Bacteria

Bacteria are microscopic, unicellular procaryotic organisms. Traditionally, all procaryotes, that is organisms whose cells lack a nucleus, are members of a single kingdom, which has variously been called Bacteria, Prokaryotae, or Monera, and subdivided into two subkingdoms: Eubacteria and Archaebacteria. Carl Woese ^[1] and others have published evidence that the two procaryotic subkingdoms are distinct ancient lineages. Therefore, Woese proposed that on the one great tree of life, there are three domains: Bacteria (the Eubacteria), Archaea (Archaebacteria), and Eucarya (Eucaryotes). Many species of eubacteria are human pathogens. Archaebacteria are typically found in extreme environments, and have so far not been proven to be human pathogens.

Other names

Synonyms

• Procaryotes
• Monerans

Related terms

• Microbes
• Microorganisms
• Germs

Types

• Eubacteria (sometimes called bacteria)
• Archaebacteria (or archaea)

Classification of Bacteria

Bacteria are usually described or classified based on their requirements for nutrients, energy, and oxygen, on their morphology and staining properties, and on molecular analyses.

Classification Based on Metabolism

Classification based on bacterial metabolic requirements includes energy source, reducing equivalent (electron donor) source, and carbon source for biosynthesis.

Classification Based on Respiration

Respiration is the set of biochemical reactions that convert bonds in organic compounds into bonds in energy-rich molecules (e.g., ATP) and waste products.

• Aerobic respiration uses a cytochrome electron transport system (ETS), and oxygen as the terminal electron acceptor;
• Anaerobic respiration uses a cytochrome ETS, but a different final electron acceptor; and
• Fermentation has organic compounds acting as both electron donors and acceptors, and does not utilize cytochrome ETS.

Culturing bacteria under different conditions can be used to determine their use, requirement and tolerance for oxygen.

• Obligate aerobes - Bacteria that require oxygen. They use oxygen as the terminal electron acceptor. (Aerobic respiration)
• Obligate anaerobes - Bacteria that require an oxygen-free environment (Anaerobic respiration or fermentation)
• Facultative anaerobes - Bacteria that do not require oxygen (anaerobic respiration or fermentation), but can use it (aerobic respiration)
• Aerotolerant bacteria - Bacteria that tolerate, but do not use or require, oxygen (fermentation)
• Microaerophiles - Bacteria that require oxygen (aerobic respiration), but tolerate only low levels of oxygen.

Classification Based on Morphology

• Coccus (spherical grain)
• Bacillus (rod-shaped stick)
• Vibro (curved rods)
• Spirillum (spiral coil)
• Spirochaete (tightly coiled spiral)
• Filamentous bacterium (resembling fungal hyphae)

The Gram stain differentiates bacteria into two groups based on their extracellular structures.

• Gram-postitive bacteria have a thick cell wall.
• Gram-negative bacteria have a thin cell wall and an outer enveloping membrane.

Classification Based on Molecular Data

Classification of bacteria has been greatly revised by analysis of nucleic acid sequences. The sections below contain a classification of bacteria that are human pathogens.

Gram-positive Eubacteria

Actinobacteria

Actinobacteria are high G+C Gram-postive eubacteria.

order: Actinomycetales

• suborder: Actinomycineae
  • family: Actinomyecetaceae
    • Actinomyces israelii (Streptothrix israeli Kruse 1896) Lachner-Sandoval 1898 (actinomycosis)
    • Actinomyces naeslundi Thompson & Lovestedt 1951 (actinomycosis)
    • Actinomyces meyeri (Actinobacterium meyeri Prévot 1938) E.P. Cato et al. 1984 (actinomycosis)
    • Actinomyces odontolyticus Batty 1958 (actinomycosis)
    • Actinomyces viscosus (Odontomyces viscosus Howell et al. 1965) Georg et al. 1969 (actinomycosis)

• suborder: Propionibacterineae
  • family: Propionibacteriaceae
    • Propionibacterium acnes (Bacillus acnes Gilchrist 1900) Douglas & Gunter 1946 (actinomycosis)

• suborder; Micrococcineae
  • family: Cellulomonadaceae
    • Tropheryma whipplei (Tropheryma whippelii 1991) La Scola et al. 2001 (Whipple disease)

