Flashcards in 11. Gram-positive Bacteria Deck (44)
1
3 genera of low %GC bacteria?
Staphylococcus, streptococcus, lactobacillus
2
3 genera of high %GC bacteria?
Propionibacteria, mycobacterium, streptomyces
3
What are endospores?
Spores that are EXTREMELY heat and chemical resistant; are found in SOME G+ bacteria
4
__________ is a phylum of bacteria that are the source of most antibiotics used in medicine today
Actinobacteria
5
Largest genus of Actinobacteria phylum?
Streptomyces
6
Example of a high %GC G+ bacteria that does NOT contain spores?
Corynebacterium diphtheriae
7
Chracteristic of Corynebacterium diphtheriae infection?
Swollen neck
8
What genus of phylum Actinobacteria forms symbiotic associations with plants? What does it do?
Frankia
Helps plant fix N2 while it makes spores in the plant (aid in its own reproduction
9
2 low %GC genera that are medically important? What nutritional group do they belong to?
Staphylococcus and streptococcus
Chemoorganoheterotrophs
10
What 2 species of staph are part of normal skin flora?
S.aureus and S.epidermis
11
Habitat of Staphylococcus
Skin and mucous membranes of warm blooded animals
12
Shape of staph?
Grape-like cluseters
13
Do Staph/Strept form endospores?
No
14
6 problems cased by S.aureus?
Boils
Abscesses
Impetigo
Food poisoning
Blood infections
Pneumonia
15
What does MRSA stand for?
Methicillin-resistant S.aureus
16
Drug that can treat MRSA?
Vancomycin
17
Habitatof Streptococcus?
Oral cavity and upper respiratory tract
18
3 groups of Streptococci clustered by their phenotype?
Pyogenic, oral, other
19
2 species of pyogenic strep?
S.pyogenes, S.agalactiae
20
2 species of oral strep?
S.mutans, S.gordonii
21
Example of a "other" strep species?
S.thermophilus
22
What does pyogenic mean?
Pus-forming
23
Which streptococci is NON-pathogenic and is thought to be a probiotic?
S. thermophilus
24
How are pyogenic streptococci distinguished?
By their ability to cause a pattern of RBC lysis => beta-hemolysis
25
Which species of streptococci causes strep thoroat/scarlet fever/necrotizing fasiitis?
S.pyogenes
26
Which species of streptococci cause alpha-hemolysis?
S.pneumoniae
27
Which species of strep is part of normal flora in oral cavity and doesn't cause hemolysis?
S.mutans
28
Example of a G+ bacteria genera that produce endospores?
Clostridium
29
What is one way of destroying endospores?
Autoclaving (121degC, 15psi)
30
What triggers endospore formation?
Sporulation when conditions are not optimal (low nutrients, low H2O)
31
Opposite of sporulation?
Germination - production of vegetative cells (regular bacterial cells)
32
2 ways to detect presence of endospores?
Directly - special stains
Indirectly - boil sample for 10 mins, leave at room temp for 24 hrs => if you see germination, had endospores
33
4 ways of describing endospore location?
Central, subterminal, terminal, swollen sporangium
34
What are endospores?
Metabolically dormant form of bacteria
35
How long can endospores last?
~100,000 years
36
Which part of the endospore contains peptidoglycan that will form the wall of the vegetative cell that grows out of the spore?
Core wall
37
Part of endospore that can occupy 1/2 the spore volume?
Cortex
38
Part of endospore that contains many layers of proteins and confers resistance to chemicals?
Spore coat
39
Describe 3 ways the spore components enable the spore to survive extreme conditions?
Spore coat - protects from chemicals/lytic enzymes
Inner membrane - impermeable to many chemicals, including those that cause DNA damage
Core - very low water content. slightly lower pH, dipicolnic acid
40
Why is protein denaturation fine for endospores?
Can re-fold when spore germinates
41
What does dipicolinic acid do? Where is it found?
Complex with calcium ions, inserts into nitrogen bases of DNA to stabilize them
Found in core of endospore
42
Difference in shape between staph and strep?
Staph - grape-like clusters
Strep - pairs/chains of cocci
43
Difference between alpha and beta hemolysis on blood agar?
Alpha - dark green colonies
Beta - media around and under colonies becomes transparent
44