Chapter 21: Microbial Diseases of Skin Flashcards
Vesicles:
Small fluid-filled lesions.
(If larger than 1cm, is called a bulla.
Bullae:
Larger fluid-filled lesions (>1cm)
Macules:
Flat lesions (often reddish)
Papules:
Raised lesions.
When they contain pus are called Pustules
Pathogenic Bacteria of Skin
»Folliculitis:
S. aureus entering body through natural opening (hair follicle)
Ex. Sty, an infected follicle of an eyelash.
Furuncle & Carbuncle are present
Carbuncle:
Hard round deep inflammation of tissue under the skin.
(Deeper into tissue causes symptoms of Fever)
Furuncle:
(Boil) abscess, localized region of pus surrounded by inflamed tissue
Pathogenic Bacteria of Skin
»Impetigo:
S. aureus
> Nonbullous impetigo:
- Most common form
- Pathogen enters through minor break in skin
- Sympt: host’s response to infection.
Generally heals without treatment/scarring.
Pathogenic Bacteria of Skin
» Scalded Skin Syndrome
S. aureus
> Bollous impetigo:
- Most pathogenic
- Caused by Staph toxin
- Exfoliative toxin A- localized
- Exfoliative toxin B- distant sites
- Cause separation of skin layers
Pathogenic Bacteria of Skin
» Toxic Shock Syndrome TSS
S. aureus
- Life threatening condition
- Fever, vomiting, sunburn-like, organ failure
- Originally known as Staphylococcal growth w/use of tampons
Which Gram+ bacterium causes inflammatory acne?
Propionibacterium acnes
What are comedos and comedones?
- Comedos: whiteheads
- Comedones: blackheads
What is a virulence factor?
Characteristics of the ability of a microbe to cause disease.
Ex. Structure, enzymes, proteins
What are the names of the toxins that cause scalded skin syndrome?
- Exfoliative toxin A- localized
- Exfoliative toxin B- distant
Allow bacteria to penetrate
Cause separation of skin layers
Which two bacteria cause impetigo?
- Staphylococcus aureus
- Staphylococcus pyogenes (group A beta strep)
How does TSST-1 affect the body?
- Toxic Shock Syndrome Toxin 1:
Tampons being left in body too long, forms at growth site releases toxins and circulates in bloodstream.
Which organic acid produced by fermenting bacteria causes inflammation in the skin?
-Propionic acid.
Metabolizes sebum and forms free fatty acids.
Which type of acne is the most severe?
Nodular cystic acne
What is the basis for subdividing Streptococcus into smaller divisions? (be able to recognize Greek letters)
Alpha - some hemolysin activity (partially lyse)
Beta - Strong hemolysin activity (fully lyse)
Gama - No hemolysin activity (no lyse rbc)
Why are the Group A β Strep relevant? (GAS)
- Most common human pathogens.
- Produce streptolysins: lyse RBC and are toxic to neutrophils
- Promote rapid spread of infection by liquefying pus.
In what groups of people does Group B β Strep mainly cause disease?
- Newborn babies (can be passed during childbirth b/c mom has it apart of their microbiome)
- Pregnant women
- Elderly
- Immunosuppressed people
What are the toxins that contribute to necrotizing fasciitis?
Pyrogenic toxins
Which bacterium is associated with water and can cause problems with swimmers or bathers?
- Pseudomonas aeruginosa
causes Pseudomonas dermatitis because pores open up in warm water; allow bacteria to enter.
How does measles spread?
- Rubeola (paramyxoviridae)
Spread by the respiratory route droplets