• suborder: Streptosporangineae
  • family: Thermomonosporaceae
    • Actinomadura madurae (Streptothrix madurae Vincent 1894) Lechevalier and Lechevalier 1968 (actinomycetoma)
    • Actinomadura pelletieri (Micrococcus pelletieri Laveran 1906) Lechevalier and Lechevalier 1968 (actinomycetoma)
  • Nocardiopsaceae
    • Nocardiopsis dassonvillei (Streptothrix dassonvillei Brocq-Rousseau 1904) Meyer 1976 (actinomycetoma)

• suborder: Streptomycineae
  • family: Streptomycetaceae
    • Streptomyces somaliensis (Indiella somaliensis Brumpt 1906) Waksman and Henrici 1948 (actinomycetoma)

• suborder: Corynebacterineae
  • family: Nocardiaceae
    • Nocardia asteroides (Cladothrix asteroides Eppinger 1891) Blanchard 1896 (nocardiosis, actinomycetoma)
    • Nocardia brasiliensis (Discomyces brasiliensis Lindenberg 1909) Pinoy 1913 (nocardiosis, actinomycetoma)
    • Nocardia otitidiscaviarum Snijders 1924 (nocardiosis, actinomycetoma)
    • Nocardia transvalensis Pijper and Pullinger 1927 (nocardiosis)
    • Rhodococcus equi (Corynebacterium equi Magnusson 1923) Goodfellow & Alderson 1977
  • family: Mycobacteriaceae
    • Mycobacterium leprae Hansen, 1874 (leprosy)
    • Mycobacterium tuberculosis complex
      • Mycobacterium tuberculosis Zopf 1883 (tuberculosis)
      • Mycobacterium africanum Castets et al. 1969 (tuberculosis)
      • Mycobacterium bovis Karlson & Lessel 1970 (tuberculosis)
    • Mycobacterium avium complex (MAC)
      • Mycobacterium avium Chester 1901
      • Mycobacterium intracellulare (Nocardia intracellularis Cuttino and McCabe 1949) Runyon 1965
      • Mycobacterium scrofulaceum Prissick and Masson 1956
    • Mycobacterium fortuitum complex (MFC)
      • Mycobacterium fortuitum da Costa Cruz 1938
      • Mycobacterium chelonae Bergey et al. 1923
    • Mycobacterium kansasii Hauduroy 1955
    • Mycobacterium ulcerans MacCallum et al. 1950 (Buruli ulcer)
    • Mycobacterium abscessus Moore and Frerichs 1953
    • Mycobacterium haemophilum Sompolinsky et al. 1978
    • Mycobacterium marinum Aronson 1926
    • Mycobacterium simiae Karassova et al. 1965
    • Mycobacterium xenopi Schwabacher 1959
  • family: Corynebacteriaceae
    • Corynebacterium diphtheriae (Bacillus diphtheriae Kruse 1886) Lehmann and Neumann 1896 (diphtheria)
    • Corynebacterium minutissimum Sarkany et al. 1962 (erythrasma)
    • Corynebacterium jeikeium Jackman et al. 1988

order: Bifidobacteriales

• family: Bifidobacteriaceae
  • Gardnerella vaginalis (Haemophilus vaginalis Gardner and Dukes 1955) Greenwood and Pickett 1980 (bacterial vaginitis)

Firmicutes

Firmicutes are usually described as low G+C gram-positive Eubacteria, but they also include Eubacteria that lack a cell wall (e.g., Mycoplasma)

