Bacterial Colony Counting

Colony forming unit cfu or cfu is a measure of viable bacterial or fungal cells.

Bacterial colony counting.

Nine obviously different colonies are numbered. Colony counters are used to estimate a liquid culture s density of microorganisms by counting individual colonies on an agar plate slide mini gel or petri dish. Typical applications include ames testing bacterial mutation assays and e. Therefore an important step in many cm protocols toward the estimation of the nature and degree of infections is bacterial colony counting bcc.

Different species of bacteria can produce very different colonies. The number of colonies on culture plates also called colony forming units cfu is used in clinical microbiology as a rough estimate of the number of viable bacteria in a sample. The colony counter app gives you a count estimate you can then manually refine. A colony forming unit cfu cfu cfu is a unit used in microbiology to estimate the number of viable bacteria or fungal cells in a sample.

For example a urinary tract bacterial infection. Viable is defined as the ability to multiply via binary fission under the controlled conditions. As with hemocytometers or counting chambers cultures need to be heavily diluted prior to plating. The microbial concentration is determined by counting the colonies on a part of the petri dish where they are easily countable and dividing this count by the appropriate volume.

Some colony types recur in various areas of the plate note 3 and 4. Snap a picture with your phone and you can make counting an out of lab experience. Bacterial colony counts made from plating dilutions of bacteria are useful to estimate the strength of bacterial infections.