Lecture 21

Question 1

Bacterial Infections of Skin and soft tissue

Answer 1

• infection happens after deep tissue entry

- Staphylococcus and Streptococcus are the most common skin pathogens (gram positive survive in dry salty conditions)

Question 2

Skin disease

eg. Staphylococcus aureus

Answer 2

• gram positive
• part of normal flora in some people
• move down hair follicles into sebaceous glands
• inflammation and accumulation of phagocytic cells

Question 3

S. aureus skin infections – Typical clinical presentations 3

Answer 3

Folliculitis = small red bumps

Furuncles (“boils”)

Carbuncles = several furuncles (boils)

Question 4

S. aureus skin infections

Reservoir

Transmission

Prevention

Treatment

Answer 4

skin and nasal passages of humans (carried asymptomatically)

Direct contact, fomites, resp. droplets

Hand hygiene (chlorhexidine wash to decolonize pts)

Surgical drainage of pus and antibiotics (methicillin)

Question 5

Other skin conditions caused by S. aureus:

Scalded skin syndrome

Answer 5

produce exfoliation toxin (destroys material holding epidermis to dermis

• kids
• redness and soft blisters
• skin peels leaving wet, scalded looking areas

Fatal (protective isolation, antibiotics, removal of dead skin)

Question 6

3. Bacterial Infections of the Genitourinary Tract

Answer 6

GU tract pathogen sensitive to environmental stress, survive short time outside of host

direct contact (sex, mother to fetus, body fluid)

Question 7

Neisseria gonorrhoeae(flow of seed)

Answer 7

• gram negative cocci in pairs
• fragile
• humans only reservoir and host

Question 8

Neisseria gonorrhoeae Pathogenesis 3

Answer 8

1. Attach to genital tract
2. Invades epithelial cells and enter into sub-epithelial tissues
3. Tissue dmg allow release of bacteria

Question 9

Neisseria gonorrhoeae symptoms

Answer 9

Female: inflammation, burning urine
asymptomatic

Male: Urethral canal inflammation, painful urination, discharge of pus

1% go into blood
-joint inflamm. skin rash/pus, heart/liver infection

Question 10

Complications from N. gonorrhoeae infections

Answer 10

• urethral scarring and possible infertility (male)
• Pelvic inflammatory disease (female) (scarring of tubes)
• Transmission to infant (eye infection blindness)

Question 11

Neisseria gonorrhoeae diagnosis and control

Answer 11

Nucleic acid amplification (PCR) on urine
-screen carrier and confirm disease

Resistant to penicillin, erythromycin, tetracycline
-Ceftriaxone (single IM injection)+ Azithromycin (single oral dose)
,
No immunity, switches pili to avoid immune response

no vaccine