Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Endocrine Revision > An Introduction to the Microbiology of the Skin > Flashcards

An Introduction to the Microbiology of the Skin Flashcards

1
Q

• What skin microenvironments are created?

A

Elevated temperature with humidity, occluded sites (digital webs) & other factors (exposure to UV light, diet & hormonal changes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

• What skin factors effect microbiology?

A

Skin mostly dry – affects ability to adhere, pH, salinity, nature of lipids and immune response, antimicrobial peptides in sweat, transferrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

• What factors predispose niches to colonisation?

A

Local secretions, local pH, contamination from local structures, moisture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

• What are resident and transient organisms?

A

Resident – can replicate on the skin and can persist

Transient – cannot replicate so stay for a short time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

• What is the most common yeast commensal?

A

Malassezia pachydermatitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

• What approach would you take to concurrent Malassezia and Staphylococcus pseudintermedius samples being found on a swab?

A

Treat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

• What type of bacteria would you not expect to find on a routine swab?

A

Gram –ve & rods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

• What are the common features of the Staphylococcus species?

A

Gram +ve, catalase positive, facultative anaerobes, oxidase negative, non-motile, four types of haemolysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

• How do you distinguish between S. aureus & S. pseudintermedius?

A

S. aureus can ferment maltose, S. pseudintermedius cannot

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

• What virulence factors to Staphylococcus species possess?

A

Coagulase, lipases, elastase, protein A inhibits opsonisation & a range of toxins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

• With regards to treatment, what do most staphylococcus species produce?

A

β-lactamase enzyme which inactivates penicillin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

• What do MRSP and MRSA stand for?

A

MRSP – methicillin resistant staphylococcus pseudintermedius

MRSA – methicillin resistant staphylococcus aureus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

• What are pseudomonas?

A

Rod shaped, gram –ve, aerobic, non-spore forming bacteria, associated with a wide range of opportunistic infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

• What are the naturally occurring defences by the skin?

A

Secretory immunoglobulin A, cell-mediated immunity, physical barrier, desquamination (constant flow of cells), poor conditions – dry & low pH, competition by normal flora

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

• What barriers help provide innate immunity?

A

Physical barrier, antimicrobial peptides, mucus, complement, phagocytic cells, lymphocytes and NK cells, mast cells, cytokines and chemokines, the development of inflammation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

• What are the mechanisms by which microbes can avoid host detection?

A

Antigen variation, inhibition of antigen processing, inhibition of complement activation, resistance to phagocytosis, inactivation of reactive oxygen species, escape from phagolysosome, production of cytokine receptor homologues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

• What is the result of superantigens?

A

Superantigens over active T lymphocyte by passing the normal process, activation by binding MHC and lymphocytes but not through the peptide binding cleft, this can lead to cytokine production and an inflammatory response

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

• What factors impact on the cutaneous environment?

A

Moisture/humidity, damage, normal tissue maintenance, washing, behaviour, health & physical breaches of the barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

• What are the usual primary causes that result in proliferation of commensals?

A

Hypersensitivity, systemic disease, damage compromise of defences

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

• What may skin disease be due to?

A

A virulent pathogen, proliferation of normal commensals, penetration through damage of skin by commensals or pathogens, disruption of the normal skin biology allowing secondary infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

• What are the three general terms for infection?

A

Surface infection – colonisation of lesions on the skin surface
Superficial infection – involves sin and hair follicle epithelium
Deep infection – involves the dermis and subcutaneous tissue

22
Q

• What is a secondary infection?

A

When defences compromised by an existing condition allow further organisms that would not normally cause disease to cause infection

23
Q

• What are the most common cutaneous infections?

A

Canine – staphylococcus pseudintermedius
Feline – subcutaneous abscesses
Cattle – dermatophytosis (ringworm)
Pig – greasy pig disease (staphylococcus hyicus)
Sheep – sheep scab
Horse – Dermatophilus (mud fever)

24
Q

• What is one of the possible causes of mastitis in cattle?

A

Staphylococcus aureus

25
Q

• What is an abscess?

A

A collection of pus formed by tissue destruction in an inflamed area of a localised infection, prevents the spread of infectious material and attracts white blood cells to the site

26
Q

• What is the coagulase test?

