Chemiluminescent detection of bacteria: experimental and theoretical limits

Abstract

The limit of sensitivity of the chemiluminescent assay for detection of bacteria by hemeprotein catalysis of luminol oxidation was determined, both experimentally and theoretically, to be no lower than 105 to 106 viable bacteria per ml.

Determination of iron–porphyrin-like complexes at nanomolar levels in seawater

“…Considering that Fe-Py protein are a fraction of the iron protein we found this number is likely an upper limit. For bacteria, direct measurements of hemeprotein (catalase or cytochrome c) have been reported in the range 10 -19 -10 -20 mol cell -1 [ 45,46 ]. Therefore our measurements of the intracellular content of Fe-Py fall in this range.…”

Evaluation of bacterial survival and phagocyte function with a fluorescence-based microplate assay

“…Our initial efforts to compare the rate of killing of S. typhimurium by macrophages from wild-type, iNOS-deficient, and gp91 phox -deficient mice in the same experiments were complicated by the cumbersome nature of existing assays of bacterial survival. Most methods for the quantitation of viable microorganisms, such as dilution and plating (3), disc diffusion (2), microbroth dilution (24), tetrazolium reduction (8,20,26,27), thymidine incorporation (8), chemiluminescence (12), and optical density (28), are limited by sensitivity, precision, complexity, time, cost, and/or the use and disposal of regulated materials. Herein we describe a simple assay that avoids such problems by using a fluorescent indicator to enumerate viable bacteria accurately and semiautomatically over the range of 10 2 to 10 8 per ml in individual wells of 96-well trays.…”