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A simple micro-growth assay for enumerating bacteria.

Jeffrey D Brewster
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Abstract

A simple method for nonspecific determination of bacteria concentrations in a variety of liquid samples was developed. The assay was based on the time required for a sample grown in liquid media to reach a threshold turbidity. Samples were combined with media in a covered 96-well microwell plate and the turbidity was monitored in real time as the bacteria grew in a temperature-controlled plate reader. A significant problem with growth in microwells was condensation on the cover, which prevented accurate turbidity measurement. This problem was overcome by coating the cover with a small amount of surface-active agent. Salmonella and E. coli concentrations could be determined with a relative error of approximately 20% at levels from 10 to 10(6) cells/ml (eight replicates). An assay of 10 samples with standards required 10 min to set up and 20 min for data processing using a computer spreadsheet program. Growth time at 37 degrees C ranged from 4 h for samples at 10(7) cells/ml to 16 h for samples at 10 cells/ml.

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AlgorithmsBacteriaBacteriological TechniquesBinding Sites, AntibodyCalibrationCell DivisionColony Count, MicrobialSalmonella enteritidisJournal Article

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Jeffrey D Brewster. 2003. A simple micro-growth assay for enumerating bacteria.. https://doi.org/10.1016/s0167-7012(02)00226-9

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