Microbio Chapter 21- Microbial Diseases of the Skin and Eyes Flashcards
What are the bacteria affecting the skin?
- Staphylococcus aureus
- Streptococcus pyogenes
- Pseudomonas aeruginosa
How does Staphylococcus aureus invade the skin?
Attach to and infect hair follicle (Folliculitis)
What are infections caused by Staph. aureus?
- Sty (eyelash folliculitis)
- Furuncle (Pus, red, swollen)
- Carbuncle (Tissue under skin inflamed, pus)
How is carbuncle treated?
Pus drained via surgery and use of antibiotics (penicillin)
What is a skin infection caused by Staphylococcus aureus that commonly affects new borns?
Impetigo
Impetigo appearance:
Yellowish crust, inflammation
What are two syndromes caused by Staphylococcus aureus?
SSSS and TSS
What is SSSS?
Staphylococcus Scalded Skin Syndrome
-Skin develops redness, blisters form, fill with a clear liquid (NO PUS), peel off skin and leave person vulnerable to a secondary infection
Why does SSSS happen?
Staphylococcus aureus releases an exfoliative exotoxin
What is the mechanism of exfoliative exotoxins?
Destry skin cells by breaking up ester bonds
What is TSS?
Toxic Shock Syndrome
What increases risk of TSS?
Tampon use
Surgical wound
Child birth
Why do tampons lead to TSS?
The material is abrasive and upon insertion lead to small cuts that are prone to infection due to the nutrient rich environment
What TSS toxins are associated with tampon use and surgical wounds?
TSS toxin-1 and toxin-2
TSS symptoms:
Fever, headaches, muscle aches, nausea, confusion, kidney failure, SSSS, shock and death (Less than 3%)
How can TSS be prevented?
Handwashing
Pad use
Frequent changing of tampon (look at absorbency)
What is the name of the group that Streptococcus pyogenes is a part of?
Group A beta haemolytic strep
Why is Streptococcus pyrogenes more invasive?
It has M-proteins
What are skin infections caused by Streptococcus pyogenes?
Impetigo
Erysipelas
Necrotising fasciitis
What population does streptococcus pyogenes impetigo affect?
Preschool age kids: 3-5 years old
Where does Erysipelas infect?
Deeper into dermis
Erysipelas appearance:
Red patches with raised margins
What causes necrotising fasciitis to occur?
Streptococcus pyogenes enters a break in the skin
What are released during a necrotxing fasciitis invasion?
Exoenzymes (Collagenase and hyluronidase) and Exotoxin A
Does necrotising fasciitis spread?
yes can spread to other organs causing multiple organ failure
What is the death rate for necrotising fasciitis?
50% mortality rate
What happens when the ear is infected with Pseudomonas aeruginosa?
Otitis externa or swimmer’s ear
-contaminated water in ear
What happens when the skin is infected with Pseudomonas aeruginosa?
Dermatitis
-A rash caused by dirty pools/hot tubs
Pseudomonas aeruginosa infection: Post-burn victims
Increased blue/green pus (pyocyanin), longer hospital stay and increased death rate (2/3rd)
Pseudomonas aeruginosa infection: Cystic fibrosis patients
Bacteria evades phagocytosis and lungs are infected
Where is Pseudomonas aeruginosa growth seen?
Flower vases, mop water, antibiotics and antiseptics
-Carbon loving
What are opportunistic infections caused by pseudomonas aeruginosa?
Burn victims, CF patients
What bacteria causes acne?
Propionibacterium acnes
What are viral diseases that affect the skin?
Human Papilloma virus
Herpes Simplex virus
Measles
Rubella