Radiometric assay of bacterial growth: analysis of factors determining system performance and optimization of assay technique

Journal Article · Sun Feb 01 00:00:00 EST 1987 · J. Nucl. Med.; (United States)

OSTI ID:6648075

Boonkitticharoen, V; Ehrhardt, J C; Kirchner, P T

A quantitative technique for the measurement of /sup 14/CO/sub 2/ released from a bacterial culture was evaluated. The technique uses liquid scintillation counting to record /sup 14/CO/sub 2/ accumulation on a fluor-impregnated filter paper within a double-chambered scintillation vial that also houses the bacterial growth medium. We have successfully identified and corrected the major causes for a variably low detection efficiency, and also established the optimum mixture of reagents for the detection system. Incorporation of Triton X-100 into the scintillation fluid used for the detector reduced the variability between identical assays in a single batch from 50% to 5%, and, in conjunction with an increase in the scintillator concentration, raised the counting efficiency from 30% to 70-88%. The response of the improved detector is linear over a wide range of count-rates. Another significant modification was the interchange of growth and detector chambers. Overall, a 40-fold increase in count-rate during the exponential phase of bacterial growth was obtained by improving /sup 14/CO/sub 2/ detection efficiency, increasing the rate of /sup 14/CO/sub 2/ transfer from liquid to gas phases and enlarging the growth supporting capacity of the detector system. The minimum detection time for bacterial growth was shortened and the exponential phase of bacterial proliferation was lengthened by at least 2 hr. High counting efficiency, precision, and linearity make the improved detector a sensitive and reliable tool for radiometry of bacterial growth and metabolism.

• Research Organization: Univ. of Iowa, Iowa City
• OSTI ID: 6648075
• Journal Information: J. Nucl. Med.; (United States), Vol. 2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BACTERIA
RADIOASSAY
SCINTILLATION COUNTING
CARBON 14 COMPOUNDS
CARBON DIOXIDE
FILTRATION
GROWTH
TRACER TECHNIQUES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
COUNTING TECHNIQUES
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MICROORGANISMS
OXIDES
OXYGEN COMPOUNDS
SEPARATION PROCESSES
550701* - Microbiology- Tracer Techniques