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50 terms

Microbiology: Chapter 11

Exam 2: Bacteria types
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Proteobacteria
most of the gram-negative, chemoheterotrophic bacteria, presumed to come from common photosynthetic ancestor, name comes from Greek god Proteus who could assume many shapes
Alphaproteobacteria
most are capable of growth at very low levels of nutrients, unusual morphology: protrusions such as stalks and buds called prosthecae, agriculturally important due to nitrogen fixation in symbiosis with plants, plant and animal pathogens
Rickettsia
Alphaproteobacteria
Obligate intracellular parasites: reproduce only within a mammalian cell, gram-negative, rod-shaped, transmitted to humans through bites of insects and ticks
Damage permeability of human capillaries: cause rashes
Rickettsia prowazekii
epidemic typhus from lice
Rickettsia typhi
endemic murine typhus from rat fleas
Rickettsia rickettsii
Rocky mountain spotted fever from ticks
Rhizobia
Alphaproteobacteria
Includes Rhizobium and Bradyrhizobium
Infect the roots of leguminous plants (beans, peas, or clover)
Formation of nodules on the plant
Symbiotic relationship: bacteria fixes nitrogen from air for plant to use
Agrobacteria
Alphaproteobacteria
ability to invade plants
No nitrogen fixation, does not invade roots
Agrobacterium temfaciens
Causes crown gall in plants where roots and stem merge
inserts a plasmid that contains genetic information into the plant's chromosomal DNA
Betaproteobacteria
Use nutrient substances that diffuse away from areas of anaerobic decomposition of organic matter: hydrogen gas, ammonia, and methane
Several pathogenic bacteria
Spirillum
Betaproteobacteria
Mainly in fresh water
motile by conventional polar flagella
Relatively large, gram-negative, aerobic bacteria
Burkholderia
Betaproteobacteria
motile by a single polar flagellum or tuft of flagella
Burkholderia cepacia
Best known species of burkholderia
aerobic, gram-negative rod
Large nutritional spectrum and can degrade over 100 organic molecules
Contamination of equipment and drugs in hospitals
Can grow in disinfectant solutions
Metabolizes secretions in patients with cystic fibrosis
Bordetella
Betaproteobacteria
Bordetella pertussis
nonmotile, aerobic, gram-negative rod
Cause of whopping cough or pertussis
Neisseria
Betaproteobacteria
aerobic, gram-negative cocci
Inhabit mucous membranes of mammals
Neisseria gonorrhoeae
Causes gonorrhea
Neisseria meningitidis
Causes meningococcal meningitis
Gammaproteobacteria
Largest subgroup of proetobacteria
Pseudomonas
Gammaproteobacteria
Pseudomonadales
Aerobic, gram-negative rods
Motile by polar flagella: single or tufts
Many excrete extracellular, water-soluble pigments that diffuse into their media
Can grow on minute traces of carbon sources such as soap residue and cap-liner adhesives
People with cystic fibrosis are susceptible
Have as much genetic capacity as the eukaryotic yeasts and half as the fruit fly
Pseudomonas aeruginosa
Pseudomonadales
Can cause infection of the urinary tract, burns, and wounds, and can cause blood infections
Azotobacter
Gammaproteobacteria
Pseudomonadales
Nitrogen fixing bacteria
Free living in soil
Large, heavily capsulated
Azomonas
Gammaproteobacteria
Pseudomonadales
Nitrogen fixing bacteria
Free living in soil
Large, heavily capsulated
Legionellales
Gammaproteobacteria
Previously considered rickettsial
Readily grow on suitable artificial media
Legionella
Gammaproteobacteria
Legionellales
Cause of an outbreak of pneumonia
Common in streams
Colonize habitats such as warm-water supply lines in hospitals and water in the cooling towers of air conditioning systems
Coxiella
Gammaproteobacteria
Legionellales
Coxiella burnetii: responsible for Q fever
Need a mammalian host to reproduce
