Microbiology Flashcards

1
Q

Describe the appearance of staphylococcus sp.

A

Gram positive cocci in clusters

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2
Q

What are the two main types of staphylococcus infections

A
Staph aureus (coagulase positive)
Coagulase negative staph (epidermidis, saprophyticus)
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3
Q

What colour does staph aureus appear in blood agar

A

golden

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4
Q

Describe the appearance of a positive test result for a coagulase positive organism

A

Lump forming at the bottom of the test tube - the plasma has clotted

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5
Q

Describe the appearance of gram positive streptococci

A

Chains rather than clusters

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6
Q

What antibiotic is used to treat staph aureus

A

flucloxacillin

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7
Q

What is different about staph aureus to all other staph species

A

produces enzymes such as coagulase (clots plasma)

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8
Q

How might staph epidermis cause infection

A

When it is associated with an implanted artificial material such as joints or heart valves or Catheters

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9
Q

What organism causes urinary tract infection in women of child-bearing age

A

Staph saprophyticus

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10
Q

Strep species are anaerobic. True or false

A

False - they are aerobic

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11
Q

How are streps classified

A

By haemolysis on blood agar

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12
Q

What are the 3 types of haemolysis

A

beta - complete haemolysis
alpha - partial haemolysis
gamma - no haemolysis

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13
Q

what are the 2 categories of beta haemolytic streptococci

A
group A (throat, severe sin infections)
group B (meningitis in neonates)
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14
Q

what are the 2 categories of alpha haemolytic strep

A

pneumoniae

viridans (commensals of mouth, throat, vagina)

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15
Q

where do none haemolytic strep cause infection

A

bowel

UTI

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16
Q

Give 5 ways that the skin acts as a defence against infection

A
Intact 
Dry surface 
sebum (inhibits bacterial growth)
competitive bacterial flora
concept of resident and transient flora
17
Q

Is Impetigo highly infection

A

Yes - kids need to be kept off school because of it

18
Q

What happens in Staphylococcal scalded skin syndrome

A

The baby has lost vast areas of the surface of the skin. The wounds become weepy and therefore the baby will become dehydrated. They are treated aggressively with antibiotics and often need IV fluids

19
Q

What diseases can Group A strep cause

A
Infected eczema
Impetigo
Cellulitis
Erysipelas
Necrotising fasciitis
20
Q

What is the treatment of choice for group A strep

A

penicillin

21
Q

What is the treatment of necrotising fasciitis

A

Immediate surgical debridement as well as antibiotics

This is a life threatening condition

22
Q

What are the presenting complaints of necrotising fasciitis

A

Extreme pain

Not much to see on the skin surface

23
Q

When is it appropriate to take swabs from a leg ulcer

A

Signs of cellulitis or infection are present

24
Q

What does tinea mean?

A

ringworm

25
Q

What is Tinea pedis more commonly known as

A

Athlete’s foot

26
Q

How does the body acquire a fungal infection

A

through soggy skin

27
Q

Where do fungal infections attack and infect

A

Keratinised tissues only (skin, hair and nails)

28
Q

How do fungal infections have a ring appearanec

A

The lesion grows outward and heals in the centre

29
Q

How are fungal infections (dermatophyte infections) diagnosed?

A

clinical appearance
Woods light
skin scrapings, nail clippings, hair

30
Q

How are dermatophyte infections treated

A

Clotrimazole cream or similar

Topical nail paint (amorolfine)

31
Q

Where does candida cause an infection

A
In skin folds where the area is warm and moist
Under the breasts 
groin areas
abdominal skin folds 
nappy area in babies
32
Q

What is the causative organism of scabies

A

Sarcoptes scabiei

33
Q

What is Norwegian Scabies

A

Chronic crusted form of Sarcoptes scabiei which is highly infection

34
Q

What is the treatment of scabies

A

Malathion lotion - applied overnight to the whole body and washed off the next day

35
Q

What is the treatment for lice

A

Malathion

36
Q

What 3 different types of patients require single room isolation

A

Patients with Group A strep infection
Patients with methicillin resistant Staph aureus (MRSA)
Patients with Scabies