceptibility to antibiotics is of great practical value for rational chemotherapy of pyoinflammatory deseases and postoperative complications of microbial etiology. The standard microbiological methods, i.e., the disk diffusion method and the method of serial dilutions are labour- and time-consuming (not less than 18-36 hours). The method of the authors is based on measuring bioluminescence resulting from interaction of adenosine-5'-triphosphate (ATP) and ATP reagent, a standard reaction mixture of firefly luciferase (an enzyme) and luciferin. The bioluminescence intensity is proportional to the ATP concentration in the reaction mixture and the ATP concentration is proportional to the number of the pathogen viable cells in the sample. The bioluminescence intensity value in the pathogen suspension aliquots with and without (control) the antibiotic were compared after the incubation for 5 hours and the coefficient of the microbial cell growth inhibition was calculated. Satisfactory correlation (R2 > 88%) of the results of the bioluminescent assay and the assay with the disk diffusion method and the method of serial dilutions was observed.

[A bioluminescent method of determining antibiotic sensitivity of microbial cells in septic blood]. / Bioliuminestsentnyi metod opredeleniia antibiotikochuvstvitel'nosti mikrobnykh kletok v septicheskoi krovi.

A bioluminescence assay for rapid (5-7 h) determination of susceptibility to antibiotics was applied to samples of septic blood and optimized. The method comprises hemolysis of blood, reduction of osmolarity by adding concentrated nutritive media, and further incubation of the samples in the presence or absence of therapeutic doses of the antibiotic examined. Growth of bacteria is estimated by the level of bacterial ATP in the sample, which is determined by a bioluminescence assay. Hemolysis and further incubation of samples in nutrition media reduced the concentration of nonbacterial ATP to a level that did not interfere with the determination of bacterial ATP. There was a positive correlation between the levels of resistance to antibiotics determined by the bioluminescence assay and standard plate counts.

[The ATP content of the neutrophils and whole blood in the inhabitants of regions in the Altai Territory subjected to nuclear testing exposure]. / Soderzhanie ATF v neitrofilakh i tsel'noi krovi u zhitelei raionov Altaiskogo kraia, podvergshikhsia vozdeistviiu iadernykh ispytanii.

The bioluminescent method was used in the studies of the influence of ionizing irradiation and/or xenobiotics on the content of ATP in RBC and neutrophils of rats, and in whole blood and neutrophils of 80 examined women of Altai Region exposed to ionizing radiation during a series of nuclear tests in Semipalatinsk in 1949-1965. Deviations from the normal ATP content were measured with due to account of the natural variability of a given metabolite. For rats, deviations from the content of ATP in erythrocytes were short-term, those in neutrophils were long-term. For people, a statistically significant increase in the content of ATP in neutrophils as compared to the control was observed. A non-linear correlation between the content of ATP in neutrophils and the calculated dose of radiation was observed. An increase in the ATP content in whole blood, with regard to the control, was not statistically significant for all groups of examined persons.