class: Bacilli

• order: Lactobacillales
  • family: Streptococcaceae
    • Streptococcus pyogenes Rosenbach 1884 (Lancefield Group A; β-hemolytic) (scarlet fever, erysipelas, rheumatic fever, pharyngitis, cellulitis)
    • Streptococcus agalactiae Lehmann and Neumann 1896 (Lancefield Group B; β-hemolytic) (sepsis of the newborn)
    • Streptococcus dysgalactiae group
      • S. dysgalactiae Diernhofer 1932
      • S. equi Sand and Jensen 1888 (includes S. equi zooepidemicus)
    • Streptococcus equinus Andrewes and Horder 1906 (aka S. bovis; γ-hemolytic)
    • Streptococcus canis Devriese et al. 1986
    • Streptococcus pneumoniae (Micrococcus pneumoniae Klein 1884) Chester 1901 (α-hemolytic); pneumococcal infection)
    • Streptococcus viridans group (α-hemolytic or non-hemolytic)
      • S. mitis Andrewes and Horder 1906
      • S. mutans Clarke 1924
      • S. oralis Bridge and Sneath 1982
      • S. sanguinis White and Niven 1946
      • S. sobrinus Coykendall 1974
      • Streptococcus milleri group (Lancefield Group F)
        • S. anginosus Andrewes and Horder 1906
        • S. constellatus (Diplococcus constellatus Prevot 1924) Holdeman & Moore 1974
        • S. intermedius Prevot 1925
  • family: Enterococcaceae
    • Enterococcus faecalis (Streptococcus faecalis Andrewes and Horder 1906 ) Schleifer & Kilpper-Bälz 1984 (γ-hemolytic)
    • Enterococcus faecium (Streptococcus faecium Orla-Jensen 1919) Schleifer & Kilpper-Bälz 1984 (γ-hemolytic; vancomycin-resistant enterococcus)

• order: Bacillales
  • family: Staphylococcaceae
    • Staphylococcus aureus Rosenbach 1884 (cellulitis, Staphylococcal scalded skin syndrome, toxic shock syndrome, food poisoning)
    • Staphylococcus epidermidis (Albococcus epidermidis Winslow & Winslow 1908) Evans 1916
    • Staphylococcus saprophyticus Fairbrother 1940 (urinary tract infection)
  • family: Bacillaceae
    • Bacillus anthracis Cohn 1872 (anthrax)
    • Bacillus cereus Frankland & Frankland 1887 (food poisoning)
  • family: Listeriaceae
    • Listeria monocytogenes (Bacterium monocytogenes Murray et al. 1926) Pirie 1940 (Listeriosis)

class: Clostridia

• order: Clostridiales
  • family: Clostridiaceae
    • Clostridium botulinum (Bacillus botulinus van Ermengem 1896) Bergey et al. 1923 (botulism)
    • Clostridium difficile (Bacillus difficilis Hall & O'Toole 1935) Prevot 1938 (pseudomembranous colitis)
    • Clostridium perfringens (Bacillus perfringens Veillon & Zuber 1898) Hauduroy et al. 1937 (gas gangrene, clostridial necrotizing enteritis)
    • Clostridium tetani (Bacillus tetani Flügge 1886) Bergey et al. 1923 (tetanus)
  • family: Peptostreptococcaceae
    • Peptostreptococcus sp.

class: Mollicutes

This group of eubacteria is characterized by the absence of a cell wall (aphragmabacteria). They was previously classified as Tenericutes, a sister group to Firmicutes, before being reassigned as a class within Firmicutes.

• order: Mycoplasmatales
  • family: Mycoplasmataceae
    • Mycoplasma genitalium Tully et al., 1983
    • Mycoplasma pneumoniae Somerson et al., 1963 (mycoplasmal pneumonia, primary atypical pneumonia)
    • Ureaplasma urealyticum Shepard et al., 1974 (Ureaplasma infection, urethritis)
• order: Anaeroplasmatales (or Erysipelotrichales)
  • family: Erysipelotrichaceae
    • Erysipelothrix rhusiopathiae (Bacterium rhusiopathiae Migula 1900) Buchanan 1918 (erysipeloid)

Bacteroidetes

class: Bacteroidetes

• order: Bacteroidales
  • family: Bacteroidaceae
    • Bacteroides fragilis (Bacillus fragilis Veillon and Zuber 1898) Castellani and Chalmers 1919
  • family: Porphyromonadaceae
    • Tannerella forsythia (Bacteroides forsythus Tanner et al. 1986) Sakamoto et al. 2002
    • Porphyromonas gingivalis (Bacteroides gingivalis Coykendall et al. 1980) Shah and Collins 1988
  • family: Prevotellaceae
    • Prevotella intermedia (Bacteroides melaninogenicus intermedius Holdeman and Moore 1970) Shah and Collins 1990

class: Flavobacteria

• order: Flavobacteriaceae
  • family: Flavobacteriales
    • Capnocytophaga canimorsus Brenner et al. 1990

