Staph & Strep Flashcards

1
Q

What does the catalase test detect the presence of?

A

Catalase enzyme in aerobic organisms

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2
Q

What can the catalase test differentiate?

A

Staphylococci from streptococci and helps to confirm gram stain observations

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3
Q

What are the two recognised stphylococci used of medical importance?

A

Staphylococcus aureus
Staphylococcus epidermidis

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4
Q

Are staphylococci pathogenic?

A

Not always they are a normal part of the flora of URTI and skin

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5
Q

how to differentiate the two staphylococci?

A

A diagnosis on manitol salts agar
S.aureus ferments mannitol, creating acid, changing pH, changes from yellow to red

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6
Q

How is S. aureus disease transmitted?

A

Touch from an infected but asymptomatic person to a susceptible individual
Also from contaminated food

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7
Q

What is S. aureus caused by?

A

Acne, boils, pimples, pneumonia, carditic, meningitis

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8
Q

Are most staphylococcal infections pus forming?

A

Yes

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9
Q

Is alpha toxin hemolysin from S. aureus pore forming?

A

Yes

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10
Q

What does hemolysin do when infected?

A

Lyses red blood cells by inserting into their membrane and forming a hole
Host cell contents leak

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11
Q

What does S. aureus produce?

A

Coagulase, a tissue destroying enzyme

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12
Q

What is the coagulase test?

A

Test to see if an organism converts fibrin to fibrinogen

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13
Q

What is S. aureus leucocidin?

A

Another toxin that seperates the components that cats together to damage membranes

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14
Q

What does S. aureus leucocidin target?

A

White bloods cells
Attcking against the immune system

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15
Q

What is toxic shock syndrome?

A

A complication of S . aureus infection

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16
Q

What are the symptoms of toxic shock?

A

High fever
Rash
Vomiting
Diarroea
Death

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17
Q

What is the cause of toxic shock?

A

The use of highly absobant tampons

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18
Q

What is a treatment of S. aureus?

A

Penicillin and cephalosporin

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19
Q

How do the treatments work?

A

Inhibit bacterial cell wall biosynthesis and prevent cross-linking in the peptidoglycan layer

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20
Q

What is beta-lactamases?

A

Enzymes produced by bacteria
(mechanism of resistance)

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21
Q

What does MRSA stand for?

A

Methicillin resistant staphylococcus aureus

22
Q

What is MRSA?

A

Infections that are resistant to many drugs

23
Q

How to prevent S. aureus infection?

A

Imposible to prevent
People carry it without knowing
Good hygiene
Avoiding contact
Keeping wounds covered

24
Q

What distance is the best fro pathogens to trnasmit?

A

Short distances

25
Does stretococci and staphylococcus areus have a thin ot thick cell and does it dry easily?
They have thich cell walls and are more resistant to drying
26
What are the symptoms of URTI?
Common cold Annoying but not life threatning
27
What are the symptoms of LRTI?
problematic Bacterial / pneumonia Big issue for the immunocompromised or elderly
28
What does URTI stand for?
Upper respiratory tract infection
29
Is URTI streptococci gram positive and what is the shape?
Gram positive and spherical bacteria in chains not clusters
30
What does streptococci commonly cause?
Strep throat
31
How can streptococcus be differentiated from staphylococcus?
Gram stain arrangement Catalase test Blood agar homolysis
32
What can stretococci also produce?
Homolysins
33
What are homolysins?
Lysis of red blood cells
34
What are the types of hemolysis?
Alpha Beta Gamma
35
What is alpha haemolysis?
Partial or green haemolysis
36
What is beta haemolysis?
Complete lysis of red blood cells
37
What is gamma haemolysis?
Not showing typical alpha or beta haemolysis
38
What is strep throat?
A bacterial infection of the throat, inflammation and pain, severe sore throat
39
What do S. pyogenes produce in strep throat?
Hemolysin Lyses red blood cells which cause beta-hemolysis on blood agr pkates
40
What are the symptoms of strep throat?
Enlarged tonsils Red spots on the palate Mild fever Generally feeling unwell Tender lymph nodes
41
What are some treatments of strep throat?
Antibiotics
42
How to diagnose strep throat?
Rapid antigen detection systems Culture in a blood agar plate
43
What is scarlet fever?
Exotoxins from streptococcus acts as superantigens, causing host inflammation and tissue destruction
44
What are the symptoms of scarlet fever?
A body wide infection Severe sore throat Fever Characteristic rash
45
How is scarlet fever treated?
Antibiotics or can get better on its own
46
What are the complications to strep throat?
Rheumatic fever
47
Why is rheumatic fever bad?
The immune response to streptococcus infection can generate antibodies that cross react with human cells
48
What are the symptoms of rheumatic fever?
Fever Painful and tender joints Red, hot or swollen joints Small, painess bumps beneath the skin Chest pain Heart murmur Fatigue Outbursts of unusual behaviour
49
What is streptococcus pneumoniae?
An invasive lung disease
50
What does streptococcus pneumoniae do?
When the aveoli, an inflammatory response is stimulated causing plasma, blood and white blood cells to fill the alveoli