Bergey's Classification of Bacteria

Bergey’s Manual of Systematic Bacteriology is a manual referring to the taxonomy of prokaryotic bacteria. It was prepared by the American bacteriologist, David Hendricks Bergey in 1923. It is a manual that deals with the identification of bacteria. It has been published in 9 editions.

The first eight editions were published under the name ‘Bergey’s Manual of Determinative Bacteriology’. In the 9th edition, it was renamed as ‘Bergey’s Manual of Systematic Bacteriology’ and was published in four volumes in 1984, 1986, 1989 and 1991.

It is highly regarded by bacteriologists as this manual is continuously updated with successive editions and helps in bacterial taxonomy and research.

The manual classifies bacteria on the basis of their functional and structural attributes and arranges the organisms into familial orders. In recent years, empirical evidence has also been considered in this classification.

Note: Since 2015, the manual has been replaced with Bergey’s Manual of Systematic of Archaea and Bacteria and is available online.


The 1980 edition of the manual took into consideration the relationship between organisms along with an expanded scope in bacterial taxonomy. The set of four volumes contains:

Volume I: It talks about all Gram-negative bacteria and considers them important for medicinal and industrial purposes.

Volume II: It includes all the information about Gram-positive bacteria.

Volume III: It includes information about the remaining Gram-negative bacteria and about Archaea as well.

Volume IV: It talks about filamentous actinomycetes and similar types of bacteria.

The second edition has been published in five volumes, the details of which are given below:

Volume I: It was published in 2001 and talks about the archaea and the branching phototrophic bacteria.

Volume II: It was published in 2005 and gives details about the proteobacteria.

Volume III: It was published in 2009 and gives details about the firmicutes.

Volume IV: It was published in 2011. It mentions the Spirochaetes, Bacteroidetes, Tenericutes (Mollicutes), Chlamydiae, Acidobacteria, Verrucomicrobia, Fusobacteria, Dictyoglomi, Fibrobacteres, Gemmatimonadetes, Lentisphaerae, and Planctomycetes.

Volume V: It was published in 2012 and talks about the actinobacteria.

The First Edition

In the first edition, Bergey classified the kingdom Prokaryotae in four divisions:

  • Gracilicutes: they have a gram-negative cell wall.
  • Firmicutes: they have a gram-positive cell wall.
  • Tenericutes: they do not have a cell wall.
  • Mendosicutes: they lack peptidoglycan in their cell wall and are similar to Archaea.

This classification was entirely based upon gram staining, presence of endospore, general shape, motility, morphology and mode of energy production. While the first edition of Bergey’s manual is entirely phenetic, the second edition was based on phylogenetic characters such as its DNA, RNA and protein.

In the current 9th edition, the manual is designed for identification of bacteria that is very different from the previous editions. In this edition, the bacteria are divided into 35 groups in the four major divisions.

The first division includes groups 1 to 16 (example: spirochete, sulphur-reducing bacteria, chlamydia and rickettsia), the second division includes groups 17 to 29 (example: gram-positive cocci, endospore forming, gram-positive cocci and rods, gram-positive, non-sporing rods), the third division includes group 30 such as Mycoplasma and the the last division includes groups 31 to 35 (example: methanogens, halophiles and archaebacteria).

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