Chlamydiae

• order: Chlamydiales
  • family: Chlamydiaceae
    • Chlamydia trachomatis (Rickettsia trachomae Busacca 1935) Rake 1957 (lymphogranuloma venereum, trachoma)
    • Chlamydophila psittaci (Rickettsia psittaci Lillie 1930) Everett et al. 1999 (psittacosis)
    • Chlamydophila pneumoniae (Chlamydia pneumoniae Grayston et al. 1989) Everett et al. 1999

Fusobacteria

• order: Fusobacteriales
  • family: Fusobacteriaceae
    • Fusobacterium necrophorum (Bacillus necrophorus Flugge 1886) Moore and Holdeman 1969 (Lemierre's syndrome)
    • Fusobacterium nucleatum (Bacillus fusiformis Veillon and Zuber 1898) Knorr 1922
      • Fusobacterium nucleatum nucleatum Knorr 1922
      • Fusobacterium nucleatum polymorphum (Fusobacterium polymorphum Knorr 1922) Dzink et al. 1990
    • Streptobacillus moniliformis (Streptothrix muris ratti Schottmuller 1914) Levaditi et al. 1925 (Actinobacillus muris Wilson and Miles 1955; rat bite fever)

Proteobacteria

class: Alpha Proteobacteria

• order: Rickettsiales
  • family: Rickettsiaceae
    • Rickettsia - spotted fever group
      • Rickettsia rickettsii (Dermacentroxenus rickettsii Wolbach 1919) Brumpt 1922 (Rocky Mountain spotted fever)
      • Rickettsia conorii Brumpt 1932 (Boutonneuse fever)
      • Rickettsia akari Huebner et al. 1946 (rickettsialpox)
    • Rickettsia - typhus group
      • Rickettsia typhi (Dermacentroxenus typhi Wolbach and Todd 1920) Philip 1943 (murine typhus)
      • Rickettsia prowazekii da Rocha-Lima 1916 (epidemic typhus)
    • Orientia tsutsugamushi (Theileria tsutsugamushi Hayashi 1920) Tamura et al. 1995 (scrub typhus)
  • family: Anaplasmataceae (or Ehrlichiaceae) (Ehrlichiosis and Anaplasmosis)
    • Anaplasma phagocytophilum (Rickettsia phagocytophila ovis Foggie 1949) Dumler et al. 2001 (human granulocytic ehrlichiosis)
    • Ehrlichia chaffeensis Anderson et al. 1992 (human monocytic ehrlichiosis)
• order: Rhizobiales
  • family: Brucellaceae
    • Brucella abortus (Bacterium abortus Schmidt 1901) Meyer and Shaw 1920 (Brucellosis)
  • family: Bartonellaceae
    • Bartonella bacilliformis (Bartonia bacilliformis Strong et al. 1913) Strong et al. 1915 (Carrion's disease)
    • Bartonella henselae (Rochalimaea henselae Regnery et al. 1992) Brenner et al. 1993 (cat scratch fever; bacillary angiomatosis)
    • Bartonella quintana (Rickettsia quintana Schmincke 1917) Brenner et al. 1993 (trench fever; bacillary angiomatosis)

class: Beta Proteobacteria

• order: Neisseriales
  • family: Neisseriaceae
    • Neisseria meningitidis (Micrococcus meningitidis cerebrospinalis Albrecht & Ghon 1901) Murray 1929 (meningococcal disease, Waterhouse-Friderichsen syndrome)
    • Neisseria gonorrhoeae (Merismopedia gonorrhoeae Zopf 1885) Trevisan 1885 (gonorrhea)
    • Eikenella corrodens (Bacteroides corrodens Eiken 1958) Jackson and Goodman 1972
    • Kingella kingae (Moraxella kingii Henriksen and Bovre 1968) Henriksen and Bovre 1976

