Johnston Laboratories, Inc.

Rodney L Broman

John R Waters

Joseph E Ahnell

Dennis Buda

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.

Method for detecting the presence of biologically active agents

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.

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.

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Falston, MD, United States of America

Rodney L Broman