๐Ÿ”ฌ Spotting

Application of phages to an immature bacterial lawn by dropping a small volume, such as 10 µl, onto the surface of a plate.

by Stephen T. Abedon Ph.D. (abedon.1@osu.edu)

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About this entry: Spotting is one of a growing set of phage biology and phage therapy terms defined here. For more phage terms, see Abedon, S.T. (2025). Phage Therapy Annotated Glossary. Preprints.org. 10.20944/preprints202508.0347.v1

phage.org/terms/spotting.html  ·  Abedon’s Books  ·  DOI: 10.5281/zenodo.20173633

How can I improve this page?  contact: terms@phage.org

Spotting: Application of phages to an immature bacterial lawn by dropping a small volume, such as 10 µl, onto the surface of a plate.

Discussion

<p>Spotting should not be confused with plaquing, even though spotting can be a means of generating plaques. In particular, a spot in which clearing is confluent (effectively no class="bap-term">bacteria across the area of the spot) is not a plaque, and this is because while a plaque starts with one or only a few phages and is formed via repeated rounds of phage infection and bacterial lysis, a spot that starts with numerous phages (as is often the case) produces confluent clearing mostly or solely through inhibition of bacterial replication rather necessarily via lysis of an otherwise visible bacterial lawn.

Importantly, "spot" and "plaque" are not equivalent terms – with spots in particular not plaques – and these terms consequently should not be used interchangeably. A spot in particular is much more equivalent to a zone of inhibition, that is, of wikipedia.org/wiki/Bacterial_lawn" target="_blank" class="bap-term">bacterial lawn formation, than is a plaque. volumes, etc.>

External links

How to cite this page

Abedon, S.T. (2026). Phage Terms. https://terms.phage.org  ·  10.5281/zenodo.20173633

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Spotting — terms.phage.orgphage.org — Stephen T. Abedon — Version 2026.05.14