Flashcards in 11. Gram-positive Bacteria Deck (44)
3 genera of low %GC bacteria?
Staphylococcus, streptococcus, lactobacillus
3 genera of high %GC bacteria?
Propionibacteria, mycobacterium, streptomyces
What are endospores?
Spores that are EXTREMELY heat and chemical resistant; are found in SOME G+ bacteria
__________ is a phylum of bacteria that are the source of most antibiotics used in medicine today
Largest genus of Actinobacteria phylum?
Example of a high %GC G+ bacteria that does NOT contain spores?
Chracteristic of Corynebacterium diphtheriae infection?
What genus of phylum Actinobacteria forms symbiotic associations with plants? What does it do?
Helps plant fix N2 while it makes spores in the plant (aid in its own reproduction
2 low %GC genera that are medically important? What nutritional group do they belong to?
Staphylococcus and streptococcus
What 2 species of staph are part of normal skin flora?
S.aureus and S.epidermis
Habitat of Staphylococcus
Skin and mucous membranes of warm blooded animals
Shape of staph?
Do Staph/Strept form endospores?
6 problems cased by S.aureus?
What does MRSA stand for?
Drug that can treat MRSA?
Oral cavity and upper respiratory tract
3 groups of Streptococci clustered by their phenotype?
Pyogenic, oral, other
2 species of pyogenic strep?
2 species of oral strep?
Example of a "other" strep species?
What does pyogenic mean?
Which streptococci is NON-pathogenic and is thought to be a probiotic?
How are pyogenic streptococci distinguished?
By their ability to cause a pattern of RBC lysis => beta-hemolysis
Which species of streptococci causes strep thoroat/scarlet fever/necrotizing fasiitis?
Which species of streptococci cause alpha-hemolysis?
Which species of strep is part of normal flora in oral cavity and doesn't cause hemolysis?
Example of a G+ bacteria genera that produce endospores?
What is one way of destroying endospores?
Autoclaving (121degC, 15psi)
What triggers endospore formation?
Sporulation when conditions are not optimal (low nutrients, low H2O)
Opposite of sporulation?
Germination - production of vegetative cells (regular bacterial cells)
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
4 ways of describing endospore location?
Central, subterminal, terminal, swollen sporangium
What are endospores?
Metabolically dormant form of bacteria
How long can endospores last?
Which part of the endospore contains peptidoglycan that will form the wall of the vegetative cell that grows out of the spore?
Part of endospore that can occupy 1/2 the spore volume?
Part of endospore that contains many layers of proteins and confers resistance to chemicals?
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
Why is protein denaturation fine for endospores?
Can re-fold when spore germinates
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
Difference in shape between staph and strep?
Staph - grape-like clusters
Strep - pairs/chains of cocci
Difference between alpha and beta hemolysis on blood agar?
Alpha - dark green colonies
Beta - media around and under colonies becomes transparent