Microbial disease of the skin and eyes Flashcards
1
Q
Skin
A
- Epidermis
- Dermis
- Mucous membrane
2
Q
Epidermis
A
- Thin outer layer
- waterproof
- Stratum corneum
- keratin
3
Q
Dermis
A
- thick inner layer of the skin
- many connective tissues
- hair follicles, sweat glands , and oil glands
- mircoorganisms can enter the body via these - Perspiration
- Sebum
4
Q
Perspiration
A
- Provide moisture and some nurtients for microbial growth
- contains salt
5
Q
Sebum
A
- secreted by oil glands
- mix of lipids, proteins and salts
- prevents hair and skin from drying out
6
Q
Mucous membrane
A
- lines the body opengsing and open to the exterior
- gastrointestinal, respiratory, urinary and genital tract
- outer protective barrier
- tighly packed epitheial tissue
- often acidic
- folded
7
Q
Normal microbiota
A
- resistant to drying and high salt concentration
- gram pos. cocci
- staphylocci and micrococci
yeast causes dandruff
- staphylocci and micrococci
8
Q
Microbial disease of the skin
A
- exanthem
- skin rash from disease
- a breakout
- Enanthem
- rash on the mucous membrane from disease
9
Q
Types of skin lesions
A
- Vesicles
- small, fluid filled lesion
- Bullae
- vesicle larger than 1cam in diameter
- Macules
- flat, reddened lesion - paplules
- raised lesions
10
Q
Staphylococcal skin infections
A
- gram pos.
- coagulase
- enzymes that clot fibrin in the blood
- used to identify staphylococci
S. epidermidis
- used to identify staphylococci
- 90% of normal skin mircobiota
- healthcare associated infection
- biofilm
- coagulase- neg
S. aurease
- 20% of nasal pathway- coagulase pos.
- avoids host defenses in the skin
- enzymes that clot fibrin in the blood
11
Q
Staphylococcal skin infections PT.2
A
- Folliculitis:
- infection of hair follicles
- Sty
- infection of the eyelash
- Furuncle (boil)
- type of abscess, localized region of pus in inflamed tissue - Carbuncle
- damage and inflammatior of deep tissue from spreading furuncle - Impetigo
- crusting sores spread by autoinoculation
12
Q
Streptococcal skin infections
A
- gram pos. cocci in chains
- produce hemolysins that lyse red blood cells
- beta-hemolytic streptococci often casue disease
- group A- T based on their antigenic cell wall
Group A strep. (GAS)- Streptococcus pyogenes
- produces virulence factors
- streptolysins: lyse RBCs
- M proteins: allow adherence and immune system avoidance
- produces virulence factors
- Streptococcus pyogenes
- Erysipelas
- infection of the dermis layer
- cause by local tissue destruction and sepsis
- S. pyogenes
Necrotizing fasciitis- flesh eating disease
- exotoxin A acts as a superantigen
13
Q
Acne
A
- caused by blockage of hair follicles and sebum
- comedonal (mild) ance
- topical formation
- inflammatory (moderate) acne
- caused by propionbacterium acnes
- metabolizes sebum and fatty acids produce inflammatory response- treated w/ antibiotics and benzoyl peroxide
- Codular cystic (severe) acne
- inflamed lesion w/ pus deep in the skin
14
Q
Viral skin disease
A
- Warts
- Papillomas: small skin growths
- from contact
- HPV
- treated w/ cryothearpy, electrodesiccation or salicylic acid
- Smallpox
- Orthropoxvirus
- 2 forms Variola major 20% mortality
- Variola minor less than 1% - spread via respiratory and moves into the bloodstream and infects skin
- eradicate by vaccines
- Chickenpox
- Varicella
- human herpesvirus 3
- via respiratory route - pus filled vesicles
- Reye’s disease
- severe complication of chickenspox
- vomiting and brain dysfunction
- preventable by vaccine
15
Q
Shingles
A
- herpes zoter
-reactivation of latent aricella -zoter viruse moves along peripheral nerves - affects cutaneous sensory nerves
- limited to 1 side of the body
- preventable by vaccine
