Organisms

Bacteria

One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.

National Library of MedicineMedical Subject Headings2026

Structured Summary

Abstract

One of the three domains of life (the others being Eukarya and ARCHAEA), also called Eubacteria. They are unicellular prokaryotic microorganisms which generally possess rigid cell walls, multiply by cell division, and exhibit three principal forms: round or coccal, rodlike or bacillary, and spiral or spirochetal. Bacteria can be classified by their response to OXYGEN: aerobic, anaerobic, or facultatively anaerobic; by the mode by which they obtain their energy: chemotrophy (via chemical reaction) or PHOTOTROPHY (via light reaction); for chemotrophs by their source of chemical energy: CHEMOLITHOTROPHY (from inorganic compounds) or chemoorganotrophy (from organic compounds); and by their source for CARBON; NITROGEN; etc.; HETEROTROPHY (from organic sources) or AUTOTROPHY (from CARBON DIOXIDE). They can also be classified by whether or not they stain (based on the structure of their CELL WALLS) with CRYSTAL VIOLET dye: gram-negative or gram-positive.

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Classification

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Synonyms

1 entry terms
  • Eubacteria

MeSH Record

Aspects Covered

14 allowable subheadings

Indexed with the subheadings chemistry, classification, cytology, drug effects, enzymology, genetics, growth & development, immunology, isolation & purification, metabolism, pathogenicity, radiation effects, ultrastructure, virology.

MeSH Record

Indexing Annotation

general; prefer specifics; relation to bacterial disease: Manual 22.12-22.16; presence of bacteria in organs vs infection: Manual 22.11; note many precoordinated bacterial - terms (BACTERIAL PROTEINS; ANTIBODIES, BACTERIAL; etc); "coliform bacteria" = COLIFORM BACILLI see ENTEROBACTERIACEAE; presence of bacteria in blood = BACTEREMIA: see note there

MeSH Record

History Note

1963

MeSH Hierarchy

Tree Number

  1. B03w

AMA Style

References

  1. National Library of Medicine. Bacteria. Medical Subject Headings (MeSH). 2026. Unique ID D001419. http://id.nlm.nih.gov/mesh/2026/D001419
  2. Bacteria. In: Wikipedia. https://en.wikipedia.org/wiki/Bacteria
  3. Bacteria. In: Wikidata. https://www.wikidata.org/wiki/Q10876