Not transmitted through insect or tick bites
Most commonly transmitted through aerosols or contaminated milk
High resistance to the stresses of airborne transmission and heat transmission
Vibrio
Gammaproteobacteria
Legionellales
Slightly curved rods
Usually inhabit coastal salt waters
Transmitted usually by raw or undercooked fish
Vibrio cholerae
Gammaproteobacteria
Legionellales
Causes cholera
Enterobacteriales
Gammaproteobacteria
Facultatively anaerobic, gram-negative rods
Peritrichously flagellated if motile
Inhabit the intestinal tracts of humans and other animals
Fimbriae that help them to adhere to surfaces or mucous membranes
Sex pili for reproduction: help to transfer bacteria resistance
Produce bacteriocins that cause the lysis of related bacteria, which may help maintain the ecological balance in the intestines
Enterics
Another word used to reference the bacterial group Enterobacteriales
Intestinal tracts
Escherichia
Gammaproteobacteria
Enterobacteriales
Escherichia coli: most common inhabitants in human intestinal tract, also very useful in the laboratory
Salmonella
Gammaproteobacteria
Enterobacteriales
Almost all are potentially pathogenic
Common inhabitants of the intestinal tract
Often divided into several serovars/serotypes: serological varieties
Shigella
Gammaproteobacteria
Enterobacteriales
Responsible for bacillary dysentery or shigellosis
Found only in humans
Some cause life-thretening dyssentery
Klebsiella
Gammaproteobacteria
Enterobacteriales
Commonly found in soil or water
Fix nitrogen from the atmosphere which could be a nutritional advantage
Causes a serious form of pneumonia in humans
Serratia
Gammaproteobacteria
Enterobacteriales
Production of red pigment
Probably the cause of many urinary and respiratory infections in hospitals
Proteus
Gammaproteobacteria
Enterobacteriales
Swarming type of growth
swarmer cells have flagella ,move to outside of colony, then resort to normal growth
In urinary tract and wounds
Yersinia
Gammaproteobacteria
Enterobacteriales
Yersinia pestis: causes plague, Black death in Europe
Fleas transmit the disease
Erwinia
Gammaproteobacteria
Enterobacteriales
Primarily plant pathogens
Produce enzymes the hydrolyze the pectin between plant cells that causes plant cells to separate: plant rot
Enterobacter
Gammaproteobacteria
Enterobacteriales
Cause urinary tract infections
widely distributed in humans and animals and water, sewage, and soil
Pasteurellales
Gammaproteobacteria
Non motile
Best known as human and animal pathogens
Haemophilus
Gammaproteobacteria
Pasteurellales
X factor: heme fraction: need blood for respiration
V factor: NAD+ or NADP+: cofactor also needed from media for respiration
Deltaproteobacteria
Include some bacteria that are predators on other bacteria
Bdellovibrio
Deltaproteobacteria
attacks other gram-negative bacteria
Attaches tightly and reproduces in the periplasma
Cell elongates and the cell lyses releasing the bacteria
Desulfovibrionales
Deltaproteobacteria
Sulfur reducing bacteria
Use oxidized forms of sulfur instead of oxygen
Epsilonproteobacteria
slender, gram-negative rods
Helical or curved
Campylobacter
Epsilonproteobacteria
Each cell has one polar flagellum
Can cause spontaneous abortion
Leading cause of outbreaks of foodborne intestinal disease
Helicobacter
Epsilonproteobacteria
Microaerophilic curved rods with multiple flagella
Cause peptic ulcers in humans
Two groups of Gram-positive bacteria
Firmicutes (low G + C ratios)
Actinobacteria (high G + C ratios)
Firmicutes
Low G + C ratio
Includes important endospore-forming bacteria
Mycoplasma also found in this phylum, although they do not have a cell wall
Clostridium
Firmicutes
Clostridiales
Obligate anaerobes
Rod-shaped cells
Contain endospores that usually distend the cell
Endospore: resistant to heat and many chemicals