Quantification of antibiotic drug potency by a two-compartment radioassay of bacterial growth

Journal Article · Fri Jun 01 04:00:00 UTC 1990 · Antimicrobial Agents and Chemotherapy; (USA)

DOI:https://doi.org/10.1128/AAC.34.6.1035· OSTI ID:6370043

Boonkitticharoen, V; Ehrhardt, J C; Kirchner, P T ^[1]

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1. Univ. of Iowa, Iowa City (USA)

The two-compartment radioassay for microbial kinetics based on continuous measurement of the {sup 14}CO{sub 2} released by bacterial metabolism of 14C-labeled substrate offers a valuable approach to testing the potency of antimicrobial drugs. By using a previously validated radioassay with gram-positive and gram-negative bacteria, a group of protein synthesis inhibitors was evaluated for their effect on microbial growth kinetics. All tested drugs induced changes in both the slopes and intercepts of the growth curves. An exponential growth model was applied to quantify the drug effect on the processes of bacterial {sup 14}CO{sub 2} liberation and cell generation. The response was measured in terms of a generation rate constant. A linear dependence of the generation rate constant on the dose of spectinomycin was observed with Escherichia coli. Sigmoidal-shaped curves were found in the assays of chloramphenicol and tetracycline. The implications of dose-response curves are discussed on the basis of the receptor site concept for drug action. The assay sensitivities for chloramphenicol and tetracycline were similar to those obtained by the cell counting method, but the sensitivity of the radioassay was at least 10 times greater for spectinomycin.

• OSTI ID: 6370043
• Journal Information: Antimicrobial Agents and Chemotherapy; (USA), Journal Name: Antimicrobial Agents and Chemotherapy; (USA) Vol. 34:6; ISSN AMACC; ISSN 0066-4804
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
BACTERIA
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
CHLORAMPHENICOL
DOSE-RESPONSE RELATIONSHIPS
DRUGS
ESCHERICHIA COLI
GROWTH
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MEMBRANE PROTEINS
METABOLISM
MICROORGANISMS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PROTEINS
RADIOASSAY
RECEPTORS
SENSITIVITY ANALYSIS
TETRACYCLINES
TRACER TECHNIQUES