A

Sample is added to rabbit plasma, positive samples will cause the serum to coagulate

27
Q

• What are some of the common organisms associated with mastitis?

A

Streptococcus & E. coli

28
Q

• What is the agent that causes cutaneous streptothrichosis (mud fever)?

A

Dermatophilus congolensis – gram +ve, filamentous bacterium

29
Q

• In which species is Dermatophilus most frequent?

A

Cattle, sheep, goats and horses

30
Q

• What are the two characteristic forms of Dermatophilus?

A

Filamentous hyphae and motile zoospores

31
Q

• Describe the pathogenesis or Dermatophilus

A

Zoospores attracted to sites on skin, germinate to produce hyphae which penetrate into the living epidermis causing an acute inflammatory reaction

32
Q

• What is the difference between an acute and a chronic infection of Dermatophilus?

A

Acute infections normally cease within 2-3 weeks and lesions heal spontaneously
Chronic infections affect hair follicles and scabs from which intermittent invasions on non-infected hair follicles and epidermis occurs

33
Q

• What factors are critical to the establishment of a fungal infection?

A

Exposure, critical mass of infective material, grooming effectively removes material, spores require warm humid conditions to infect, pre-existing skin conditions, immune status

34
Q

• What are the three types of Mycotic infections?

A

Superficial – skin, hair and claws
Intermediate – infections of the dermis and subcutaneous tissues
Deep – subcutaneous and systemic infections

35
Q

• What is dermatophytosis?

A

Ringworm

36
Q

• How can you distinguish between different dermatophytes?

A

Features of the conidia – the asexual, non-motile spores, normally stained with lactophenol cotton blue

37
Q

• What is the most common cause of ringworm in cattle and horses?

A

Cattle – Trichopyton verrucosum, horses – T. equinum

38
Q

• What is Microsporum gypseum?

A

A soil saprophyte – causes ringworm

39
Q

• What are the two groups of asymptomatic canine and feline carriers?

A

Culture positive dogs r oats with subtle active infections OR no active infection

40
Q

• What is the pathology of ringworm?

A

Incubation period is approximately 1 week, fungus invades anagen hairs by digestion of keratin, inflammatory response leads to folliculitis or furunculosis

41
Q

• What is the most common dermatophyte of dogs and cats?

A

Microsporum canis

42
Q

• What is the most typical yeast commensal found on healthy canine skin and mucosa?

A

Malassezia pachydermatitis

43
Q

• What are deep mycoses?

A

Infections invading deep in to the skin, may produce skin lesions secondary to systemic infections – most common deep mycoses of cats is Cryptococcus neoformans

44
Q

• What are some of the common diagnostic techniques used in dermatology?

A

Examination of coats with lens, flea combing, acetate tape prep, cytology, trichogram, skin scrapings, Wood’s lamp examination, fungal culture dermatophytes, bacterial culture, skin biopsies

45
Q

• What is the common medium used for fungal culture dermatophytes?

A

Dermatophyte test medium (DTM)

46
Q

• What is Wood’s lamp examining for?

A

Dermatophytes – 50% of M. canis strains produce metabolites following hair invasion which fluoresce (some bacteria and other chemicals will also fluoresce)

47
Q

• What is a trichogram?

A

A microscopic examination of plucked hair (hair immersed in mineral oil)

48
Q

• What is the common cattle virus that causes warts?

A

Bovine papilloma virus – five strains, BPV-type I to type V

49
Q

• What are some common dermatological viruses of dogs and cats?

A

Dogs – distemper virus, papilloma virus

Cats – pox virus, feline parapoxvirus, contagious pustular dermatitis

50
Q

• What does DTM contain?

A

Phenol red (pH indicator), cyclohexaimide (inhibits growth of other fungi) & gentamicin and cholorotetracycline (inhibits bacterial growth)

51
Q

• How does coagulase react in blood?

A

Coagulase is an enzyme produced by S. aureus that reacts with prothrombin in blood to produce staphylothrombin, which causes blood to clot by converting fibrinogen to fibrin

Endocrine Revision (45 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions