Classification of Bergey’s manual of Systematic bacteriology
Bergey’s Manual of Systematic Bacteriology is the main resource for identification and
characterization of bacteria. The manual was first published as Bergey's Manual of Determinative
Bacteriology in 1923 by David Hendricks Bergey. It is used to classify bacteria based on their structural
and functional attributes by arranging them into specific familial orders. Bergey’s manual of systematic
bacteriology includes phylogenetic information based on the 16srRNA sequence databases. The first
edition was publishedin 1984 with 4 volumes. The second edition was published in 2001 with five
volumes.
Volume 1: Archaea and the deeply branching and phototropic bacteria.
Volume 2: Proteobacteria – includes all Gram negative bacteria
Volume 3: Firmicutes – includes all low G+C content Gram positive bacteria
Volume 4: Bacteroidetes, Spirochaetes, Tenericutes (Mollicutes), Acidobacteria, Fibrobacteres,
Fusobacteria, Dictyoglomi, Gemmatimonadetes, Lentisphaerae, Verrucomicrobia, Chlamydiae, and
Planctomycetes
Volume 5 : Actinobacteria - includes high G+C content Gram positive filamentous bacteria
Volume 2: PROTEOBACTERIA
This phylum includes all Gram negative bacteria. It is the largest phylum that includes most of the well
known clinically and industrially important bacteria. It has 6 classes.
1.
2.
3.
4.
5.
6.
Alphaproteobacteria
Betaproteobacteria
Gammaproteobacteria
Deltaproteobacteria
Zetaproteobacteria
Epsilonproteobacteria
Alphaproteobacteria :
The second largest phylum under proteobacteria. There are 10 orders. Most species are obligate
aerobes or facultative aerobes and many are oligotrophic. Some of the orders include
Order
Genus
Rhizobiales
Rhizobium , Nitrobacter
Rickettsiales-
Ricketssia, Wolbachia
Rhodobacterales Rhodobacter
Rhodospirillales Glucanobacter, Acetobacter, Azospirillum
Betaproteobacteria:
With nearly 500 described species, the Betaproteobacteria are the third largest class of Proteobacteria.
The Betaproteobacteria contain an immense amount of functional diversity. A total of six orders are
included here. Some of them are:
Hydrogenophilales – Example genus : Thiobacillus
Neisseriales- Example genus : Neisseria
Nitrosomonadales- Example Genus : Nitrosomonas
Gammaproteobacteria:
The Gammaproteobacteria are the largest and most diverse class of Proteobacteria, containing nearly
half of the characterized species in the phylum. This class includes many of the well known human
pathogens. The class contains more than 1500 characterized species among its 15 orders. The Order
enterobacteriales consists of enteric bacteria, relatively homogeneous phylogenetic group within the
Gammaproteobacteria and consist of facultatively aerobic, gram-negative, nonsporulating rods.
Some of the important orders include:
Order Enterobacteriales: Genus - Escherichia coli, Salmonella , Enterobacter, Klebsiella, Proteus
Order Pseudomonadales: Genus – Pseudomonas
Order: Vibrionales: Genus - Vibrio
Order Xanthomonadales: Genus - Xanthomonas
Delta, Epsilon and Zeta proteobacteria:
The Deltaproteobacteria are primarily sulfate- and sulphur reducing bacteria and bacterial predators.
Epsilonproteobacteria, contain many species that oxidize the H2S produced by the sulfate and sulfur
reducers. The final class of Proteobacteria, the Zetaproteobacteria, contains only one characterized
species (the iron oxidizer Mariprofundus ferrooxydans) .
