M5: Staphylococcus

Question 1

Staph shape

Answer 1

• round

- tends to form grape-like clusters with other bacteria

Question 2

Staph gram stain

Answer 2

Gram-positive

Question 3

Staph catalase test

Answer 3

positive

Question 4

Staph coagulase test

Answer 4

positive

Question 5

Staph overview

Answer 5

• facultative anaerobe
• commensal bacterium
• found asymptomatically in ~30% of population
• under correct circumstances (such as compromised immunity), colonies spread rapidly causing severe illness

Question 6

way of differentially screening for staph

Answer 6

• culture it in presence of bile salts

- will be able to grow when other bacteria won’t

Question 7

common diseases caused by Staph (5)

Answer 7

• Folliculitis
• Scalded Skin Syndrome
• Impetigo
• Conjunctivitis
• Opthalmia Neonatorum

Question 8

Folliculitis

Answer 8

• caused by staph aureus
• affects hair follicules, forming lesions (pustules)
• larger lesions (boils & carbuncles) can form anywhere on skin surface

Question 9

Scalded Skin Syndrome

Answer 9

• caused by staph aureus
• usually seen in infants/young kids
• causes pustules that rupture to reveal peeling skin that looks scalded
• treated via Penicillin or Erythromycin

Question 10

Impetigo

Answer 10

• caused by staph aureus
• contagious childhood skin disease
• presents as fluid filled red sores near mouth/nose
• sores are often itchy/uncomfortable
• if sores are scratched/rubbed/rupture, they can spread across body or to others
• treated via Penicillin

Question 11

Conjunctivitis

Answer 11

• infection of conjunctiva (transparent tissue covering sclera and inner eyelid surface)
• can be caused by bacteria (most commonly Staph) or virus
• viral conjunctivitis is accompanied by symptoms of common cold
• best prevention = handwashing
• common in children, can spread rapidly

Question 12

Symptoms of conjunctivitis

Answer 12

• red/pink color in one or both eyes
• painful burning / itching
• eyes stuck shut due to tear production

Question 13

Opthalmia Neonatorum

Answer 13

• severe bacterial conjunctivitis in newborns
• caused by exposure to chlamydia or gonorrhea as baby passes thru birth canal
• can cause permanent eye damage w/out immediate treatment
• babies get neomycin ointment in eyes to prevent