Bacteriology is the study of bacteria, small cells that live an independent existence and play important roles in the biosphere. Structurally, bacteria are prokaryotic cells and comprise two major phylogenetic lineages, Bacteria and Archaea. The science of bacteriology developed from investigations of the nature of infectious disease, and medical bacteriology remains a major area of emphasis in microbiology today. Bacteriology also played a major role in the development of molecular biology and genetics, and bacteria have traditionally been used as experimental tools for addressing seminal questions in basic biological research. More recently, bacteria have been harnessed to produce valuable commercial products and clean up the environment. Unlike higher organisms, bacteria are absolutely essential for maintaining the biosphere and are the foundation upon which all higher life on Earth is supported.

Key Concepts:

  • The science of bacteriology deals with Earth's tiniest living cells, the Bacteria and Archaea, collectively called prokaryotes.

  • Using key genes shared by all cells, bacteriological studies have revealed the evolutionary relationships of all life on Earth.

  • Bacteriology encompasses many subdisciplines including in particular the study of infectious diseases.

  • Bacteriology spawned the field of molecular biology and gave birth to the genomics revolution in biology.

  • Industrial microbiology and biotechnology employ bacteria to make products of commercial value.

Keywords: bacteriology; microbiology; prokaryotes; Bacteria; Archaea; microbial evolution

Figure 1.

Cell structure of (a) prokaryotic and (b) eukaryotic cells. Note the presence of membrane‐enclosed organelles (nucleus, mitochondria and chloroplasts) in the eukaryotic cells, absent from cells of Bacteria and Archaea. Chloroplasts are only present in photosynthetic eukaryotic cells.

Figure 2.

The phylogenetic tree of life. This tree depicts the evolutionary relationships of cells based on comparative ribosomal RNA gene sequencing. The tree clearly reveals the three domains of life: the Bacteria, the Archaea and the Eukarya.


Further Reading

Garrity GM (ed.) (2012) Bergey's Manual of Systematic Bacteriology, 2nd edn, vols. 1–5. New York, NY: Springer.

Greenwood D, Slack RCB, Barer MR and Irving WL (2012) Medical Microbiology, 18th edn. London: Churchill Livingstone.

Lesk AM (2012) Introduction to Genomics, 2nd edn. Oxford: Oxford University Press.

Madigan MT, Martinko JM, Bender KS, Buckley DH and Stahl DA (2014) Brock Biology of Microorganisms, 14th edn. San Francisco, CA: Benjamin Cummings/Pearson.

Reece JB, Urry LA, Cain ML et al. (2011) Campbell Biology, 9th edn. San Francisco, CA: Benjamin Cummings/Pearson.

Thieman WJ and Palladino MA (2012) Introductory Biotechnology, 3rd edn. San Francisco, CA: Benjamin Cummings/Pearson.

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Madigan, Michael T(Oct 2014) Bacteriology. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0000449.pub2]