staph Flashcards
staphylococcus genus are
gram-positive cocci
how long can Staphylococcus survive at 60 degree
about a half-hour
how long can Staphylococcus survive at 4 degrees
months
3 importantS Staphylococcus species
- Staphylococcus aureus
- Staphylococcus epidermidis
- Staphylococcus saprophyticus
each of the important species of staph are
normal flora, disease occured when misplaced or when a bad strain is aqquired
hemolysis S. aureus
Beta
hemolysis S. epidermidis
Gamma
hemolysis S. saprophyticus
Gamma
coagulas S. aureus
positive
coagulase S. epidermidis
negative
coagulase S. saprophyticus
negative
color S. aureus
gold/yellow
color S. epidermidis
white
color S. saprophyticus
white/yellow
novobiocin
antibiotic
is S. aureus resistant to novbiocin
no
is S. epidermidis resitant to novobiocin
no
is S. saprophyticus resistant to novobiocin
yes
novobiocin
is an antibiotic
in human blood, what waits for a signal to come from damaged tissue
prothrombin
when prothrombin gets a signal from damaged tissue… it is converted to
thrombin
what does thrombin do
convert fibrinogen into fibrin
what does fibrin do
weaves into a mesh, an integral part of clot formation
who secretes coagulase
S. aureus (few other non-staph bacteria)
when S. aureus and (few other non-staph bacteria) secrete coagulase
it mimics the damaged signal, but instead causes prothrombin to be converted into a special form
when when S. aureus and (few other non-staph bacteria) secrete coagulase it causes prothrombin to be converted into what special form
staphylothrombin
staphylothrombin function
converts fibrinogen to fibrin that coats the staph bacteria, protecting it from the immune system
in phagocytosis, dendritic cells and macrophages
hold out digested guts (antigens) for other immune cells to see
dendritic cells and macrophages holding out macrophages is a
delicate process- only a small subset of T cells actually res
why is dendritic cells and macrophages holding out macrophages is a delicate process
- only a small subset of T cells actually respond to an antigen, even if bad
what percentage of T cells actually respond to an antigen
0.001 %
superantigens are different than normal antigens because
they stimulate a large amount of T cells in an area
what percentage of T cells do superantigens stimulate
20% or more
superantigens stimulating a large amount of T cells is called
polyclonal T cell activation
polyclonal T cell activation leads to
excessive cytokine release
excessive cytokine release of polyclonal T cell activation can lead to
fatal shock or organ failure
some strains of what create a superantigen
S. aureus
superantigen created by strains of S. aureus
SEB
SEB
Staphylococcal enterotoxin B
another word for SEB, depending on wher it acts
TSST
TSST
toxic shock syndrome toxin
TSST / SEB is
a single protein created by 30-50% of strains of S. aureus
if an SEB-secreting strain of S. aureus makes is way to _____
to intestines, the superantigen causes widespread inflammation
result of SEB-secreting strain of S. aureus in intestines
- projectile vomiting
- abdominal pain
- sometimes diarrhea
S. aureus and its superantigen iin the intestines are a type of
food poisoning that is rapid onset
how long after eating food w/ S. aureus do you show symptoms of food poisoning
1-6 hours
is staph the only caue of food poisoning
no, but is a common one
other staph associated enterotoxins :
SEA - SEE, SEE - SEI, and SER - SET have been named
which is the only staph-associated superantigen
SEB
first example of S. aureus and its superantigen
Laredo TX, 1968
Laredo TX, 1968
1364 elementary school children fell ill, chicken salad off-sit, not refrigerated, shipped to district
example 2 of S. aureus and its superantigen
Spring 1989» canned mushrooms
when SEB enters the blood stream
leads to toxic shock syndrome
toxic shock syndrome primarily associated with what 3 things
- extended use of hyperabsorbent tampons
- cosmetic surgeries
- uncleaned abrasions(rare)
what cosmetic surgeries usually lead to toxic shock syndrome
material packed into the nose
in each case of toxic shcok syndrome
S. aureus secretes SEB/TSS into the bloodstream
the result of of toxic syndrome is
bad.. defined by 5 plus of characteristics
what characteristics does toxic shock syndrome show - First 3
- body temperature over 102 degrees F
- blood pressure below 90 mmHg
- Macular Erythroderma
what characteristics does toxic shock syndrome show - Second 3 `
- desquamation
- involvement/failure of at least organ systems
- no positive blood results for other likely suspects
desquamation during toxic shock syndrome is
within 7-14 days, especially on palms and soles of feet
Macular Erythrodema
sunburn appearance
in adition to carrying superantigens, certain strains of S. aureus can carry
exfoliatins
what two exfoliatins can S. aureus carry
exfoliative toxin A and exfoliative toxin B
each of the exfoliative toxins targets
targets and cleaves protein dsg-1
dsg-1
desmoglein-1
where is desmoglein-1 found
only in the desmosomes of human skin
desmosomes
structure that holds cells together
staph (S. aureus) is more commonly the cause of
pyogenic infections
pyogenic infections
buildups of pus to fight the bacteria.
pus usually comes….
as a byproduct of the war between phagocytes and pathogens: the phagocytes eat so much that they eventually “pop”.
what makes more pus
bacteria also secrete substances to kill phagocytes before they start eating
forms that pus buildup can take
- Impetigo
- Folliculitis
- Carbuncle
- Furuncle
Impetigo
superficial infection
Folliculitis
infection of hair follicle
Carbuncle
abscess
Furuncle
boil
treatment of staph infections;
antibiotics , but staph infections evolving to counteract
MRSA
Methicillin-resistant Staphylococcus aureus
MRSA actually
resists many different types of antibiotics not just methicillin
now in order to treat MRSA doctors
give stronger antibiotic vancomyscin
in other regions where vancomycin was the first choice antibiotic
VRSA emerged
VRSA
vancomycin-resistant S. aureus
from horizontal gene transfer of S. aureus there is now
MVRSA»_space;> SUPERBUG
S. epidermidis is
not very scary, not have many virulence factors like S. aureus
scary feature of S. epidermidis
form biofilms on plastic surfaces
S. epidermidis forming biofilms on plastic surfaces
make it incredibly difficult for antibiotics to penetrate
the result of a biofilm forming is often
follow-up surgery to remove the plastic
biofilms of S. epidermidis often form on
- catheters
- replacement heart valves
- prosthetic joints
biofilms forming on catheters
response for over 50% of catheter infections
biofilms forming on replacement heart valves
leads to endocarditis
endocarditis
inflammation of heart inner lining
what staph species sometimes occupies the normal flora of the body
S. saprophyticus
when S. saprophyticus gets inside the urinary tract of a woman
(usually through sex) causes a urinary tract infection
symptoms of urinary tract infection
- burning sensation while urinating
- need to urinate often
- cloudy urine
urinary tract infections usually onsets
24-48 hours after sexual activity
urinary tract infections are often called
honeymoon cystitis
the proteins are degraded by exfoliative toxins are
in the junction between the stratum granulosum and the stratum spinosum of the epidermis
degradation of desmosomes between the stratum granulosum and the stratum spinosum leads to what
SSSS
SSSS
Staphylococcal scalded skin syndrome
symptoms of SSSS
skin blisters within 24-48 hours of onset, common in young children