• order: Burkholderiales
  • family: Burkholderiaceae
    • Burkholderia pseudomallei group
      • B. pseudomallei (Bacillus pseudomallei Whitmore 1913) Yabuuchi et al. 1993 (aka Pseudomonas pseudomallei Haynes 1957; melioidosis)
      • B. mallei (Bacillus mallei Zopf 1885) Yabuuchi et al. 1993 (aka Pseudomonas mallei Redfearn et al. 1966; glanders)
    • Burkholderia cepacia complex
      • B. cepacia (Pseudomonas cepacia Burkholder 1950) Yabuuchi et al. 1993
      • B. vietnamiensis Gillis et al. 1995
      • B. multivorans Vandamme et al. 1997
      • B. stabilis Vandamme et al. 2000
      • B. ambifaria Coenye et al. 2001
      • B. anthina Vandamme et al. 2002
      • B. cenocepacia Vandamme et al. 2003
      • B. dolosa Vermis et al. 2004
      • B. pyrrocinia (Pseudomonas pyrrocinia Imanaka et al. 1965) Vandamme et al. 1997
  • family: Alcaligenaceae
    • Bordetella pertussis (Hemophilus pertussis Bergey et al. 1923) Moreno-López 1952 (pertussis or whooping cough)
    • Bordetella parapertussis (Bacillus parapertussis Eldering and Kendrick 1938) Moreno-López 1952 (parapertussis)

• order: Nitrosomonadales
  • family: Spirillaceae
    • Spirillum minus (Rat-bite fever)

class: Gamma Proteobacteria

• order: Enterobacteriales
  • family: Enterobacteriaceae
    • Enterobacter cloacae (Bacillus cloacae Jordan 1890) Hormaeche and Edwards 1960
    • Escherichia coli (Bacillus coli Migula 1895) Castellani and Chalmers 1919
    • Klebsiella granulomatis (Calymmatobacterium granulomatis Arago & Vianna 1913) Carter et al. 1999 (granuloma inguinale or donovanosis)
    • Klebsiella oxytoca (Bacillus oxytocus perniciosus Flügge 1886) Lautrop 1956
    • Klebsiella pneumoniae (Hyalococcus pneumoniae Schroeter 1886) Trevisan 1887 (rhinoscleroma, Klebsiella pneumonia)
    • Plesiomonas shigelloides (Pseudomonas shigelloides Bader 1954) Habs and Schubert 1962 (aka Aeromonas shigelloides Ewing et al. 1961)
    • Proteus mirabilis Hauser 1885
    • Proteus vulgaris Hauser 1885
    • Salmonella enterica (Bacillus cholerae-suis Smith 1894) Kauffmann & Edwards 1952 (typhoid fever, paratyphoid fever, Salmonellosis)
    • Serratia marcescens Bizio 1823 (Serratia infection)
    • Shigella dysenteriae (Bacillus dysentericus Shiga 1897) Castellani & Chalmers 1919 (Shigellosis, bacillary dysentery)
    • Shigella flexneri Castellani & Chalmers 1919 (Shigellosis, bacillary dysentery)
    • Shigella sonnei (Bacterium sonnei Levine 1920) Weldin 1927 (Shigellosis, bacillary dysentery)
    • Yersinia enterocolitica (Bacterium enterocoliticum Schleifstein & Coleman 1939) Frederiksen 1964
    • Yersinia pestis (Bacterium pestis Lehmann & Neumann, 1896) van Loghem 1944 (aka Pasteurella pestis Bergey et al. 1923; plague/bubonic plague)
    • Yersinia pseudotuberculosis (Bacillus pseudotuberkulosis Pfeiffer 1889) Smith & Thal 1965

• order: Cardiobacteriales
  • family: Cardiobacteriaceae
    • Cardiobacterium hominis Slotnick and Dougherty 1964

• order: Legionellales
  • family: Legionellaceae
    • Legionella pneumophila Brenner et al. 1979 (Legionellosis)
    • Legionella longbeachae McKinney et al. 1982 (Legionellosis)
  • family: Coxiellaceae
    • Coxiella burnetii (Rickettsia burneti Derrick 1939) Philip 1948 (Q fever)

