Bacteria, fungi and yeast of skin (part 1) Flashcards
1
Q
What are the chemical and mechanical defenses of the skin?
A
- mechanical - keratinocytes, keratin layer, continuous renewal
- chemical - antimicrobial compounds, resident microflora
2
Q
What is the role of TLRs?
A
- recognise specific compunds
- activation of TLRs, production of chemokines, attracts immune cells - starts the cascade
3
Q
What does the innate immune system recognise?
A
- PAMPs: pathogen associated molecular patterns
- peptidoglycan fragments (bacteria)
- proteins (bacteria)
- nucleic acids (viruses and bacteria)
- cell wall lipids (gram negative bacteria)
- carbs (fungi, bacteria)
- DAMPs: damage associated molecular patterns
- stress-induced proteins (heat shock proteins)
- nuclear proteins
4
Q
What are some of the normal microbiota of the skin?
A
- staphylococcus
- s. epidermidis
- s. aureus
- micrococcus
- diptheroids
- malassezia furfur
all of these stop other bacteria colonising
5
Q
Name some diseases associated with skin infections?
A
- pruritis (itchy)
- alopecia
- scaling/ crusts
- pyoderma (pustules, superficial or deep)
- erosions, ulcers, pigment disorders, nodules and tumours, sinus tracts
6
Q
What types of infection can bacteria produce? (2)
A
- superficial infections
- surface pyodermas and superficial folliculitis
- deep infections
- furunculosis and nodules/ sinus tracts
7
Q
What are the aetiologies of pruritus?
A
- allergy
- atopy
- fleas
- arthropods
- food
- contacts
- infectious agents
- staphylococci
- other bacteria
- malassezia
- dermatophytes
- ectoparasites
- sarcoptes
- cheyletiella
- demodicosis
- lice
- trombicula
- others
- neoplasia
- immune mediated
- contact dermatitis
8
Q
How does alopecia occur?
A
- bacteria colonise/ infect hair follicle
- infection triggers innate and adaptive immune responses
- folliculitis
- damage to hair shafts
- atrophy
9
Q
What is this showing? and what are the different coloured dots?
A
- folliculitis/ sinus formation
- red/ yellow = bacteria
- blue = immune cells
10
Q
What is pyoderma caused by?
A
- commonyl caused by staphylococci/ streptococci
- cats, dogs - S. pseudintermedius
- horse, cattle, sheep - S. aureus
- also Group A strepococci
- pasteurella
11
Q
What are the types of pyoderma?
A
- superficial
- coagulase + staphylococci
- pasteurella. streptococci
- exudative dermatitis: staphylococcus hyicus, dermatophilus congolenis
- deep (damage)
- subcutaneous abscess
- cellulitis
- necrotising fascitis (rare) < streptococcus canis
12
Q
How does a pustule form?
A
- bacteria start growing
- influx of neutrophils
- neutrophils and dead bacteria form the pustule at the surface
13
Q
Label
A
14
Q
What condition does this dog have?
A
15
Q
What is this an example of?
A
- deep pyoderma
