Bacterial systematics has undergone several changes and is continuously in a state of flux as our knowledge of microorganisms is far from complete and new information is being added every day.
In 1923 David Hendricks Bergey, professor of bacteriology at the University of Pennsylvania, and four colleagues published a classification of bacteria that could be used for the identification of bacterial species.
The Bergey’s manual of determinative bacteriology
- It has been a widely used reference since the publication of the first edition in 1923.
- Multiple editions of Bergey’s Manual of Determinative Bacteriology, published between 1923 and 1994, organized bacteria in groups by phenotypic characteristics, with no attempt to sort out higher phylogenetic relationships.
- They were very useful for identifying unknown bacterial cultures, however. In the lab, the most recent edition of Bergey’s Manual of Determinative Bacteriology, published in 1994 and reprinted in 2000, is used to identify the isolates.
- The first edition of Bergey’s Manual of Systematic Bacteriology, which came out in four volumes from 1984 through 1989, attempted to organize bacterial species according to known phylogenetic relationships, an approach that continued with a second edition, published in five volumes from 2001 through 2012.
- The organization of Bergey’s Manual of Systematic Bacteriology makes it impractical for helping place unknown bacteria into major taxa, but it contains far more detail on the families, genera, and species and is far more up to date than the Determinative manual.
- The manual does not classify bacteria according to evolutionary relatedness but provides identification (determining) schemes, based on such criteria as cell wall composition, morphology, differential staining, oxygen requirement, and biochemical testing.
- In this volume, bacteria are assigned 19 parts based primarily on the following features energy and carbon source, mode of locomotion, morphology and gram stain reaction, gaseous requirement, and endospore formation ability.
- The edition was published by Wilkins and Baltimore Company of USA.
Bergey’s Manual of Systematic Bacteriology
From 1984, Bergey’s Manual was renamed Bergey’s Manual of Systematic Bacteriology is being published in separate volumes.
This manual includes 35 sections based on characters like general shape, morphology, gram staining, presence of endospore, motility, oxygen relationships, mode of energy production.
The manual includes four divisions of the kingdom Prokaryotae.
- Gracilicutes (gram -ve cell wall)
- Firmicutes (gram + ve cell wall other than actinomycetes)
- Tenericutes (bacteria lacking cell wall other than actinomycetes) and
- Mendoricutes (bacteria lacking peptidoglycan in their cell wall like Archaebacteria).
After 1984, the year of publication of the first volume of Bergey’s manual of systematic bacteriology much work has been done on sequencing of rRNA, DNA, and proteins which has made the phylogenetic analysis of prokaryote feasible.
As a consequence, the second edition of Bergey’s manual is largely phylogenetic rather than phonetic and thus quite different from the first edition and the second edition is published in five volumes.
It has more ecological information about individual taxa.
The second edition does not group all the clinically important prokaryotes together as the first edition; instead, pathogenic sps will be placed phylogenetically and thus scattered throughout the following five volumes.
1: The Archaea, and the deeply branching and phototrophic bacteria.
2: The Proteobacteria
3: The low G + C gram + ve bacteria
4: The high G + C gram + ve bacteria
5: The Planctomycetes, Spirochaetes, Fibrobacteres, Bacteroidetes and Fusobacteria.
- The classification presented in 9th eds. of Bergey’s manual of determinative bacteriology (1994) is specially designed to be used for the identification of bacteria and is different from the classification system presented in Bergey’s manual of systematic bacteriology.
- In this edition, bacteria have been characterized into 35 groups under the above 4 major categories. The first category includes groups 1 to 16 (ex. Spirochaetes, sulfate and sulfur-reducing bacteria, rickethesias, and chlamydias)
- The second category includes groups 17 to 29 (ex. Gram-positive cocci, endospore-forming gram-positive rods, and cocci, non-sporing gram-positive rods)
- The third category includes group 30 (Mycoplasma).
- The last or fourth category includes group 31 to 35 (Ex. Methanogens, Archaeal sulfate reducers, extremely halophiles, cell wall less archaebacteria)
- The most recent revision of Bergey’s manual divides bacteria into four divisions (or phyla) according to the characteristics of cell wall which division is subdivided into sections to such characters like gram stain reactions, cell shape, cell arrangements, oxygen requirement, motility, and nutritional and metabolic properties.
- Each section consists of a number of genera. In some sections, genera are grouped into families and orders in other sections, they are not.
Gram -ve bacteria- Group 1-16
Ex – Spirochaetes
- Sulfate & sulphur reducing bacteria
- Anoxygenic phototrophic bacteria
- Oxygenic phototrophic bacteria
- Aerobic chemolithotrophs
- Budding bacteria
- Sheathed bacteria
- Non-photosynthetic non fruiting gliding bacteria
- Fruiting gliding bacteria
Gram +ve bacteria- Group 17-29
Ex – gram-positive cocci
- Endospore-forming gram-positive rods and cocci
- Non-sporing gram-positive rods.
- Non-cardiform actinomycetes
- Genera with multilocular sporangia
- Streptomycetes and related genera
- Other genera
lacking cell wall group- 30
Archaebacteria- Group 31-35
- Archaeal sulfate reducer
- Extremely halophytes
- Cell wall less archaebacteria
- Extremely thermophilic and hyperthermophilic sulfur metabolizers
Bergey’s manual of systematic bacteriology has four volumes that contain the bacteria considered to be of practical importance and in medicine, or those that illustrate biologically unusual or interesting principles. The four volumes are:-
- Vol 1: It include gram -ve bacteria (section 1-11) (1984)
- Vol 2: It include gram +ve bacteria, photrophic and other specialized bacteria including gliding bacteria (section 12-17) (1986)
- Vol 3: It includes bacteria with unusual cell wall like Archae-bacteria (section 18-25) (1989)
- Vol 4: It include Actinomycetes and other filamentous bacteria (section 26 – 33) (1991)
All four volumes contain the organism with the prokaryotic or primordial nucleus and are kept in single kingdom Prokaryote.
- Trivedi P.C., Pandey S, and Bhadauria S. (2010). Textbook of Microbiology. Pointer Publishers; First edition
- Sastry A.S. & Bhat S.K. (2016). Essentials of Medical Microbiology. New Delhi : Jaypee Brothers Medical Publishers.
- Jeffery C. Pommerville. Alcamo’s Fundamentals of Microbiology (Tenth Edition). Jones and Bartlett Student edition.
- Gerard J. Tortora, Berdell R. Funke, Christine L. Case. Pearson – Microbiology: An Introduction. Benjamin Cummings.