Mosby's Micro/Path Bacteria Flashcards
Streptococcus are gram +. how do they use oxygen
facultative anaerobes (catalase/SOD/fermentation/respiration)
What is the hemolytic classification for streptococcus
both alpha and beta hemolytic kinds
- ___ hemolytic means incomplete lysis of red blood cells = appears in __ zone
- ___ hemolytic means complete lysis of red blood cells = appears in __ zone
- __ hemolytic - do NOT lyse red blood cells
- alpha = green zone
- beta = complete = clear
- gamma
S. viridans, S. mutans, S. sanguis, S. salivarius are alpha or beta hemolytic
alpha (green)
the bacteria that cause SUBACUTE ENDOCARDITIS
ALPHA hemolytic strep: ex Strep viridans, s. sanguis, s.mutans, s.salivarius
Beta hemolytic streptococcus are further divided into the Lancefield groups _-__
A thru U
Beta hemolytic bacteria include Strep
pyogenes
Alpha/beta/gamma hemolytic strep:
Strep viridans
alpha -subacute endocarditis
Alpha/beta/gamma hemolytic strep:
strep mutans
Alpha-
Alpha/beta/gamma hemolytic strep:
strep salivarius
alpha-
incomplete lysis green
Alpha/beta/gamma hemolytic strep:
strep sanguis
alpha -
Alpha/beta/gamma hemolytic strep:
strep pyogenes
beta (complete lysis = clear)
which strep has a virulence factor M protein
strep pyogenes Beta hemolytic (clear, complete lysis)
Lipid A found on
LPS
M protein found on
strep pyogenes
Strep pyogenes mneumonic?
B - SMASHEED (virulence factors) NIPPLESS G (diseases)
B = beta hemolytic
1.Streptolysins O/S: hemolysin causes lysis of red and white blood cells
2. M protein
3. Anti-C5a peptidase
4. Streptokinase (fibrinolysin) - dissolves fibrin (blood clots) by cleaving plasminogen = increase levels of plasmin.
5. Hyaluronidase = spreading factor that breaks down hyaluronic acid, bacteria can spread easier
6. Exotoxin A- causes necrotizing fasciitis by destroying tissue
6. Erythrogenic toxin -scarlet fever rash
7. DNA-se cleave DNA
strep pygogenes diseases?
NIPPLESS G Necrotizing fasciitis and myositis imptetigo pharyngitis (strep throat) pneumonia lymphangitis erysipelas and cellulits scarlet fever/rheumatic fever strep TSS Glomerulonephritis
The rash is the most striking sign of ___. It usually begins looking like a bad sunburn with tiny bumps and it may itch. The rash usually appears first on the neck and face, often leaving a clear unaffected area around the mouth. It spreads to the chest and back, then to the rest of the body. In body creases, especially around the underarms and elbows, the rash forms classic red streaks. Areas of rash usually turn white when you press on them. By the sixth day of the infection the rash usually fades, but the affected skin may begin to peel.
scarlet fever = strep = is an infectious disease which most commonly affects 4–8-year-old children
strawberry tongue =
scarlet fever
This strep is an alpha hemolytic (incomplete lysis = green) and causes endocarditis and caries
Strep viridans
Strep pneumoniae
- hemolytic class
- virulent factors
- diseases it causes
- alpha = A in the mneumonic
- polysac Capsule (prevent phagocytosis)
Pneumolysin = cytolytic toxin
IgA protease- hydrolyzes IgA to aid colonization in respiratory mucosa - pneumonia = the most common cause of bacterial pneumonia
meningitis
otitis media - the most common cause in infants older than 2 months (ear infection)
Strep Pneumoniae “A PIC MOP”
Strep Pyogenes =
Strep Pneumoniae =
Staph Aureus -
MNEMONICS
Strep Pyogenes = B SMASHEED NIPPLESS G
Strep Pneumoniae = A PIC MOP
Staph Aureus - SOFT PAINS (disease it causes) B PAC SHEET
__ are the most common bacteria in the mouth
Streptococci
Strep are cariogenic bacteria because they
- lower the pH by producing ___ = promote demineralization of enamel which begins b/w what pH?
- they provide a structural component for plaque by producing ___.
- pH 1-5 by producing lactic acid
2. dextrans
strep surfaces contain what enzyme that sucrose to from glucose (dextrans) and fructose/fructans?
glucosyl transferase
strep provide food for bacterial growth by their production of
fructans (levans) from fructose
which strep is the most cariogenic
why?
strep mutans
b/c it has a polysaccharide glycocalyx coating that allows it to stick to surfaces
- ___ Strep is the most commonly found in the mouth
2. _____ strep is the most cariogenic
- strep sanguis
2. strep mutans
___ are commonly present in Ludwig’s angina
streptococcus
staphylococcus aureus is gram + grape like clusters that are a part of our __ flora
skin and mucous membrane flora
Staph aureus causes suppurative or ___ forming infections mostly in the form of
pus forming, abscesses
Virulence factors of staph aureus
B PaC SHEET
B-lactaminase (penicillinase, Beta hemolysin)
Protein A- in cell wall. inhibits complement fixation by binding to the Fc portion of IgG - decreased phagocytosis and opsonization. Can also elicit hypersensitivity rxn = damage platelets
Coagulase = clots blood (s. aureus)
staphylokinase (fibrinolysin) dissolves blood clots by cleaving plasminogen to increase levels of plasmin
hyaluronidase
enterotoxin - food poisoning (diarrhea, vomiting)
exfoliatin - causes scaled skin syndrome = exfoliative dermatitis in children
toxic shock syndrome toxin
