Skin I

Question 1

describe the natural defenses of the skin

Answer 1

• keratin
• antimicrobial peptides (AMPs): host defense
• skin sloughing
• sebum:
  
  • low pH
  • lipid (sphingoid bases)
• sweat:
  
  • low pH
  • high salt
  • lysozyme (digests peptidoglycan)

Question 2

sebum has a ___ pH and contains ___

Answer 2

sebum has a low pH and contains lipid (sphingoid bases)

Question 3

sweat has a ___ pH, high ___ and contains ____ which helps digest ____

Answer 3

sweat has a low pH, high salt and contains lysozyme which helps digest peptidoglycans

Question 4

____ spp. predominate in sebaceous areas

Answer 4

Propionibacterium spp. predominate in sebaceous areas

Question 5

____ spp. predominate in moist areas

Answer 5

Corynebacterium and Staphylococcus spp. predominate in moist areas

Question 6

dry areas of the body exhibit ____

Answer 6

dry areas of the body exhibit the greatest amount of diversity and lower load (less selective force)

Question 7

susceptibility genes such as ____ can lead to higher rates of ____

Answer 7

susceptibility genes such as filaggrin can lead to higher rates of atopic dermatitis

Question 8

contrast primary vs. secondary skin infections

Answer 8

• primary: skin infections caused by a single pathogen and affect normal skin
  
  • ex: SA, B-hemolytic strep.
• secondary: occur in skin that is already diseased
  
  • overgrown resident flora
  • toe web infection (athlete’s foot) regarded as a fungal infection is now believed to be caused first by dermatophytes, which cause skin damage that allows bacterial overgrowth of certain coryneform bacteria and Brevibacterium

Question 9

Pseudomonas aeruginosa is the leading cause of ____ and is known for causing infections in patients with ____ (3 things)

Answer 9

Pseudomonas aeruginosa is the leading cause of nosocomial G-ve associated infections and is known for causing infections in patients with extensive burns, patients treated with cytotoxic drugs and patients with CF

Question 10

a major virulent factors of Pseudomonas is its capacity to ____ and one of its most worrying characteristics is its ____

Answer 10

a major virulent factors of Pseudomonas is its capacity to form biofilms and one of its most worrying characteristics is its low antibiotic susceptibility

Question 11

Pseudomonas has an ____ mode of metabolism, which means that ___ is NOT employed

Answer 11

Pseudomonas has an obligate resp. mode of metabolism, which means that fermentation is NOT employed

• does NOT ferment lactose, which sets them apart from the Enterobacteriaceae

Question 12

____ test is a rapid test which is used for the presumptive identification of group A B-hemolytic streptococci and enterococci

Answer 12

PYR (pyrrolidonyl arylamidase) test is a rapid test which is used for the presumptive identification of group A B-hemolytic streptococci and enterococci

Question 13

PYR (pyrrolidonyl arylamidase) test is a rapid test which is used for the presumptive identification of _____

Answer 13

PYR (pyrrolidonyl arylamidase) test is a rapid test which is used for the presumptive identification of group A B-hemolytic streptococci and enterococci

Question 14

describe the function of protein A

Answer 14

Question 15

the target of exfoliative toxin found in S. aureus is ____

Answer 15

the target of exfoliative toxin found in S. aureus is desmoglein-1

Question 16

it is important to differentiate Strep. from Staph. because Staph. is ____

which 2 lab tests can differentiate?

Answer 16

it is important to differentiate Strep. from Staph. because Staph. is resistant to penicillin G

Gram staining and catalase test can differentiate