Abstract: The detection of "significant bacteriuria" in a urine sample is accomplished by measuring the head space gas oxygen consumption in a closed vial system. A sample to be tested is introduced into a sealed vial containing a growth medium and the head space gas oxygen concentration initially measured. After a suitable incubation period, the oxygen concentration above the sample is again measured using a closed sample loop. A decrease in the head space oxygen concentration below a predetermined level indicates the presence of a significant quantity of oxygen consuming microorganisms in the sample.

Abstract: A sample of material to be tested for the presence of biologically active agents, such as bacteria, is introduced into a sealable container partially filled with a culture medium comprising a .sup.13 C-labeled fermentable substrate, the remainder of the container being filled with a culture gas, the container and its contents are subjected to conditions conducive to biological activity for a predetermined period sufficient for fermentation of the medium to produce carbon dioxide after which the ratio of .sup.13 CO.sub.2 to .sup.12 CO.sub.2 in the culture gas in the container is determined and compared to the initial ratio of .sup.13 CO.sub.2 to .sup.12 CO.sub.2 in the culture gas in order to detect any differences indicating the presence of biologically active agents in the sample.

Abstract: A sample of material to be tested for the presence of oxygen consuming bacteria is introduced into a sealable container partially filled with a culture medium; the remainder of the container being filled with an oxygen containing gas, the container being connected to means for sensing the production of a vacuum therein. The container and its contents are subjected to conditions conducive to bacterial growth for a predetermined period sufficient for growth of bacteria to consume some of the oxygen, during which time the pressure of the gas in the container is monitored and compared to the initial pressure in order to detect the production of a vacuum due to consumption of oxygen by bacteria from the test sample, thereby indicating the presence or absence of oxygen consuming bacteria in the sample of test material.

Abstract: A method of measuring the level of an aminoglycoside antibiotic, such as gentamicin, tobramycin or amikacin, in blood serum or plasma comprising incubating an aliquot of blood serum or plasma from a human patient being treated with an aminoglycoside antibiotic in a urea-containing culture medium with a susceptible strain of an adaptive urease producing microorganism corresponding to Proteus rettgeri JLI 03, ATCC No. 31168.

Abstract: A sample of material to be tested for the presence of biologically active agents, such as bacteria, is introduced into a sealable container partially filled with a culture medium; the remainder of the container being filled with a culture gas, the container and its contents are subjected to conditions conducive to biological activity for a predetermined period sufficient for fermentation of the medium to produce at least one gaseous product after which the character of the culture gas in the container is determined and compared to the initial character of the culture gas in order to detect any differences caused by changes in the composition of the culture gas indicating the presence or absence of biologically active agents in the sample.

Abstract: A method for characterization of biological activity comprising providing a plurality of gas-tight cells each having a light-permeable wall section, each cell containing a different .sup.14 C-labeled fermentable substrate, a carbon dioxide absorber and a scintillation compound in intimate proximity to each other remote from said substrate, and an axenic sample of a biologically active material; subjecting said cells to conditions conducive to biological activity and thereafter measuring the light emitted by the scintillation compound as a result of the decay of .sup.14 CO.sub.2 generated by the metabolic action of the biologically active agent in said sample on said substrate and captured by the carbon dioxide absorber. Apparatus is provided comprising a plurality of sterile chambers containing different .sup.

Abstract: The ability of gentamicin to inhibit urease synthesis by a gentamicin susceptible strain of an adaptive urease producing microorganism is employed to provide an assay for the concentration of gentamicin present in the blood of a patient being treated with gentamicin. The gentamicin concentration in the liquid portion of blood is determined by comparing the amount of C.sup.14 O.sub.2 produced by a gentamicin susceptible strain of an adaptive urease producing microorganism from a culture medium containing an aliquot of blood test sample and a measured amount of C.sup.14 urea with the C.sup.14 O.sub.2 produced by that microorganism from controls using known concentrations of gentamicin in blood samples.

Abstract: A sample of materials such as blood, urine, spinal fluid, or the like to be tested for the presence of biological activity is placed into a first sterile container with a suitable growth medium which includes a .sup.14 C carbon containing carbon source (such as .sup.14 C substituted glucose) which is fermentable to produce gaseous .sup.14 CO.sub.2. This first container is placed within a second container which also contains CO.sub.2 -absorbing material associated with a scintillation compound. The gaseous .sup.14 CO.sub.2 generated in the first container diffuses into the outer container where it is absorbed and held in contact with the scintillation compound. The decay of .sup.14 C will cause the scintillation compounds to emit light flashes which can be detected by a scintillation counter. Thus, the presence of .sup.14 CO.sub.2 is detected in the same container in which the reaction is taking place.

Abstract: A sample of material such as blood, urine, spinal fluid, or the like to be tested for the presence of biological activity is placed into a sterile container together with a suitable growth medium which includes a C.sup.14 carbon containing carbon source (such as C.sup.14 substituted glucose) which is fermentable to produce gaseous C.sup.14 O.sub.2. An incubator is provided for exposing the container and its contents to conditions conducive to growth. After a suitable incubation period, a portion of the gaseous atmosphere in the container is withdrawn and analyzed in gaseous form in an ionization chamber for the presence of radioactivity. Valve and conduit means are provided for analyzing a number of samples sequentially.