Deltaproteobacteria: Example – desulphobacter, myxococcales
Epsilonproteobacteria :Example – campylobacter, helicobacter
Zetaproteobacteria: Example – Mariprofundus ferrooxydans
Volume 3 :FIRMICUTES
Firmicutes are low GC content Gram positive bacteria. There are three major orders under firmicutes :
• Lactobacillales
• Bacillales
• Clostridiales
Order: Lactobacillales
The order Lactobacillales contains the lactic acid bacteria, fermentative organisms that produce lactic
acid as a major end product of metabolism. One important difference between subgroups of the lactic
acid bacteria lies in the pattern of products formed from the fermentation of sugars. One group, called
homofermentative, produces a single fermentation product, lactic acid. The other group, called
heterofermentative, produces other products, mainly ethanol and CO2, as well as lactate.
Eg: Lactobacillus,Leuconostoc
Order: Bacillales:
The order Bacillales typically contains aerobic and facultatively aerobic chemoorganotrophs. Few human
pathogens are found within this group, but the genus Listeria is a notable exception. Several species of
bacillales produce endospores. Eg: Bacillus, Listeria
Order Clostridiales:
A number of clostridia are saccharolytic and ferment sugars, producing butyric acid as a major end
product. The main habitat of clostridia is the soil. Several Closridia are pathogenic andendospore
producing. Eg: botulism is caused by Clostridium botulinum, tetanus by Clostridium tetani, and gas
gangrene by Clostridium perfringens.
Volume 5 : Actinobacteria
The other major group of gram-positive bacteria is the Actinobacteria, which form their own
phylum within the Bacteria. The Actinobacteria contain rod-shaped to filamentous and primarily aerobic
bacteria that are common inhabitants of soil and plant materials. For the most part they are harmless
commensals, species of Mycobacterium (for example, Mycobacterium tuberculosis) being notable
exceptions. Some are of great economic value in either the production of antibiotics or certain fermented
dairy products. While there are nine orders of Actinobacteria, the vast majority of species belong to the
order Actinomycetales.
Examples in Order Actinomycetales:
• Mycobacterium tuberculosis : pathogen known to cause tuberculosis
• Propionibcaterium sp: popular for swiss cheese production
• Streptomyces griseus : production of antibiotic streptomycin
Volume 1 :Archaea
Archaea include species that carry out chemoorganotrophic or chemolithotrophic metabolisms,
and both aerobic and anaerobic species are common Many metabolic traits of archaeal species are also
found in Bacteria but others are unique to Archaea. Methanogens, for example, are Euryarchaeota that
conserve energy from the production of methane. Archaea are also well known for containing many
species of extremophiles, including species that are hyperthermophiles (organisms with growth
temperature optima above 80°C), halophiles, and acidophiles.
Examples:
• Extremely halophilic archaea : salt loving – Halococcus
• Methanogens – bacteria that produce methane- Methanospirillum, Methanobacterium
• Extremely Acidophilic bacteria – Thermoplasma acidophilum
• Hyperthermophilic bacteria - Thermococcus, Pyrococcus
Volume 4
Volume 4 of Bergey’s manual contains several phyla with diverse characteristics. Among them are
tenericutes, bacteriodetes, chlamydiae,planctomycetes and many other phyla.
The Tenericutes, are bacteria that lack cell walls. This group is often called the mycoplasmas because
Mycoplasma, a notable genus containing human pathogens. Mycoplasmas typically live in close
association with animal and plant hosts and this may eliminate the need for a gram-positive cell wall.
Mycoplasmas resemble protoplasts (bacteria treated to remove their cell walls), but they are more
resistant at least partially due to the presence of sterols in their membrane.
The phylum Bacteroidetes contains more than 700 characterized species spread across four orders.
They are gram-negative nonsporulating rods; species are typically saccharolytic and can be aerobic or
fermentative. Eg: Flavobacterium .
The phylum Chlamydiae contains a single order, the Chlamydiales. The entire phylum consists of
obligate intracellular parasites of eukaryotes. Eg: Chlamydia.
Planctomycetes are gram-negative bacteria. Planctomycetes are unusual among bacteria because
their cell walls lack peptidoglycan and hence are resistant to antibiotics. Eg: Planctomycetes.
Source: Brock biology of microorganisms