• order: Pasteurellales
  • family: Pasteurellaceae
    • Haemophilus influenzae (Bacterium influenzae Lehmann & Neumann 1896) Winslow et al. 1917 (Haemophilus meningitis, Brazilian purpuric fever)
    • Haemophilus ducreyi (Bacillus ulceris cancrosi Kruse 1896) Bergey et al. 1923 (chancroid)
    • Pasteurella multocida (Bacterium multocidum Lehmann and Neumann 1899) Rosenbusch and Merchant 1939 (Pasteurellosis)
    • Actinobacillus ureae (Pasteurella ureae Jones 1962) Mutters et al. 1986 (Actinobacillosis)
    • Actinobacillus hominis Friis-Mller 1985 (Actinobacillosis)
    • Aggregatibacter actinomycetemcomitans (Bacterium actinomycetem comitans Klinger 1912) Norskov-Lauritsen and Kilian 2006 (aka Actinobacillus actinomycetemcomitans Topley and Wilson 1929)

• order: Pseudomonadales
  • family: Pseudomonadaceae
    • Pseudomonas aeruginosa (Bacterium aeruginosum Schröter 1872) Migula 1900 (Pseudomonas infection)
  • family: Moraxellaceae
    • Moraxella catarrhalis (Mikrokkokus catarrhalis Frosch and Kolle1896) Henriksen and Bovre 1968 (aka Branhamella catarrhalis Catlin 1970)
    • Acinetobacter baumannii Bouvet and Grimont 1986

• order: Thiotrichales
  • family: Francisellaceae
    • Francisella tularensis (Bacterium tularense McCoy and Chapin 1912) Dorofe'ev 1947 (tularemia)

• order: Vibrionales
  • family: Vibrionaceae
    • Vibrio cholerae Pacini 1854 (cholera)
    • Vibrio vulnificus (Beneckea vulnifica Reichelt et al. 1979) Farmer 1980
    • Vibrio parahaemolyticus (Pasteurella parahaemolytica Fujino et al. 1951) Sakazaki et al. 1963 (aka Beneckea parahaemolytica Baumann et al. 1971)

• order: Xanthomonadales
  • family: Xanthomonadaceae
    • Stenotrophomonas maltophilia (Pseudomonas maltophilia Hugh and Ryschenkow 1961) Palleroni & Bradbury 1993

class: Epsilon Proteobacteria

• order: Campylobacterales
  • family: Campylobacteraceae
    • Campylobacter jejuni (Vibrio jejuni Jones et al. 1931) Veron & Chatelain 1973 (Campylobacteriosis)
    • Campylobacter coli (Vibrio coli Doyle 1948) Veron and Chatelain 1973
    • Campylobacter lari (Campylobacter laridis Benjamin et al. 1983) Benjamin et al. 1984
    • Campylobacter fetus (Vibrio fetus Smith and Taylor 1919) Sebald and Veron 1963
  • family: Helicobacteraceae
    • Helicobacter pylori (Campylobacter pyloridis Marshall et al. 1985) Goodwin et al. 1989 (peptic ulcer)
    • Helicobacter cinaedi (Campylobacter cinaedi Totten et al. 1988) Vandamme et al. 1991
    • Helicobacter fennelliae (Campylobacter fennelliae Totten et al. 1988) Vandamme et al. 1991

Spirochaetes

• order: Spirochaetales
  • family: Spirochaetaceae
    • Treponema pallidum (Spirochaeta pallida Schaudinn and Hoffmann 1905) Schaudinn 1905
      • Treponema pallidum pallidum (syphilis)
      • Treponema pallidum endemicum (bejel)
      • Treponema pallidum pertenue (yaws)
    • Treponema carateum (pinta)
    • Treponema denticola (Spirochaete denticola Flugge 1886) Chan et al. 1993
    • Borrelia recurrentis (Spirochaete recurrentis Lebert 1874) Bergey et al. 1925 (relapsing fever)
    • Borrelia burgdorferi Johnson et al. 1984 (Lyme disease, erythema chronicum migrans, neuroborreliosis)
  • family: Leptospiraceae
    • Leptospira interrogans (Spirochaeta interrogans Stimson 1907) Wenyon 1926 (leptospirosis)

References

1. ↑ Woese CR, Kandler O, and Wheelis ML. "Towards a natural system of organisms: Proposal for the domains Archaea, Bacteria and Eucarya." Proc Natl Acad Sci, USA 87:4576-4579, 1990.