| Bacterial Type |
Characteristics |
|
Acetic acid bacteria
|
Mostly rod-shaped, gram-negative,
aerobic; highly tolerant
of acidic conditions; generate organic acids |
|
Actinomycete (mostly) |
Rod-shaped or filamentous, GRAM-POSITIVE,
aerobic; common in soils;
essential to growth of many plants; source of much of original antibiotic
production in pharmaceutical industry |
|
Coccoid (mostly) |
Spherical, sometimes in clusters or strings,
GRAM-POSITIVE,
aerobic and
anaerobic; resistant to
drying and high-salt conditions; Staphylococcus species common on human
skin, certain strains associated with toxic shock syndrome |
|
Coryneform |
Rod-shaped, form club or V shapes,
GRAM-POSITIVE,aerobic;
found in wide variety of habitats, particularly soils; highly resistant
to drying; include Arthrobacter, among most common forms of life on
earth |
|
Endospore-forming (mostly) |
Usually rod-shaped, can be GRAM-POSITIVE or
gram-negative; have highly
adaptable, heat-resistant spores that can go dormant for long periods,
possibly thousands of years; include
CLOSTRIDIUM
and
BACILLUS
|
|
Enteric(mostly) |
Rod-shaped, gram-negative,
aerobic but can live in certain
anaerobic conditions; produce
nitrite from nitrate, acids from glucose; include Escherichia coli,Salmonella
(over 1000 types), and Shigella |
|
Gliding(mostly) |
Rod-shaped, gram-negative,
mostly aerobic; glide on
secreted slimy substances; form colonies, frequently with complex fruiting
structures |
|
LACTIC
ACID (mostly) |
Rod-shaped or cocci, GRAM-POSITIVE,
facultative anaerobic
or microaerophilic; produce
lactic acid through fermentation; include:
LACTOBACILLUS, essential in dairy product formation, and
STREPTOCOCCUS
(common in humans),
BIFIDOBACTERIA
; Catalase negative |
|
Mycobacterium |
Pleomorphic, spherical or rod-shaped, frequently branching, no gram
stain, aerobic; commonly
form yellow pigments; include Mycobacterium tuberculosis, cause of tuberculosis |
|
Mycoplasma |
Spherical, commonly forming branching chains, no gram stain,
aerobic but can live in certain
anaerobic conditions; without cell walls yet structurally resistant
to lysis; among smallest of bacteria; named for superficial resemblance
to fungal hyphae (myco- means 'fungus') |
|
Nitrogen-fixing |
Rod-shaped, gram-negative, aerobic;
convert atmospheric nitrogen gas to ammonium in soil; include Azotobacter,
a common genus |
|
Propionic acid |
Rod-shaped, pleomorphic, GRAM-POSITIVE,anaerobic;
ferment lactic acid; fermentation produces holes in Swiss cheese from
the production of carbon dioxide |
|
Pseudomonad |
Rod-shaped (straight or curved) with polar flagella, gram-negative,
aerobic; can use up to 100
different compounds for carbon and energy |
|
Rickettsia |
Spherical or rod-shaped, gram-negative, aerobic; cause Rocky Mountain spotted fever and typhus; closely related to Agrobacterium, a common gall-causing plant bacterium
|
|
Sheathed |
Filamentous, gram-negative,aerobic;
'swarmer' (colonizing) cells form and break out of a sheath; sometimes
coated with metals from environment |
|
Spirillum(mostly) |
Spiral-shaped, gram-negative,aerobic; include Bdellovibrio, predatory
on other bacteria |
|
Spirochete(mostly) |
Spiral-shaped, gram-negative,mostly
anaerobic; common in moist environments, from mammalian gums
to coastal mudflats; complex internal structures convey rapid movement;
include Treponemapallidum
(cause of syphilis) |
Sulfate- and
Sulfur-reducing |
Commonly rod-shaped, mostly gram-negative,
anaerobic; include Desulfovibrio,
ecologically important in marshes |
Sulfur- and
iron-oxidizing |
Commonly rod-shaped, frequently with polar flagella,
gram-negative,mostly
anaerobic; most live in neutral (nonacidic) environment |
|
Vibrio(mostly) |
Rod- or comma-shaped, gram-negative,aerobic; commonly with a single
flagellum; include
Vibrio cholerae
(cause of cholera), and luminescent forms symbiotic with deep-water
fishes and squids |
